Diagnosis and appropriate treatment in clinical endocrinology rely heavily on the accurate use and interpretation of diagnostic tests. This handbook was devised as a means of guiding new junior staff (and refreshing the memories of their seniors!) when confronted by clinical problems and their investigation. This bible is meant to be brief and didactic with the inevitable costs as well as benefits of such an approach. It is envisaged that it will be reprinted at 6 monthly intervals incorporating corrections and additions, any suggestions and comments from readers are welcome.

Grateful acknowledgements are due to: Professor Stephen Bloom, Dr Simon Wallis, Professor Graham Joplin, Professor Kaye Ibbertson, Professor James Jackson, Dr Jacky Burrin, Mrs Sophie Barnes, Mrs Veronica Ferguson, Mr Stuart Lavery, Mr Paul Bains and all our colleagues for their help and encouragement.

We are delighted to note that this bible is forming the basis of many Endocrine protocols on various website around the country. The first version of this was written by the Registrars and Consultants in the Endocrine Unit in 1988 and used as a handbook for the junior doctors ever since. It has been available on the web since 1999 and it has since been widely used as the central source of endocrine protocols ever since. Please feel free to use this information to educate your own staff, and please simply acknowledge the Imperial College Endocrine Unit.

Authors

Andrew Hattersley	Maria Barnard	John Wilding	Stephen Gilbey	Peter Hammond
Michela Rossi	Duncan Bassett	Arshia Panahloo	Rachel Batterham	Maha Barakat
John Frank	Bernard Khoo	Jeannie Todd	Sarah Stanley	Elaine Murphy
Carel LeRoux Tricia Tan	Waljit Dhillo Jaideep Dhariwal	Karim Meeran Debbie Peters	Niamh Martin Jaimini Cegla	Emma Hatfield Fausto Palazzo

May 2010

Endocrine Unit

ANTERIOR PITUITARY

ANTERIOR PITUITARY FUNCTION

INSULIN TOLERANCE TEST (ITT)

INDICATION

Assessment of ACTH and cortisol reserve.

Assessment of growth hormone reserve in children with definite growth retardation and a subnormal growth hormone stimulation test (see exercise test).

Differentiation of Cushing's syndrome from depression.

GH response in adults.

CONTRAINDICATIONS

Ischaemic heart disease, Epilepsy,

Untreated hypothyroidism (impairs the GH and cortisol response).

Serum cortisol <100nmol/L

PREPARATION

The patient should fast overnight (water permitted) and be recumbent during the test. Medications can be given after completion of the test ie by lunchtime. If patient is taking hydrocortisone, then the last dose should be at midday the day before the test (ie omit evening dose and dose on morning of test).

ECG must be normal and the patient's weight known.

In peri-pubertal children (bone age > 10 years) priming is needed

M: 100 mg testosterone enantate i.m. (single injection) 3 days before test

F: 100 mcg ethinyloestradiol p.o. each for three days before the test.

Calculate Actrapid Insulin dose:

Normal pituitary function 0.15 U/kg

Hypopituitary 0.10 U/kg

Acromegaly, diabetes, Cushing's 0.2-0.3 U/kg

If the patient is hypoadrenal for any reason (or on hydrocortisone), the case must be discussed with senior medical staff before administration of insulin. Patients with a cortisol <100 are very unlikely to have a normal response and may therefore not need the test.

50mls 50% dextrose available for immediate administration (but only use if persistent hypoglycaemia).

Glucometer.

6 fluoride oxalate tubes (grey top Vacutainers)

6 serum (clotted) tubes (red top Vacutainers)

SIDE EFFECTS

Sweating, palpitations, loss of consciousness and rarely convulsions.

METHOD

1. Site indwelling cannula.

2. At 0 minutes, take baseline bloods and then inject insulin i.v.

3. Take samples for GH, cortisol and glucose at 0, 30, 60, 90, and 120 mins, flushing the cannula with saline between samples.

4. At 30 minutes check whole blood glucose with Glucometer and repeat the insulin dose if not hypoglycaemic (this will mean prolonging sampling by 30 min).

5. Adequate hypoglycaemia (£2.2mmol/l) should be symptomatic. Record symptoms in the notes. Once this has been achieved, patients need not remain hypoglycaemic.

6. There must be at least 2 specimens following adequate hypoglycaemia. This does not mean that the patients need spend that long hypoglycaemic.

7. At all times a doctor or nurse must be in attendance. A doctor should be present to administer the insulin but can leave once glucose levels start to rise following hypoglycaemia. The lowest glucose level following IV insulin is usually at 20-30 minutes, with spontaneous resolution.

8. Reverse hypoglycaemia with simple oral treatment (juice/lucozade). If symptoms very severe or patient unrousable (rare) consider giving i.v. 20%-50% dextrose (10-15 ml, can dilute 50% with saline), or 1 mg i.m. glucagon (1 amp), and continue sampling.

9. Obtain specimen for glucose before reversal of symptoms.

10. Check whole blood glucose on glucometer every time a specimen is taken.

11. If a patient has a hypoadrenal crisis they should receive i.v. 0.9% saline and hydrocortisone 100 mg.

12. Once test completed, give supervised meal.

13. Patient should not drive for 2 hours after the test.

INTERPRETATION

· The test cannot be interpreted unless hypoglycaemia (£2.2mmol/l) is achieved.

· Adequate cortisol response is defined as a rise of greater than 170 nmol/l to above 500 nmol/l. Patients with slightly impaired cortisol responses may only need steroid cover for major illnesses or stresses. They will need instruction about this and should carry a steroid card.

· In Cushing's syndrome there will be a rise of less than 170 nmol/l above the fluctuations of basal levels of cortisol.

· Adequate GH response is a rise to >6mcg/L (>20 mU/L). In adults this may be a sensitive indicator of hypopituitarism but its principal role is in children who may require GH treatment. In children a rise to greater than 12 mcg/L (39 mU/L) is considered normal. Appropriate priming is very important if they are peri-pubertal. Before treatment with growth hormone children should have two stimulatory tests.

SENSITIVITY AND SPECIFICITY

If there is adequate hypoglycaemia and the patient is not hypothyroid then cortisol response is a good test of ACTH/adrenal reserve. 5-15% of normals will show a suboptimal response as defined by these two criteria.

20% of patients with Cushing's syndrome will show a rise greater than 170nmol/l but a rise of less than this is rare in depression or alcoholic pseudo-Cushing's.

GH responses are reduced in 20% of normal children and some small children whose peak GH is 3-6mcg/L (10-20mU/l) may benefit from GH replacement.

REFERENCES

Plumpton et al., Br. J. Surg. 56, 21 (1969). Greenwood et al., J. Clin. Invest. 45, 429 (1965).

GLUCAGON TEST

INDICATION

Assessment of growth hormone and ACTH/cortisol reserve especially when insulin-induced hypoglycaemia is contra indicated. This is a good assessment of GH reserve. Cortisol results should be interpreted with caution in light of the clinical picture.

Medications can be given after completion of the test ie by lunchtime. If patient is taking hydrocortisone, then the last dose should be at midday the day before the test (ie omit evening dose and dose on morning of test).

CONTRAINDICATIONS

Phaeochromocytoma or insulinoma (may provoke an attack)

Starvation >48 hours or glycogen storage diseases (inability to mobilise glycogen may result in hypoglycaemia)

Severe hypocortisolaemia (0900h level <55 nmol/l)

Thyroxine deficiency may reduce GH and cortisol response.

SIDE EFFECTS

Nausea is common (30%) and patients may rarely vomit.

PREPARATION

Fasting from midnight. The patient does not need to be continually observed as hypoglycaemia is not provoked.

Calculate glucagon dose: adults: 1 mg, (1.5mg if > 90kg) children: 15 mcg/kg

6 fluoride bottles (grey top Vacutainers) and 6 plain tubes (red top Vacutainers)

METHOD

1. Insert an indwelling cannula.

2. Take basal samples for glucose, cortisol and GH.

3. Give the glucagon i.m. (the deltoid may be a suitable site).

4. Take further samples at 90, 120, 150 and 180 minutes.

INTERPRETATION

Adequate cortisol response is defined as a rise of greater than 170 nmol/l to above 500nmol/l. Adequate GH response is a rise to a value greater than 6mcg/L.

SENSITIVITY AND SPECIFICITY

This test is probably slightly less reliable test of somatotroph and corticotroph function than the ITT. It is an excellent alternative in patients who can not tolerate hypoglycaemia because of epilepsy, ischaemic heart disease or hypopituitarism (cortisol <100nmol/L).

REFERENCES

Rao R.H. et al., Metabolism 36, 658-663 (1987).

ATH 12/89.

THYROTROPHIN RELEASING HORMONE (TRH) TEST

INDICATION

To assess TSH reserve. Differential diagnosis of pituitary and hypothalamic causes of TSH deficiency.

CONTRAINDICATIONS

As patients should be off thyroxine for 3 weeks prior to test so this test, it is rarely used in people on thyroxine.

PREPARATION

Overnight fast not necessary.

200 mcg TRH

i.v. cannulae 19 or 21 gauge.

3 x clotted tubes (red top Vacutainers): 6 ml per sample.

SIDE EFFECTS

Patients should be warned that they may have transient side effects after the injection such as a metallic taste in the mouth, flushing and mild nausea, and should be on a recliner or bed.

METHOD

1. Site indwelling cannula.

2. Take baseline bloods for TSH and thyroxine.

3. Inject TRH slowly i.v. over 2 minutes.

4. Flush butterfly with heparin/saline.

5. Take samples for TSH at t = 30 mins and 60 mins.

INTERPRETATION

The normal result is a TSH rise to >5 mU/l with the 30 min value exceeding the 60 min value.

If the 60 min sample exceeds the 30 min value then this usually indicates primary hypothalamic disease.

In hyperthyroidism, the TSH remains suppressed and in hypothyroidism there is an exaggerated response. With the current sensitive TSH assays basal levels are now adequate and dynamic testing is not usually needed to diagnose hyperthyroidism.

SENSITIVITY AND SPECIFICITY

An inadequate rise of TSH is not an indication for thyroxine replacement unless the serum thyroxine, free T4 or free T3 is reduced. The TSH is not only undetectable in pituitary disease and thyrotoxicosis but also in some cases of euthyroid ophthalmic Grave’s disease and multinodular goitre.

A late rise in TSH may be seen rarely in thyroid and pituitary disease as well as hypothalamic disease.

REFERENCE

Hall et al., Lancet i: 759-63 (1972).

ATH 11/89

GONADOTROPHIN RELEASING HORMONE GnRH/LHRH TEST

INDICATION

1) To further investigate possible gonadotrophin deficiency.

2) To confirm precocious puberty.

PREPARATION

Overnight fast not necessary if done alone.

In women with a normal menstrual cycle the test should be performed in the follicular phase (day 3-7 of the cycle).

Larger dose or priming with LHRH if suspected of hypogonadism may be necessary.

(N.B. Do not prime with sex steroids if indication 2 above)

100 mcg LHRH (GnRH – Gonadorelin).

3 clotted tubes (red top Vacutainers – 7 ml)

METHOD

1. Site indwelling cannula.

2. Take baseline bloods: LH, FSH and testosterone (M) or oestradiol (F).

3. Inject GnRH intravenously.

4. Flush cannula with saline.

5. Take samples for LH and FSH at t = 30 and 60 mins.

INTERPRETATION

· The normal peaks can occur at either 30 or 60 minutes. LH should exceed 10 U/l and FSH should exceed 2 U/l. An inadequate response may be an early indication of hypopituitarism.

· Gonadotrophin deficiency is diagnosed on the basal levels rather than the dynamic response. In males this is based on low testosterone in the absence of raised basal gonadotrophins and in females low oestradiol without elevated basal gonadotrophins and no response to clomiphene.

· Pre-pubertal children should have no response of LH or FSH to LHRH. If sex steroids are present (i.e. the patient is undergoing precocious puberty), the pituitary will be “primed” and will therefore respond to LHRH. Priming with steroids MUST NOT occur before this test.

SENSITIVITY AND SPECIFICITY

This test has a low sensitivity and specificity for hypogonadotrophic hypogonadism. The response may be normal or even exaggerated (especially in patients with hypothalamic disease). Basal levels are better discriminants. Serial investigations in patients with pituitary disease especially irradiation may give early indication of the development of hypopituitarism.

REFERENCE

Mortimer et al., BMJ, 3: 267-271.

ATH 11/89, AP 1/98.

COMBINED PITUITARY FUNCTION TESTS (CPT)

INDICATION

Assessment of all components of anterior pituitary function used particularly in pituitary tumours or following tumour treatment.

CONTRAINDICATIONS

Ischaemic heart disease.

Epilepsy.

Untreated hypothyroidism (impairs the GH and cortisol response).

SIDE EFFECTS

Sweating, palpitations, loss of consciousness and rarely convulsions with hypoglycaemia.

Patients should be warned that with the TRH injection they may experience transient symptoms of: a metallic taste in the mouth, flushing and nausea.

PREPARATION

The patient should fast overnight and be recumbent during test.

ECG must be normal and the patient's weight known.

In peri-pubertal children (bone age >10 years) priming is needed

M: 100 mg testosterone enantate i.m. (single injection) 3 days before test

F: 100 mcg ethinyloestradiol p.o. each for three days before the test.

Calculate Actrapid Insulin dose:

Normal pituitary function 0.15 U/kg

Hypopituitary 0.10 U/kg

Acromegaly, diabetes, Cushing's 0.2-0.3 U/kg

TRH (Roche) 200 micrograms as slow i.v. injection.

LH/FSH releasing hormone (GnRH) – 100 mcg as i.v. bolus.

50mls 50% dextrose available for immediate administration.

Cannula, 18-20g.

Glucometer.

6 fluoride tubes (grey top Vacutainers).

7 clotted tubes (red top Vacutainers) for samples.

500 ml bag 0.9% saline to flush cannula.

3 way tap to assist the taking of samples.

STANDARD METHOD

1. Site indwelling cannula.

2. Take baseline blood samples for testosterone/oestradiol, prolactin, thyroxine, LH, FSH, TSH, GH, cortisol (14 ml clotted) and glucose (2 ml fluoride).

3. Then at T = 0 inject insulin and GnRH i.v. as boluses followed by the TRH over 2 minutes.

4. Take samples for LH, FSH, TSH, prolactin, GH, cortisol (7 ml clotted) and glucose (2 ml fluoride) at 30, 60 minutes and GH, cortisol, glucose at 90 and 120 minutes.

5. Flush the cannula with saline between samples.

6. At 30 minutes check blood glucose with Glucometer and repeat the insulin dose if not hypoglycaemic. Adequate hypoglycaemia (≤2.2mmol/l) should be symptomatic. Record symptoms in the notes.

7. Hypoglycaemia should be reversed by giving i.v. 50% dextrose, or i.m. glucagon (1 amp) and continue sampling. Take further samples for GH, cortisol and glucose at 90 and 120 minutes. There must be at least 2 specimens following adequate hypoglycaemia.

8. At all times a doctor or nurse must be in attendance.

9. If the patient has a hypoadrenal crisis with hypotension then they should be given i.v. 0.9% saline and hydrocortisone.

10. Once test completed, give supervised meal.

11. Patient should not drive for 2 hours after the test.

"SPLIT" COMBINED PITUITARY FUNCTION TEST

This test is no longer used, but the details are kept for historical reasons and for those sitting the part 1 MRCP (!) In patients with prolactinomas, and in some acromegalics with near-normal GH levels, it is useful to monitor the responses to TRH and GnRH alone. This test is only useful after treatment if it is known there was an abnormal test result prior to treatment. In these patients, the test is "split" as follows:

Time	Glucose	TSH	T4	PRL	GH	LH	FSH	Testo/E2	Cortisol
0		Take	Take	Take	Take*	Take	Take	Take
Give GnRH 100 mcg IV bolus and TRH 200 mcg IV over 2 mins
30		Take		Take	Take*	Take	Take
60	Take	Take		Take	Take	Take	Take		Take
Give insulin IV bolus as calculated above.
90	Take				Take^†				Take
120	Take				Take^†				Take
150	Take				Take^†				Take
180	Take				Take^†				Take

*only if an acromegalic with low GH

^†not needed if acromegalic with low GH

INTERPRETATION

The interpretation of the different components of the standard CPT is listed under the insulin tolerance test, the TRH test and the GnRH test.

In the "split" protocol it is possible to observe the isolated response of GH and Prolactin to TRH. In normals the prolactin will rise by 100% of its basal value while in patients with prolactinomas there is frequently a subnormal response. In normals there is a reduction in GH with TRH but there is a rise in 80% of acromegalics. It is only worth using the "split" protocol on a patient following treatment if they were tested by this protocol pre-treatment. The loss of the paradoxical rise to TRH in acromegaly is a good indicator of successful treatment.

ATH 12/89

VISUAL FIELD TESTING (GOLDMANN or HUMPHREYS PERIMETRY)

INDICATION

Before and after pituitary surgery and before and during pregnancy in patients with macroprolactinomas/non-functioning adenomas. It is important to assess the entire visual pathway and patients will require assessment of:

Near and far visual acuity (using Snellen Charts)
Visual field testing (Humphrey or Goldmann Perimetry)

METHOD

All referrals need to be made on the yellow referral forms and faxed to 020 8846 1959. The eye clinic can also be contacted on ext 1132. All patients will initially have Humphrey perimetry which assesses the central 24 degrees of vision. If this is normal they will then proceed to Goldmann perimetry assessing the whole visual field.

Visual field testing is ONLY performed by qualified orthoptists or ophthalmologists. However, we have included the method below for historical interest.

If you are doing it yourself, follow the instructions below.

1. There is an automated Visual field (Allergan Humphrey) testing machine in the eye room of clinic A (room A11). It is computer controlled and fairly user friendly.

2. Switch machine on. It will perform a self test taking about 5 minutes. Once this is complete the computer will ask you several patient details, such as which eye you are testing. These can be easily fed in using the screen touch sensitive pen.

3. Cover one eye with the eye patch present on top of the machine. Place the patient's chin on the rest at the centre of the hemisphere and the head against the upper band. You will need to manually adjust the position of the chin rest (using the rotating control) until the patient, when looking straight ahead, can see a yellow dot.

4. The patient must be given the hand held pushbutton and told to fix on the yellow dot. He must press the button whenever he sees a flash of light anywhere in the sphere. The patient may need his glasses to allow him to see the object.

5. When the patient is ready, simply select "AUTOMATIC DIAGNOSTIC TEST" from the menu. The machine will automatically find the blind spot and proceed to check the entire visual field by flashing lights at random. It will also check that the patient continues to fixate on the yellow dot by occasionally checking his blind spot.

6. When complete, a printout of the field can be obtained. Repeat the procedure for the other eye.

INTERPRETATION

Formal perimetry is highly accurate and reproducible. Field loss is always significant; it can occur as the result of the pituitary tumour or from the treatment of the tumour. If an increasing field loss is noted it is vital that the patient has a CT scan on that admission.

JD and V.Ferguson 7/08.

SUSPECTED CUSHING'S DISEASE

Order 1 vial of CRH for any patient with suspected Cushing’s for their IPSS. Book two admissions at the start (one for midnight cortisol, LDDST, and the second for IPSS), and book the IPSS with James Jackson.

Overnight dexamethasone suppression testing and isolated CRH testing are not used in our department, but the methods are at the end of the section for completeness.

We have found that the combined LDDST-CRH test is less specific than the LDDST, so we do not advocate using this test in the diagnosis of Cushing’s syndrome (Martin et al (2006) JCEM 91(7):2582-6.).

LOW DOSE DEXAMETHASONE SUPPRESSION TEST (LDDST)

INDICATION

Screening test for Cushing's syndrome, especially if the result of the overnight suppression test contradicts other investigations. In women with a high testosterone this test may be used to differentiate PCO and partial hydroxylase deficiencies (CAH) from autonomous androgen secreting tumours.

CONTRAINDICATIONS

Patients on enzyme inducing drugs e.g. anti-convulsants may rapidly metabolise dexamethasone.

Oestrogens (e.g. pregnancy, HRT or COC) may induce cortisol binding protein and artificially increase total cortisol levels.

Care in diabetes mellitus and patients who are psychologically unstable.

PREPARATION

This is usually an inpatient test with no particular patient preparation. Occasionally the test can be done as an outpatient if you believe the patient is likely to have their tablets on time. They need a 9am cortisol at the start and end of the test. The final (8^th) dose is given 6 hours before the final cortisol sample at T=48h. An ACTH should be measured at the start of the test (ie 9AM just prior to the first dose of dexamethasone), but not throughout the rest of the test.

Stop all oral oestrogen therapy 6 weeks prior to test. Patients on sex steroid implants might generate results that are difficult to interpret. Measuring SHBG and CBG might be helpful in this circumstance.

METHOD

1. The patient takes 0.5 mg dexamethasone p.o. at strict 6 hour intervals (i.e. 0900h, 1500h, 2100h and 0300h) for 48 hours.

2. The cortisol (red top), ACTH (purple top) are measured at 0900h (before the first dose of dexamethasone) on the first day (“T=0”) of the test and at 48 hours later (6 hours after the last dose) (T=48). Samples are taken in red top Vacutainers (serum) for cortisol and purple top tubes on ice for ACTH. The red topped sample can be used to measure SHBG and CBG if needed.

3. A total of eight doses of dexamethasone should be written up (9am, then 3pm, 9pm, 3am, 9am, 3pm, 9pm, 3am.

INTERPRETATION

If the 0900h cortisol (“T=48”) value is less than 50nmol/l the patient has shown suppression. Failure to suppress is seen in the autonomous secretion of cortisol found in Cushing's syndrome. However, since there are several common conditions associated with impaired cortisol suppression following a LDDST (eg morbid obesity, depression), the result should always be interpreted in conjunction with the degree of clinical suspicion.

In virilisation from PCOS or partial hydroxylation deficiencies there will be complete/partial suppression of testosterone. This is not seen in ovarian or adrenal tumours.

SENSITIVITY AND SPECIFICITY

Suppression in patients with Cushing's syndrome is rare (2-5%). Some reported cases metabolise dexamethasone slowly and so achieve higher circulating levels than expected. This test is more specific than the overnight suppression test with a lower false positive rate. Failure of suppression in patients may be seen in patients with systemic illness, endogenous depression, or on enzyme inducing drugs e.g. phenytoin or rifampicin.

REFERENCES

Crappo A., Metabolism 28, 955-979 (1979). Yanovski (1993) : JAMA: 269(17): 2232-2238

Newell Price: Endocrine reviews: 19(5): 647-672.

ATH 11/89, KM 07/02, KM 01/03, NMM 07/08

BILATERAL SIMULTANEOUS INFERIOR PETROSAL SINUS SAMPLING (IPSS) WITH CRF

INDICATION

Patients with Cushing's syndrome and high ACTH levels in whom there is not a clinically definite pituitary source. The aim of this test is to differentiate pituitary from a non-pituitary source of ACTH and to lateralise a corticotroph adenoma.

CONTRAINDICATIONS

(Discuss with interventional radiology x34943)

Allergy to contrast dye.

Ischaemic Heart Disease.

Orthopnoea.

Bleeding tendencies (severe).

PREPARATION

If patient on aspirin/clopidogrel, discuss with radiology.

Metyrapone and ketoconazole need to be stopped 1 week before IPSS.

Order synthetic human CRF in advance from Pharmacy (allow 5 days). DDAVP (10 micrograms IV) is a poor but possible alternative if CRH is not available. Document (in the notes) what type of CRH is being used.

Warn endocrinology lab (34681) 48 hours in advance and on the day of the procedure. If no answer, contact the Duty Biochemistry via Switchboard.

Consent patient (risks of bleeding from cannula sites, CVA, dye allergy, pulmonary embolus). This should be performed by the radiologists.

The day before the procedure, check FBC, U + E, INR, G + S.

Fast for at least 4 hours.

2 people to attend to assist sample processing.

18 red Vacutainers.

18 EDTA Vacutainers, labelled before the study.

Syringes for sampling and flushing cannulae.

Ice.

Arrangements to transfer for immediate centrifugation.

SIDE EFFECTS

CRF can cause flushing and hypotension but this is rare with 100 mcg.

No complications of IPS sampling have been reported in over 50 patients reported in the literature, but we have had one patient who had a pulmonary embolus following the procedure and one who became asystolic during the procedure, but recovered when the procedure was abandoned.

METHOD

1. One catheter is placed in each inferior petrosal sinus (IPS) and their position confirmed on screening. A third catheter is placed peripherally (P) in the arm.

2. Two baseline samples are taken at approximately -5 and 0 minutes. Ask the radiologist for 10 ml from each site: one purple for ACTH and one red Vacutainer at each site. At T = 0 the CRF is injected intravenously as a bolus over 1 minute peripherally. For adults the dose is 100 mcg or 60mcg per square meter body surface in children.

3. Simultaneous samples from the 3 sampling sites are taken at T = 2, 5, and 10 minutes. At the same time as one of the sets of basal samples an arterial sample may be taken from the femoral artery if a pulmonary source of ACTH is possible, and peripheral samples may be taken at T = 60 and 90 minutes (see below). Only samples taken for ACTH should be stored in ice and spun within 15 minutes.

4. ACTH is measured in all samples. Cortisol is measured in the basal samples from all sites and in all the peripheral samples. Prolactin is measured in both IPS series.

INTERPRETATION

· A basal IPS:P ratio ³ 2.0 indicates a pituitary source with 95% sensitivity and 100% specificity. A CRH stimulated ratio ³ 3.0 increases the sensitivity to 100%, the 2 and 5 minute samples usually being sufficient. Pituitary ACTHomas are usually paramedian or lateral and there is suppression of the normal corticotrophs on the contralateral side (Crooke cell changes).

· If in addition the basal or stimulated ACTH level for one IPS sample is 1.5 times as high as the simultaneous contralateral side, this localises the pituitary tumour to the ipsilateral side with a sensitivity of 99% and a specificity of 82%. It has also been reported that prolactin and GH are often raised on the side of the tumour and that this is augmented by CRF.

· In IPS sampling the principal difficulty arises from the positioning of the sampling catheter. Jugular venous samples do not consistently show lateralisation. The measurement of prolactin can be used as a marker of proximity to the pituitary.

· Using the peripheral samples it is possible to look at the response to CRF of venous levels of Cortisol. The interpretation of this response is difficult but in general patients with Cushing's disease tend to have an exaggerated response (>850 nmol/l) and ectopic ACTH sources have a reduced response. The interpretation of the CRF test at present is uncertain as the reported series use different end points, varying doses of CRF and small numbers of patients. Until there is more local experience (see above) of this test it should not be used to differentiate sources of ACTH.

· It appears that in ectopic ACTH production a cortisol response greater than normal has not been described. It is not a sensitive test as approximately 25% of Cushing's disease do not respond to CRF with cortisol responses greater than normals.

REFERENCES

IPS sampling: Clinical Endocrinology 25, 687-96 (1986).

CRF test: A. Grossman et al., Clinical Endocrinology 29, 167-178 (1988).

Petrosal sinus sampling: NEJM 325, 897-905 (1991).

ATH; PJH 8/92.; KM 07/02

HISTORICAL INTEREST

HIGH DOSE DEXAMETHASONE SUPPRESSION TEST (HDDST)

INDICATION

Patients with definite Cushing's syndrome of unknown aetiology.

The pre-test probability of ACTH-dependent Cushing’s syndrome being secondary to Cushing’s disease is 85-90%. The HDDST correctly identifies 69% of patients as having Cushing’s disease. Since the diagnostic accuracy of this test in identifying Cushing’s disease is less than the pre-test probability of making this diagnosis; we rarely use this test now. If ACTH-dependent Cushing’s syndrome has been diagnosed following a LDDST, patients can move straight to IPSS to exclude an ectopic source of ACTH.

CONTRAINDICATIONS

Patients on enzyme inducing drugs e.g. anti-convulsants may rapidly metabolise dexamethasone.

Oestrogens (e.g. pregnancy, HRT or COC) may induce cortisol binding protein and artefactually increase total cortisol levels. Take care in patients with severe depression or hypomania.

PREPARATION

Stop all oral oestrogen therapy 6 weeks prior to test. Again implants can cause problems.

This is an inpatient test and should only be performed after at least 2 baseline values for 24 hour urinary free cortisol and 0900h cortisol and ACTH levels (see below).

METHOD

1. This test often follows the LDDST. The final sample from the LDDST (2+48) can often be used as the basal sample for this test. Basal 0900h cortisol (red top Vacutainer) and ACTH (purple tops Vacutainers on ice) are measured (“8+0”).

2. During the test the patient takes 2 mg dexamethasone p.o. at strict 6 hour intervals (i.e. 0900h, 1500h, 2100h and 0300h) for 48 hours.

3. The cortisol and ACTH are measured at 0900h on the first day of the test and 48 hours later (“8+48”). In some patients the dexamethasone may be continued for 72 hours in which case an additional 0900h serum cortisol and ACTH are taken (“8+72”).

INTERPRETATION

If the 0900h cortisol is less than 50% (some say 90%) of the basal value after 48 hours of dexamethasone this is classified as showing suppression. Suppression with high dose dexamethasone is usually seen in Cushing's disease but not in ectopic ACTH production or adrenal tumours.

SENSITIVITY AND SPECIFICITY

The high dose dexamethasone test is useful but not totally reliable in the differential diagnosis of Cushing's syndrome as it is neither very sensitive nor specific. Suppression occurs in 75% of patients with Cushing's disease, 10-25% of patients with ectopic ACTH and 0-6% of patients with adrenal tumours. Patients with ectopic ACTH who show suppression tend to have occult and relatively benign tumours with lower levels of ACTH and cortisol. These patients are very hard to differentiate from Cushing's disease.

The 0900h cortisol after 48 hours is considered to be the best parameter to use to discriminate between Cushing's disease and ectopic ACTH. The criterion of 50% suppression at 48 hours should not be applied too rigidly as many cases of Cushing's disease will suppress by 40 or 45% or suppress after 72 hours. In difficult cases it is advisable to repeat the test as no patients with an adrenal tumour have been shown to have reproducible suppression and cases of Cushing's syndrome may show cyclical variation.

REFERENCES

Crappo A., Metabolism 28, 955-979 (1979).

PRE-OPERATIVE PREPARATION OF PATIENTS WITH CONFIRMED CUSHING’S DISEASE/SYNDROME.

If the IPSS confirms pituitary Cushing’s, the patient should be booked for pituitary surgery at Charing Cross in about 6 weeks. The merits of starting each patient on cortisol-lowering medication should be discussed first, preferably via the pituitary MDT, since these agents may make early post-operative assessment of cortisol difficult. Decision will be based on the size of the tumour, how clinically Cushingoid the patient is and how quickly Nigel Mendoza can operate. For adrenal tumours or patients undergoing bilateral adrenalectomy as primary treatment, all patients will need at least 6 weeks of cortisol lowering medication pre-operatively aiming for a serum cortisol of 150-300 nmol/L.

First-line medical treatment to lower cortisol is ketoconazole (200mg bd). Monitor cortisol and LFTs weekly. If cortisol >300 nmol/L, double ketoconazole to 400 mg bd. A week later, add metyrapone 250 mg tds, if cortisol >300 nmol/L. Metyrapone can be increased up to 750 mg tds. The side effects of metyrapone are nausea, hypertension and ankle swelling (due to mineralocorticoid effects of 11-deoxycortisol), and hirsutism (if long-term).

If required, etomidate at subhypnotic doses (2.5-5 mg/hr IV) can be used to control cortisol levels, but this requires supervision under ITU. Aim for cortisol of 150-300 nM in the weeks before surgery.

PERIPHERAL VENOUS SAMPLING FOR SOURCES OF ECTOPIC ACTH

This is no longer performed at Hammersmith in view of its low sensitivity.

OVERNIGHT DEXAMETHASONE SUPPRESSION TEST

INDICATION

Initial screening test for Cushing's syndrome in a patient with a low clinical suspicion of Cushing’s if it is difficult to admit patient for a standard (48h) low-dose dexamethasone suppression test.

CONTRAINDICATIONS

Patients on enzyme inducing drugs e.g. anti-convulsants may rapidly metabolise dexamethasone.

Oestrogens (e.g. pregnancy, HRT or COC) may induce cortisol binding protein and artefactually increase total cortisol levels.

Urine collection for 24 hr urinary free cortisol must not occur during this test.

PREPARATION

Outpatient test with no particular patient preparation.

METHOD

1. The patient takes 1 mg dexamethasone p.o. at 2300h and the 0900h cortisol is measured the next morning (7 ml clotted blood, in red top Vacutainer).

2. If the patient is collecting a 24hr urine sample for urinary free cortisol this should be completed before taking the dexamethasone.

INTERPRETATION

If the 0900h cortisol value is less than 35 nmol/l the patient has shown suppression. Failure to suppress is seen in the autonomous secretion of cortisol found in Cushing's syndrome. With this cut off, there will be a high false positive rate.

SENSITIVITY AND SPECIFICITY

If there is strong clinical or biochemical evidence for Cushing's syndrome, a formal 48h low dose dexamethasone test should be performed as this is more specific.

Normal subjects rarely (2%) fail to suppress with overnight dexamethasone unless they are depressed (10-50%), obese (10%) or systemically unwell (10-20%).

CRH TESTING (without dexamethasone).

Samples for ACTH should be collected in purple topped EDTA tubes and stored on ice in transit and taken rapidly to the lab to be centrifuged. This test will thus need regular transport to the lab. Samples for cortisol are red topped and can clot.

PREPARATION

Fast from midnight.

Label eight (8) tubes for ACTH (purple top) and eight (8) tubes for cortisol (red top).

Admit Monday 8.30 am. Cannulate and take basal Cortisol and ACTH at 8.30am.

Patient to remain recumbent until 9am (and fasted).

METHOD.

(Two further baseline samples at –15 mins (8.45 am) and 0 mins (9am) for ACTH and Cortisol).

Administer 100 micrograms human CRF at t=0.

Then sample at 15, 30, 45, 60, 90 and 120 mins (final sample 11am: for ACTH and cortisol at all timepoints.).

INTERPRETATION.

A rise in cortisol from basal to peak of >20% suggests a pituitary source.

A rise in ACTH from basal to peak of > 50% suggests a pituitary source.

Ref: Kaye and Crappo (1990). Ann Intern Med. 112: 434-444

A rise by 35% in ACTH at +15 and +30 minutes (mean) in comparison to the basal (-1 and –5 minutes) values suggests a pituitary source. Ref: Nieman etal (1993). JCEM 77: 1308-1312.

Please note that ovine (oCRF) was used in most studies. Human (hCRH) appears less potent, so smaller rises may be acceptable, suggesting Cushing’s disease.

CUSHING’S DAY CURVE

INDICATION

Assessment of control of Cushing’s syndrome on therapy pre-operatively.

Assessment of possibility of early recurrence of hypercortisolism.

CONTRAINDICATIONS

None

SIDE EFFECTS

None

PREPARATION

Stop all oestrogen therapy 6 weeks prior to test.

No hydrocortisone from midday the day before the test (ie omit evening dose day before test and no hydorocortisone on the day of the test)

Non-fasting: breakfast and normal dose of tablets are taken at the usual time.

18-20g cannula.

6 red top Vacutainers.

Syringes.

METHOD

0900h }

1200h } Take blood

1500h } for cortisol

1800h } measurement

(2400h) }

INTERPRETATION

Normal response is a mean serum cortisol between 150 and 300 nmol/l, and should be maintained while patients are awaiting surgery.

Higher levels indicate a need for increased therapy.

Random concentrations of cortisol can also be used on a day to day basis to determine effectiveness of cortisol suppression on medical treatment (with Ketoconazole (up to 400 mg bd), Metyrapone (up to 750 mg tds) or etomidate (3mg per hour by IV infusion).

REFERENCE

Trainer et al., Clin. Endo. 39, 441-443 (1993).

VERSION HISTORY

KM 07/01, NM 9/08

PROLACTINOMAS AND NON FUNCTIONING PITUITARY ADENOMAS

ASSAY PROBLEMS TO BE AWARE OF WITH PROLACTIN

The hook effect: very high levels are subject occasionally to the hook effect, whereby the assay reports a normal prolactin in the presence of extremely high concentrations of prolactin unless the laboratory dilutes the sample.

Macroprolactin: this is defined as circulating prolactin in a complex (most often with IgG) which has a molecular mass of >100 kDa on gel filtration chromatography. This form of prolactin reacts with immunoassays for prolactin (to differing extents depending on the exact assay) and causes elevated prolactin levels. Although macroprolactin is biologically active in vitro, it is thought that it is inactive in vivo as the high molecular weight prevents it from crossing the vascular endothelium. The definitive method of assaying for macroprolactin is gel filtration chromatography. Polyethylene glycol (PEG) precipitation is used routinely as a screening test, although a false-positive for macroprolactin can occasionally occur due to hypergammaglobulinaemia. In the absence of symptoms of hyperprolactinaemia, the patient with proven hyperprolactinaemia due to macroprolactin does not usually require any treatment.

REFERENCE

Fahie-Wilson et al. Macroprolactin; high molecular mass forms of circulating prolactin. Ann Clin Biochem (2005) vol. 42 (Pt 3) pp. 175-92

Ram et al. False-positive polyethylene glycol precipitation tests for macroprolactin due to increased serum globulins. Ann Clin Biochem (2008) vol. 45 (Pt 3) pp. 256-9

DISTINGUISHING PITUITARY MACROADENOMAS SECRETING PROLACTIN FROM NON FUNCTIONING TUMOURS

Non functioning adenomas (NFAs) also might have a high prolactin, as they have the capacity to cause “disconnection hyperprolactinaemia”, where the mass blocks dopamine inhibition of lactotrophs. Such patients (with NFAs) may present with amenorrhea and even galactorrhoea. A retrospective analysis of NFAs in Oxford has shown that the majority of NFAs (98.7%) generate levels <2000 mU/l.

Although macroadenomas secreting prolactin are generally easy to diagnose and to differentiate from NFAs on the basis that they secrete very high levels of prolactin (>2000 mU/l), occasionally it may be difficult to distinguish between the two conditions. The cabergoline suppression test may be useful to distinguish between the two.

REFERENCE

Karavitaki et al. Do the limits of serum prolactin in disconnection hyperprolactinaemia need re-definition? A study of 226 patients with histologically verified non-functioning pituitary macroadenoma. Clin Endocrinol (Oxf) (2006) vol. 65 (4) pp. 524-9

PROTOCOL FOR CABERGOLINE SUPPRESSION

Principle: A marked fall in prolactin following a single dose of bromocriptine or cabergoline suggests a NFA, whereas prolactinomas have a more gradual fall.

1. The patient will be admitted to the Planned Investigation Unit or the McMichael Centre at 8.30 in the morning. Fasting is not necessary. A urine beta-HCG test is mandatory to exclude pregnancy.

2. At 9 am take 10 ml blood for prolactin.

3. Patient to take 0.5 mg of cabergoline.

4. Further 10 ml blood samples for prolactin to be taken at 0.5, 1, 3, 6, 24, 72 hours, 7 days.

5. The patient can go home after the blood test at 6 hours, but will return to have blood samples for prolactin taken at 24, 72 hours and 7 days.

PREGNANCY AND THE PITUITARY

The normal pituitary lactotrophs expand during pregnancy and can push up a NFA towards the optic chiasm, so regular field testing is essential in macroadenomas. Prolactinomas (micro and macro) often grow during pregnancy.

Dopamine agonists can be continued, and in difficult cases up to 1.5 mg cabergoline daily has been used with good effect. This is NOT licensed. Bromocriptine has been around since 1974, and is thus often favoured in pregnancy although cabergoline seems to have fewer side effects. Pituitary expansion continues during breast feeding, and thus full discussion of risks and benefits of breast feeding need to be discussed with the patient.

Currently, patients at 34 weeks gestation can have a trial off cabergoline if they would like to breastfeed. These women need to be told that on stopping their cabergoline, there is a risk of lactotroph enlargement and hence visual field compromise. Therefore they need regular visual fields on stopping the drug and also shortly after delivery, when lactotroph hyperplasia continues as breastfeeding ensues.

If pre-pregnancy imaging suggests there is little space between the tumour and the optic chiasm, an MRI at around 32 weeks gestation may be helpful to guide whether cabergoline could be stopped.

If the decision is taken to stop cabergoline at 34 weeks, perimetry should be performed and reviewed weekly in clinic until delivery and at 2 weeks post-partum.

DOPAMINE AGONIST TREATMENT OF HYPERPROLACTINAEMIA

The three currently licensed dopamine agonists in the UK for hyperprolactinaemia are bromocriptine, cabergoline and quinagolide. All are subject to the side effects of nausea and mood effects (in rare cases, these drugs have caused psychosis and mania).

Bromocriptine: 1.25 mg od, up to 30 mg daily. Most often subject to nausea, this side effect can be minimized by advising the patient to take the medication with a meal.

Cabergoline: 250 mcg weekly up to 4.5 mg weekly (can be given as 1 or 2 doses in the week). Usually the first-line choice. Studies in patients taking higher doses of cabergoline for Parkinson’s disease show an association with valvular heart disease. Studies are underway to evaluate this side effect in patients being treated for hyperprolactinaemia. Please refer all patients on cabergoline for a research echocardiogram to Dr Niamh Martin /Dr Tricia Tan

Quinagolide: 25 mcg nocte for three days, then titrated up by 25 mcg every three days to maintenance dose of 75-150 mcg nocte. Less often used than the others. As it is a non-ergot derived dopamine agonist, this drug has the theoretical benefit that it should not cause valvular heart disease.

VERSION HISTORY

KM, NM and TT 08/08.

PITUITARY TUMOURS

OPERATIVE MANAGEMENT OF PITUITARY TUMOURS

PRE-ADMISSION

Patient should have had:

· Full endocrine assessment.

· Neurosurgical assessment.

· Neuro-ophthalmological assessment including Humphrey fields in previous 6/12

· Baseline investigations:

CT/MRI brain

Free T4, TSH, prolactin, oestradiol (females), testosterone (males), FSH, LH, cortisol, profile.

ECG and CXR if age >60 years.

IGF-1, GH, with oral GTT if clinically indicated

· If prolactinoma confirmed, treat with dopamine agonist drug (eg. Cabergoline), then repeat CT/MRI scan (1-3 months after prolactin normalised or at minimum plateau). Surgery indicated if tumour non-responsive.

· Check TFTs. If patient is hypothyroid need short synacthen test to exclude associated steroid dependency. Replace with T3 20 mcg tds for 4 days pre-op if surgery urgent, or thyroxine if surgery not imminent.

· Cushing’s disease: start patient on cortisol-lowering medication (see section TREATMENT OF PATIENTS WITH CONFIRMED CUSHING’S SYNDROME for medication and how to decide who warrants pre-operative cortisol lowering), titrating to random cortisol 150–300 nmol/).

PRE-OPERATIVE MANAGMENT

· Confirm neurosurgical operating date (day 0) with consultant neurosurgeon, Mr. Nigel Mendoza (Day 0, Usually a Thursday). If surgery is on Wednesday, call this day –1, so that the protocol below is not affected. (Thursday remains day “0”). If surgery is on Friday, treat this as “day 1” and proceed directly to dexamethasone over the weekend.

· Admit 1-2 days pre-op. (Surgical decision).

· For trans-cranial surgery: dexamethasone 4 mg qds, start 1 day pre-op.

· For trans-sphenoidal surgery:

Hydrocortisone 100 mg i.m. qds starting with pre-medication. (An IV infusion of 4.2 mg per hour (100 mg over 24 hours) is an alternative).

HYDROCORTISONE REPLACEMENT PRE- AND POST-PITUITARY SURGERY

· Peri- and post-operatively, use pre-filled drugs chart available on neurosurgical ward and via http://www.meeran.info.

· Only proceed to oral hydrocortisone if tolerating oral intake. If not, patient will need to stay on im/iv infusion hydrocortisone until eating and drinking properly.

Surgical protocol

Thursday (operative day) 50mg hydrocortisone qds im

Friday (post-op day 1) 50mg hydrocortisone tds im

Saturday (post-op day 2) Oral hydrocortisone 20mg 9am, 10mg 12 midday, and 10mg 4pm

Sunday (post-op day 3) Oral hydrocortisone 10mg 9am, 5mg 12 midday.

Monday (post-op day 4) Switch via coding to endocrine team rather than neurosurgical team (Mendoza to Meeran, neurosurgical team to trigger)

9AM serum cortisol sample (done by Endocrine F1/F2)

RED topped tube

09.00 am serum cortisol sample (done by Endocrine F1/F2). RED topped tube. Call CXH duty Clinical Biochemist on bleep 8256 (telephone 30348) to warn of sample coming. Mark as URGENT and deliver to lab on First Floor. Hand over sample to staff (do not leave in basket outside) and tell them ‘urgent for cortisol as discussed with Duty Clinical Biochemist’.

For all post-op pituitary patients EXCEPT those with Cushing’s disease, once 9AM cortisol sample taken, if delay in accessing cortisol result, patient can be re-started on hydrocortisone whilst awaiting confirmation of 9AM cortisol with plans to formally assess at 6 weeks post-operatively (see below).

Interpretation of results:

Interpretation of cortisol result from day 5 (post-operative day 4): If cortisol >350 nmol/l, then can be sent home without hydrocortisone (ie 10/5/5mg).

If 300-350 nmol/l, then use clinical grounds and pre-op assessment.

If < 300 nmol/l, then continue hydrocortisone.

Sick day rules and steroid card for all patients discharged on hydrocortisone.

6 week post-operative insulin tolerance test/ glucagon stress test to be arranged for all post-operative pituitary patients unless 9AM cortisol <100nmol/L (then to stay on hydrocortisone life-long).

TFTs and oestradiol/testosterone levels may not be interpretable for at least 6 weeks post-operatively. Therefore, ALL patients attending for a post-operative ITT/glucagon stress test should have baseline anterior pituitary function tests, including testosterone/oestradiol, FSH, LH, TFTs (fT3, fT4, TSH – this may be difficult to interpret).

NMM 07/08

POST OPERATIVE MANAGEMENT OF DIABETES INSIPIDUS

· Fluid balance charts should be kept. A spot urine osmolality is checked every 4 hours.

· If urine output >1l per 4 hrs consider desmopressin (adult dose 0.5-1.0 mcg s.c. q6h). Prior to administration check paired plasma and urine osmolality.

· DI is confirmed by the presence of a high plasma osmolality (>295) in the presence of an inappropriately low urine osmolality (U:P ratio <2:1). (urine SG < 1.005).

· If the plasma osmolality is low the patient may be over-drinking due to a dry mouth. A low urine osmolality is appropriate.

IMMEDIATE POST-OPERATIVE ASSESSMENT OF GH BURDEN IN ACROMEGALY

Post-operative assessment of acromegaly

Caution should be made in interpreting GH levels early post-operatively in those patients receiving pre-operative depot somatostatin analogues.

Background

Thursday (operating day)

Friday (post-op day 1)

Saturday (post-op day 2)

Sunday (post-op day 3)

Monday (post-op day 4) GH day curve

Tuesday (post-op day 5) OGTT

NB IGF-1 may not fall until 6 weeks post-op – so this should be checked when patient attends for post-op ITT/glucagon stress test at 6 weeks post-op (caution with interpretation if on pre-operative somataostatin analogues).

Cure immediately post-op taken as

Mean GH on 5 point GH day curve <1.7 mcg/L (:09:00, 11:00, 13:00, 15:00 and 17:00)

Nadir GH on OGTT <0.6mcg/L (mean GH on OGTT <1.7mcg/L also suggestive of cure)

Although need to document whether pre-operative chance of cure was low eg cavernous sinus invasion etc.

Interpretation of results (if no pre-operative depot somatostatin analogue):

1) Mean GH <1.7 mcg/L (day curve, ~ 5mU/L) and nadir <0.6 mcg/L (OGTT, ~ 2mU/L) but IGF-1 above ULN or mean GH >1.7 mcg/L (day curve) and/or >0.6 mcg/L (nadir on OGTT) and IGF-1 in upper half N range - consider medical treatment.

2) Mean GH >1.7mcg/L (day curve) and/or >0.6 mcg/L (OGTT) and IGF-1 above ULN - aggressive treatment (discussion with Mr Mendoza regarding suitability for further re-do surgery).

GH burden should be reassessed using the same OGTT and GH day curve protocol at 6 weeks post-operatively.

If GH undetectable (<0.6mcg/L) with IGF-1 in normal range, measuring random GH and IGF-1 is sufficient for further follow up rather than performing annual OGTTs.

NMM 07/08

IMMEDIATE POST-OPERATIVE ASSESSMENT OF EARLY REMISSION IN CUSHING’S DISEASE

Peri- and post-operatively, use pre-filled drugs chart available on neurosurgical ward and via http://www.meeran.info.

Reduction of cortisol pre-operatively:

· This will depend on size of tumour and clinical assessment of patient (ie extent of Cushing’s clinically). Not all patients will automatically start metyrapone/ketonconazole (can make early post-op assessment of cortisol difficult).

· Patients to be discussed on case-by-case basis at pituitary MDT (will also need early neurosurgical date if not for medical treatment pre-operatively).

Surgical protocol

Thursday (operative day) 50mg hydrocortisone qds im

Friday (post-op day 1) 50mg hydrocortisone tds im

Saturday (post-op day 2) Oral hydrocortisone 20mg 9am, 10mg 12 midday, and 10mg 4pm

Sunday (post-op day 3) Oral hydrocortisone 10mg 9am, 5mg 12 midday.

Monday (post-op day 4) Switch via coding to endocrine team rather than neurosurgical team (Mendoza to Meeran, neurosurgical team to trigger)

NO further hydrocortisone to be given until result of 9AM cortisol from today available.

Cortisol results will be ready by 5pm that day

Give hydrocortisone (ie 10/5/5mg) if cortisol <50 nmol/L, otherwise withold.

Will need brief clinical assessment at 5pm that day.

Tuesday (post-op day 5) 9AM serum cortisol sample (done by Endocrine F1/F2)

RED topped tube

Phone CXH duty biochemist on 8256 to warn of sample coming

Mark as URGENT and deliver to lab on First Floor block. Hand over sample to staff (do not leave in basket outside) and tell them ‘urgent for cortisol as discussed with Duty Clinical Biochemist’)

Cortisol results will be ready by 5pm that day

Give hydrocortisone if cortisol <200 nmol/L (ie 10/5/5mg), otherwise withold. Check 9AM cortisol daily whilst planning further management.

ALL PATIENTS TO BE SENT HOME WITH STEROID ALERT CARD

MUST MAKE ARRANGEMENT AT DISCHARGE FOR ALL PATIENTS TO COME BACK TO WARD 8S (PIU) ON POST-OP DAY 11 (WILL USUALLY BE A MONDAY) FOR A FURTHER 9AM CORTISOL MEASUREMENT (PLUS U & Es) . PATIENTS NEED TO OMIT LAST DOSE OF HYDROCORTISONE ON THE DAY BEFORE TEST AND ON THE MORNING OF TEST UNTIL BLOOD SAMPLE TAKEN.

How to interpret day 5 cortisol levels

Day 5 cortisol < 50nmol/L:

Best prognosis for long term remission (10% relapse at 10y), but still will need regular assessment. Discharge on hydrocortisone 10mg/5mg/5mg (plus steroid alert card) and plan for return for 9AM day 11 cortisol (plus U and Es check due to risk of hyponatraemia).

Day 5 cortisol 50-200 nmol/L:

Risk of relapse no greater than for those with day 5 cortisol of <50nmol/L, so no immediate intervention, but will need regular assessment for recurrence. Discharge on hydrocortisone.

Discharge on hydrocortisone 10mg/5mg/5mg (plus steroid alert card) and plan for return for 9AM day 11 cortisol (plus U and Es check due to risk of hyponatraemia).

Day 5 cortisol >200 nmol/L:

Review histology (ie evidence of an corticotroph adenoma), review pre-operative imaging (eg size of adenoma, invasion etc) with regards to whether re-do is likely to achieve cure and discuss with Endocrine Consultant and Nigel Mendoza. It is often worth waiting to see what the day 11 cortisol value is to guide further surgery.

At discharge, patients must be told to omit 4pm 5mg hydrocortisone dose the day before their day 11 9AM cortisol is due.

How to interpret day 11 cortisol levels

Day 11 cortisol <100nmol/L

Start hydrocortisone 10mg/5mg/5mg (plus steroid alert card)

NOT for post-operative ITT/glucagon stress test (ie must remain on hydrocortisone indefinitely)

Day 11 cortisol 100-300nmol/L

Start hydrocortisone 10mg/5mg/5mg (plus steroid alert card) and book formal ITT/glucagon stress test for 6 weeks post-op via PIU.

Day 11 cortisol >300nmol/L

Can stop hydrocortisone. Book PIU admission for cortisol day curve at 4 weeks post-operatively (to assess whether early remission has actually been achieved) and insulin tolerance test/glucagon stress test at 6 weeks post-operatively.

References:

Biller et al Treatment of ACTH-dependent Cushing’s syndrome: a consensus statement JCEM (2008) 93(7):2454-62

ON DISCHARGE

· If needing hydrocortisone, discharge on HC 10mg + 5mg + 5mg. Give steroid alert card and discuss ‘sick day rules’. Patient should be discussed (with histology) at the next available pituitary MDT.

· Acromegaly: Assessment of HPA axis (ITT/glucagon stress test), assessment of GH burden via GH day curve and OGTT (see ‘Post-operative assessment of acromegaly’) performed 6 weeks post-op. Remind patients to omit their pm dose of hydrocortisone the day before their ITT/ glucagon stress test). Hydrocortisone to be resumed after test until results known.

· Cushing’s disease: ALL patients with Cushing’s disease must have a post-operative assessment at 4 weeks, 3-6 months and annually. At 4 weeks and 3-6 months post-operatively, this should include clinical assessment and a cortisol day curve (09:00, 12:00, 15:00, 18:00, mean cortisol should be 150-300nmol/L) (NB this is NOT a hydrocortisone day curve, this is to assess endogenous cortisol production). Planning for a 6 week post-operative ITT/glucagon stress test will depend on the results of 9AM cortisols and days 5, 11 and at 4 weeks post-op.

· ALL post-operative patients MUST have an endocrine OPD arranged on discharge to ensure revision of post-operative assessment occurs.

· Patients on hydrocortisone should be offered an ITT/glucagon stress test 2 years after surgery as there is a chance of recovery of corticotrophs (or recurrence).

AP 01/98, KM 07/01, NMM 07/08

CUSHING’S DAY CURVE FOR ASSESSMENT OF EARLY REMISSION FOLLOWING TRANS-SPHENOIDAL SURGERY FOR CUSHING’S DISEASE

PREPARATION

Last dose of hydrocortisone is taken at midday the day prior to the test. Patients advised to omit hydrocortisone on day of test.

NB This is NOT a hydrocortisone day curve. This is to assess endogenous cortisol production

18-20g cannula.

6 red top Vacutainers.

Syringes.

METHOD

0900h }

1200h } Take blood

1500h } for cortisol

1800h } measurement (OFF hydrocortisone treatment)

INTERPRETATION

Mean cortisol should be 150-300nmol/L.

REFERENCE

Trainer et al., Clin. Endo. 39, 441-443 (1993).

Biller et al Treatment of ACTH-dependent Cushing’s syndrome: a consensus statement JCEM (2008) 93(7):2454-62

VERSION HISTORY

KM 07/01, NMM 9/08

FOLLOW UP OF PATIENTS WITH CUSHING’S DISEASE FOLLOWING BILATERAL ADRENALECTOMY

Prior to bilateral adrenalectomy:

Pituitary MRI (baseline) – if one not done within last 6 months.
Baseline ACTH (ideally at 9AM pre-hydrocortisone) but otherwise random (must document when ACTH measured in relation to hydrocortisone administration).

REMEMBER – ACTH MUST GO IN PURPLE TOPPED EDTA TUBE & SENT IMMEDIATELY TO THE LAB

Post-bilateral adrenalectomy:

Measurement of ACTH within 3 months of surgery: sample taken at 9AM (pre-hydrocortisone) and 2h after morning hydrocortisone.
Greatest risk of corticotroph tumour progression if ACTH >1000ng/L (pre-hydrocortisone) in first year post-adrenalectomy. If ACTH below 300 ng/L in first year, best prognosis.
MRI should be repeated 6-12 months after adrenalectomy and then annually for first 5 years.

Reference:

Assie G et al. Corticotroph tumour progression after adrenalectomy in Cushing’s disease: a reappraisal of Nelson’s syndrome. JCEM (2007) 92(17): 172-179.

NMM 07/08

POLICY ON SPERM STORAGE PRIOR TO PITUITARY RADIOTHERAPY

All male patients should be offered sperm storage prior to pituitary radiotherapy, even if they have oligospermia.

The outcomes of discussions and decisions about sperm storage are included in the patient’s case notes.

Sperm storage cryopreservation is performed via the Andrology laboratory, Hammersmith Hospital – Dr Kevin Lindsay, Principal Clinical Scientist in Andrology.

Contact details 020 8383-4680

Tel Fax 020 8383-3591

For patients proceeding to sperm storage HIV and Hep B&C status must be checked.

However the patient can proceed with sperm storage whilst the virology tests are being processed.

A standard referral letter can be found on http://meeran.info/ under ‘Sperm Banking’

If radiotherapy is planned, male patients should be offered sperm banking prior to radiotherapy.

HYDROCORTISONE DAY CURVE (HCDC)

INDICATION

To establish the correct dose and distribution of hydrocortisone replacement therapy throughout the day.

CONTRAINDICATIONS

None

SIDE EFFECTS

None

PREPARATION

Stop all oestrogen therapy 6 weeks prior to test.

No need to fast.

Take normal morning hydrocortisone and patient should note down actual time taken.

18-20g cannula.

Red top Vacutainers.

Syringes.

METHOD

Take blood at the following times:

· Blood sample on arrival, noting time of sample and time and dose of hydrocortisone.

· Pre lunchtime (2^nd) dose

· 1 hour post lunchtime (2^nd) dose

· pre evening (3^rd) dose

· post evening (3^rd) dose or at 6pm.

INTERPRETATION

Aim for adequate cortisol levels throughout the day (peak <900 nmol/l, trough >100 nmol/l).

As a very rough guide, the values below are what we commonly find. Minor departures do not necessarily need dose adjustment, especially if the patient is well.

morning peak cortisol 500 – 800 nM

lunchtime peak cortisol 400 – 500 nM

post evening dose 300 – 400

Once adequate levels are achieved, this rarely needs to be repeated, unless there is a significant change in other medication (eg. Starting HRT).

VERSION HISTORY

KM 7/00.

GROWTH HORMONE

A WORD ON UNITS

Note that from June 2008, we have changed the GH assay at Hammersmith and Charing Cross to be reported in mcg/L rather than mU/L. An approximation for conversion of mU/L to mcg/L is to divide by 2-3 (2 at lower end of normal, 3 at upper end of normal).

HUMAN GROWTH HORMONE (HGH) PRESCRIBING FOR ADULT ONSET GROWTH HORMONE DEFICIENCY (AOGHD)

The prescription of HGH follows NICE guidelines, (issued August 2003). HGH is recommended if the patient fulfils the following 3 criteria.

1. Confirmed severe GH deficiency, peak GH of less than 9 mU/L (NICE guidelines), which approximates to 3mcg/L, on ITT, or a cross-validated GH threshold in an equivalent test (e.g. Glucagon Stress Test).

2. Perceived Quality of Life impairment, measured using the Quality of Life assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA) questionnaire, score has to be 11 or greater (total of 25 questions).

3. The patient must be on full replacement for any other pituitary hormone deficiencies

Once on a maintenance dose, the patient continues for a 6-month trial period of GH replacement, followed by a repeat AGHDA. If the patient’s score improves by 7 or more (that is a decrease of at least 7), they qualify to continue long term GH replacement. If not then it is recommended to stop.

N.B.

In young adults (<25 yrs, linear growth completed but not reached peak bone mass) with confirmed severe GH deficiency, GH is recommended until peak bone mass is achieved and then reassess as above with AGHDA

Treatment is self administered by a daily subcutaneous injection. Start at a low dose (0.1mg-0.2 mg daily) and titrate up (by 0.1 mg) at monthly intervals, by monitoring IGF-1, and response to adverse effects, until a maintenance dose is achieved, ideally within 3 months. The current median maintenance dose is 0.4 mg daily. We aim for an IGF-1 level in the middle of the reference range (age and sex matched). Women may require a higher dose than men (and higher doses if on HRT). The dose requirement may decrease with age.

If side effects develop, reduce dose by 0.1mg for at least 2 weeks ,then titrate back up according to IGF-1 and symptoms.

The IGF-1 may be within normal range pre GH replacement, and some centres aim for the median or upper half of the normal range on treatment.

Side Effects may include

headache, arthralgia, myalgia, fluid retention, mild hypertension, carpal tunnel syndrome, visual problems, nausea and vomiting, paraesthesia, antibody formation, reactions at the injection site, rarely benign intracranial hypertension (reverses off treatment).

Contraindications for GH

Evidence of tumour activity

Critically ill patients

Known hypersensitivity to GH or any of the excipients

Pregnancy and lactation

Preproliferative or proliferative Diabetic retinopathy

Practicalities re: prescribing GH. (see http://meeran.info/ for guidance)

You need to

1. Patients will discuss various options for administrative device with endocrine nurse. Once patient has decided what device they would like to use, provide the prescription, GH is available from the hospital pharmacy (and not usually the GP as it is a red listed drug).

2.Fax a patient information form to the drug company (who supply syringe etc, and fund first part of treatment)

3.Fax a referral form to the drug company nurse who arranges a home visit to the patient to educate re administering injection

Monitoring of treatment in OPD (see http://meeran.info/ for pro-forma)

BP, IGF-1, glucose monthly
AGHDA at baseline ,once on maintenance dose of GH ( at 3 months usually) and after 6 months trial of GH.
Weight, BMI, waist hip ratio 3 monthly
Lipids and fasting glucose at baseline and at 9 months
Pituitary profile including TFT and Cortisol axis or HCDC at 9 months ( GH replacement may reveal deficiency of T4 or cortisol)
BMD at 2 yrs if osteopenia/osteoporosis pre treatment
MRI pituitary pre treatment ( within last year) and at 6/12 to 1 year post treatment ( depending on previous MRI findings)

EH 08/08

EXERCISE TEST

INDICATION

Used in a child with definite growth retardation preferably as assessed by reduced growth velocity and a random serum growth hormone (GH) of <15 mU/l. It is a physiological screening test used before formal testing of GH secretion (e.g. insulin tolerance test, arginine stimulation test).

METHOD

1. If child has difficult veins, cannulate before the test (butterfly is sufficient).

2. Take blood sample for GH (into a red top Vacutainer) at T = 0.

3. Take child to the outpatients staircase and note the time

4. Child should then run up and down the first flight of stairs, as hard and as fast as possible, for at least 10 mins and until the child becomes breathless and moderately fatigued

5. Take blood sample for GH 30 mins after the onset of exercise

INTERPRETATION

A normal GH response of > 15 mU/l (5.7 ng/ml) absolves the endocrinologist of any further investigation of GH deficiency. It excludes the need for proceeding to the more laborious and hazardous formal tests. A subnormal response (GH < 15 mU/l) means the child should be considered for a formal test though a repeat exercise test may be valuable (see below).

SENSITIVITY AND SPECIFICITY

A child with GH deficiency will not respond to this test. The percentage of children who are not GH deficient and who show a normal response varies depending on the test used and the peak GH value taken as "normal". Values vary from 68–91%. Repeating the test can also improve the detection rate of normals from 80–92%.

REFERENCE

Milner R.D.G. & Burns E.C., Arch. Dis. Child. 57, 944-947 (1982).

VERSION HISTORY

MLB 12/89

ARGININE STIMULATION TEST

INDICATION

Used in a child with definite growth retardation and a subnormal physiological growth hormone (GH) stimulation test (i.e. GH < 15 mU/l or 5.7 ng/ml).

PREPARATION

Child should be fasting overnight

If the child's bone age is >10 years, the test should be done after sex steroid hormone priming:

M: 100 mg testosterone i.m. 3 days before testing

F: 100 mcg ethinyloestradiol p.o. each for three days before the test.

METHOD

1) Cannulate child.

2) Take blood into a plain tube (red top Vacutainer) for baseline GH measurement (0 mins).

3) Infuse 0.5 g/kg L-arginine monohydrochloride (maximum dose 40 g) as a 10% solution in normal saline over 30 minutes.

4) Take blood for further GH estimation 30, 60, 90, 120 and 150 mins after start of arginine infusion.

INTERPRETATION

· A normal GH response of >15 mU/l (>5.7 ng/ml) excludes GH deficiency.

· A GH response of 7–15 mU/l may indicate partial GH deficiency and should be investigated by a second formal stimulation test.

· A GH response of <7 mU/l (<2.7 ng/ml) should also generally be confirmed by a second test. However, if there are other compatible clinical and auxiliary findings, the child may be directly considered for GH replacement therapy.

· A child with pubertal growth delay may show a subnormal GH response if the test is performed without sex hormone priming. However, there should be a normal response after priming.

SENSITIVITY AND SPECIFICITY

A child with GH deficiency will not respond to this test.

The percentage of children who are not GH deficient and who show a normal response varies from 45 – 93%. Generally, 20% of normal children fail to respond to a formal test and this is the reason for doing 2 tests before proceeding to GH therapy. For example, 71% of normals will respond to both insulin tolerance and arginine stimulation tests. However, the others will respond to at least one test: 13% to insulin, 16% to arginine.

REFERENCE

Raiti et al., Lancet 1183 (1967).

ORAL GLUCOSE TOLERANCE TEST FOR ACROMEGALY

INDICATION

Used where a clinical diagnosis of acromegaly is suspected.

PREPARATION

Fasting from midnight.

18-20g cannula.

6 Red top Vacutainers.

6 grey top fluoride oxalate tubes

METHOD

1. Take blood sample for GH and IGF-1 (into a red top Vacutainer) and glucose (into grey top tube) at T = 0.

2. Administer 75 grams oral glucose in 300 ml water over about 10 minutes.

3. Take blood for GH and glucose at t=30, 60, 90 and 120 minutes.

4. In the occasional patient who needs an OGTT for acromegaly and assessment of their cortisol reserve (NOT in the early post-operative period), a synacthen test can be carried out at the end of this test, with samples for cortisol taken at t=120, 150 and 180. Synacthen 250 mcg is administered at t=120.

INTERPRETATION

In normal individuals, GH levels fall following oral glucose, and at least one of the samples during the test should have undetectable GH levels (ie less than 0.6mcg/L). Failure of suppression or a paradoxical rise in GH suggests acromegaly.

SENSITIVITY AND SPECIFICITY

False positives sometimes occur in patients with anorexia nervosa, or other causes of chronic starvation, although the IGF-1 level is usually normal.

FOLLOW UP FOLLOWING PITUITARY SURGERY AND RADIOTHERAPY

Following irradiation, endocrine testing should be performed on a yearly basis until failure of a cortisol response is apparent for at least 10 years, and then 5 yearly. Once failure is clear, the patient should be put on hydrocortisone replacement and further insulin tolerance tests are not required.

Patients who have undergone pituitary radiotherapy for acromegaly are often on somatostatin analogues following radiotherapy, and once it appears that the radiotherapy has worked, reassessment (OGTT + GH) off these analogues is essential.

SCREENING COLONOSCOPY IN ACROMEGALY

1 Patients with acromegaly should be offered regular colonoscopic screening.

2 The frequency of repeat colonoscopy should depend on the findings at the original screening and the activity of the underlying acromegaly.

3 Patients with an adenoma at first screening or increased serum IGF-1 level above the maximum of the age corrected normal range should be offered screening at three year intervals.

4 Patients with either a negative first colonoscopy or a hyperplastic polyp should be offered screening at five year intervals.

5 Total colonoscopy is required rather than sigmoidoscopy, although the colonoscopy is associated with technical difficulties

6 These patients have increased length of colon, as well as increased circumference. In addition, these patients have colonic transit time that is more than twice that of normal subjects and thus standard bowel preparation is usually inadequate. Therefore, bowel preparation should involve twice the “standard” preparation of PEG-electrolyte solution eg two litres are given at six, four, and two hours before colonoscopy with a liquid only diet for 24 hours beforehand (actual details of bowel preparation should be confirmed according to Trust policy).

Reference:

1. P J Jenkins, P D Fairclough Screening patients for colorectal cancer and polyps in patients with acromegaly. Gut 2002;51(Suppl V):v13–v14

KM/01, NM 7/08

HISTORICAL METHODS OF ASSESSING EXCESS GROWTH HORMONE

FINGER SIZE ASSESSMENT

INDICATION

Finger size is an objective measure of soft tissue over growth. It can be used to follow the response to treatment in Acromegaly.

METHOD

Measurement should be between 0900h and 1000h before any intravenous cannula is inserted. Ring size is assessed on the proximal surface of the proximal interphalangeal joint of the fourth finger. The size is that of the tightest fit. A recording is made from each hand and clearly recorded in the notes. If the finger is too large for size Z then the fifth finger is used.

VERSION HISTORY

ATH 11/89

MEASURING SKIN-FOLD THICKNESS

INDICATION

Skin-fold thickness is used in acromegaly and Cushing's syndrome as an index of skin involvement and therefore disease activity.

METHOD

1. The skin is measured using the skin-fold calliper on the dorsum of the hand over the mid point of the third metacarpal bone.

2. Set the scale on the callipers to zero.

3. Place the patient's hand flat on the table with the wrist in a neutral or extended position.

4. A small skin-fold in the long axis of the hand is lifted up and placed between the blades of the calliper so the fold reaches exactly to the top of the jaw-blades.

INTERPRETATION

· Skin thickness has only a limited role in the diagnosis and the monitoring of acromegaly and Cushing's.

· Mean skin thickness (see reference) in men is 2.8 mm when 20 yrs old decreasing to 1.75 mm when 70 yrs. Women's skin is approximately 0.2 mm thinner than similarly aged men.

· 77% of acromegalics have abnormally thick skin (mean + 2 s.d. in 40 year old males >3.4mm).

· All patients with Cushing's had skin-fold thickness below the mean value but only 42% were abnormally thin (mean - 2 s.d. in 40 year old females <1.5 mm).

REFERENCE

A.D. Wright and G.F. Joplin, Acta Endocrinologia 60, 705-711 (1969).

VERSION HISTORY

ATH 12/89

POSTERIOR PITUITARY

DIABETES INSIPIDUS

WATER DEPRIVATION TEST

INDICATION

Principle: dehydrate till ADH secretion concentrates urine

Used in differential diagnosis of polyuria, separating Cranial Diabetes Insipidus (CDI), Nephrogenic Diabetes Insipidus (NDI) and Primary Polydipsia/Compulsive Water Drinking (PP).

If in the basal state plasma osmolality > 295 mosmol/kg, plasma Na > 145 mmol/l and urine is hypotonic (< 300 mosmol/kg), PP is excluded and investigation goes straight to DDAVP administration.

CONTRAINDICATIONS

Exclude other causes of polyuria: diuretics, chronic renal failure, hypercalcaemia, hypokalaemia, hyperglycaemia. Anterior pituitary hormone deficiency: renders results meaningless as, in particular, steroid and thyroxine deficiencies impair excretion of a free water load.

PREPARATION

THIS TEST SHOULD BE SUPERVISED BY A DOCTOR EG F1 OR F2

Up to 8.30 hrs:

1. No tobacco/alcohol for 24 hrs before the test

2. Stop interfering medication (e.g. DDAVP (last dose 24 hours before the start of the test), diuretics) but not hormone replacement

3. Light breakfast (do not fast or limit fluids overnight).

Equipment:

a) Blood is taken into yellow top Vacutainers, urine into Sterilin universal containers

b) urine measuring jug.

c) scales.

d) DDAVP: if given intranasally, must acquaint yourself with the spray as it is not easy to use.

Supervision by nursing staff or SHO is essential.

SIDE EFFECTS

If true CDI or NDI, risk of excessive dehydration.

METHOD

Stage 1 (exclusion of PP): 8.30 – 16.30 hrs

1. No fluid allowed but dry food permitted (e.g. toast)

2. Weigh patient at time 0 and calculate weight 97% of patient’s weight. Weight should be measured at hourly intervals: stop test if >3% weight loss (positive test)

3. Urine passed and discarded at time 0; urine then passed hourly and hourly volume estimated

4. Urine specimen taken for osmolality from the total hourly sample passed over 8.30 – 9.30hrs (U1), 11.30 – 12.30 (U2), 14.30 – 15.30 (U3), 15.30 – 16.30 (U4)

5. Blood taken for osmolality and plasma sodium at 9.00hrs (P1), 12.00 (P2), 15.00 (P3), 16.00 (P4). Plasma sodium measurement is very important and must be done on ALL blood samples.

6. Note down urine volumes in chart as shown below (U1-U4).

Stage 2 (differential diagnosis CDI from NDI): 16.30 – 20.30 hrs

7. Patient may now eat and drink freely

8. At 16.30 hrs, administer DDAVP: 20 mcg intra-nasally or 2 mcg i.m.

9. Continue to measure hourly urine volumes and take samples for osmolality from each hourly sample. There is no point measuring plasma samples (or taking any blood), as the patient are now eating and drinking freely, and we are only interested in the effects of the administered DDAVP on urine volume and osmolality.

10. Note down urine volumes in chart as shown below (U5-U8).

TIME	URINE / VOLUME	PLASMA
0830	Discard urine
0900	Þ	Collect P1 – osmolality, U & Es
0930	Collect U1 ml
1130	Discard urine
1200	Þ	Collect P2 – osmolality, U & Es
1230	Collect U2 ml
1430	Discard urine
1500	Þ	Collect P3 – osmolality, U & Es
1530	Collect U3 ml
1600	Þ	Collect P4 – osmolality, U & Es
1630	Collect U4 ml
Now give DDAVP i.m. or intranasally
1730	Collect U5 ml
1830	Collect U6 ml
1930	Collect U7 ml
2030	Collect U8 ml

INTERPRETATION

Complete table (see http://www.meeran.info) for urine volumes, weight, urine and plasma osmolalities, plasma sodium to assist interpretation of results.

1) Normal
With dehydration, plasma is concentrated but to <300 mosmol/kg. Urine also concentrates to >600 mosmol/kg.

2) PP or partial DI
Start with a low plasma osmolality, which concentrates to normal during stage 1. Urine concentrates, though may be subnormal response (see below).

3) CDI
Patient excessively concentrates plasma to >300 mosmol/kg with inappropriately hypotonic urine (U3:P3 or U4:P4 = <1.9). After DDAVP: CDI patient, deficient in ADH, is still able to concentrate urine to >150% of previous highest level. In NDI, patient is unable to respond to ADH or DDAVP, and concentrates urine to <150% of previous highest value.

Diagnosis	After dehydration	After DDAVP
Normal	>750	>750
PP or partial CDI	300-750	<750
CDI	<300	>750
NDI	<300	<300

Urine osmolality (mosmol/kg)

Many patients fall in the range 300-750 following water deprivation and it is often difficult to differentiate between PP and partial DI, especially following pituitary-surgery. In this instance, the plasma sodium may be helpful, since in PP, this is often low at the start of the test.

If there is a partial response, this test does not reliably differentiate between PP and partial CDI or NDI because the response to dehydration and DDAVP may be very similar:

· Polyuria of any origin (e.g. PP or CDI) washes out medullary concentration gradient, blunting maximal urinary concentration

· CDI may increase renal sensitivity to very low levels of AVP. If patient has only a partial deficiency of AVP, dehydration may therefore rapidly increase urine osmolality to maximum of which they are capable.

· Some patients with NDI can concentrate urine if plasma AVP increases to supra-physiological levels, e.g. with exogenous DDAVP.

· With PP patients avoid excess water/fluid at discharge as there is a small chance that following ddAVP and subsequent excess water intake of developing hyponatraemia.

IF THERE IS A PARTIAL RESPONSE, FURTHER INVESTIGATION IS INDICATED (see Prolonged Water Deprivation Test below)

SENSITIVITY AND SPECIFICITY

When well performed, the WDT has a sensitivity and specificity of 95% for diagnosing and differentiating severe CDI and NDI. The incidence of false positive and false negative results for PP or partial CDI/NDI is 30-40% (investigate further).

REFERENCE

Vokes et al., Endo. Metab. Clin. N. Amer. 17(2), 281 (1988).

VERSION HISTORY

Revised KM and NM 9/08.

PROLONGED WATER DEPRIVATION TEST (MILLER AND MOSES)

INDICATION

This is only to be performed if there is doubt distinguishing partial DI eg in a patient who has had pituitary surgery, from a patient with psychogenic polydipsia following a standard water deprivation test.

METHODS

Liaise with the Duty Biochemist the day before the test.

The patient must be nil by mouth from 18:00 the day before the test and arrive on Clinical Investigation Unit by 7:45.

Weigh patient at time 0 and calculate weight 97% of patient’s weight. Weight should be measured at hourly intervals: stop test if >3% weight loss (positive test)

Collect urine for osmolality hourly

Collect plasma for osmolality every 2 hours

All osmolalities should be measured immediately (

Water deprivation should be continued until three consecutive urine osmolalities show <30mosm/kg increase (ie has reached a plateau).

When a plateau has been reached, give 2mcg im ddAVP. Patient is then allowed to drink.

INTERPRETATION

1). Normal response: urine osmolality rises to reach a plateau and does not increase further in response to ddAVP. Plasma osmolality is maintained within the normal range. U:P >2 at the end of dehydration.

2). Primary psychogenic polydipsia: before ddAVP urine maximum osmolality >290mOsm/kg with no further rise in urine osmolality after ddAVP. Baseline plasma osmolality is usually low.

3) Partial cranial DI: a rise in urine osmolality of 9% or more after ddAVP suggests partial cranial DI ie endogenous maximal AVP secretion is insufficient to maximally concentrate the urine.

REFERENCE:

1. Adapted from Bart’s Endocrine Protocols

Time	Hours	Urine Osm	Plasma Osm	Weight
08:00	0	U1	P1	yes
09:00	1	U2	-
10:00	2	U3	P3	yes
11:00	3	U4	-
12:00	4	U5	05	yes
etc	etc	etc	etc	etc

THERAPEUTIC TRIAL OF DDAVP

INDICATION

Used when partial response to water deprivation test to differentially diagnose Primary Polydipsia (PP) and partial Cranial Diabetes Insipidus (CDI) or Nephrogenic Diabetes Insipidus (NDI).

SIDE EFFECTS

Water intoxication in PP

METHOD

1. Admit to hospital

2. Monitor daily: fluid input and output, body weight, U+Es and urine osmolality.

3. Patient observed for 2 days and then 10 mcg DDAVP given intranasally od for at least 2-3 days.

INTERPRETATION

· Partial CDI: prompt improvement in thirst and polyuria

· NDI: no effect; can be treated for further 2–3 days with a 10 fold increased dose to see if defect partial or complete

· PP: decreased polyuria with no change in polydipsia. Causes weight gain, increased urine osmolality and progressive dilutional hyponatraemia, which may develop rapidly and severely (hence need for hospitalisation)

SENSITIVITY AND SPECIFICITY

Small possibility of false diagnosis of PP as hyponatraemia may occur in 5% of CDI who continue to drink excessively on DDAVP because of associated abnormal thirst or prolonged habit

REFERENCE

Vokes et al., Endo. Metab. Clin. N. Amer. 17(2), 281 (1988).

MLB 10/89; reformatted BK 7/00.

ADRENAL INVESTIGATIONS

SHORT SYNACTHEN TEST

INDICATION

Used in the diagnosis of hypoadrenalism as a screening test.

It is an increasingly used alternative to the insulin tolerance test to diagnose secondary hypoadrenalism due to pituitary hypofunction. However, it should not be used in the early post-operative assessment of the hypothalamic-pituitary-adrenal axis (an insulin tolerance/glucagon stress test should be used instead).

May also be used to ascertain that the adrenals are functioning normally after a prolonged course of corticosteroids, or after suppression by Cushing’s syndrome (e.g. after removal of a unilateral Cushing’s adrenal adenoma).

Diagnosis and characterisation of 21-hydroxylase deficiency and other causes of adrenal hyperplasia.

Diagnosis of non-classical congenital adrenal hyperplasia in the context of a hyperandrogenic woman, if the morning follicular-phase baseline 17-hydroxyprogesterone is >6.0 nmol/l.

CONTRAINDICATIONS

Definitely not required for assessment of hypoadrenalism if random cortisol > 550nmol/l.

If a random cortisol >450, patients are very likely to pass the test, and some feel that in this circumstance, the test is not usually warranted.

SIDE EFFECTS

None

PREPARATION

If on steroids ensure that none is taken the night prior to the test or on the morning of the test. The final dose of hydrocortisone should be at midday, on the day prior to the test.

HRT or any oestrogen should be discontinued for 6 weeks before the test.

In patients in whom the test is being used to screen for 21 hydroxylase deficiency, the test should be done in the follicular phase because progesterone levels rise substantially in the luteal phase, and there is some cross reaction between the 17 OHP assay and the Progesterone assay.

Admission is required if there is a risk of Addisonian crisis (virtually never).

18-20g cannula

Saline flush

10ml syringes x 4

3 red top Vacutainers for cortisol (same samples for 17-OH progesterone)

1 EDTA tube (purple top Vacutainer) for ACTH basal sample.

1 ampoule of 250 micrograms tetracosactrin (Synacthen)

METHOD

1. 0900h: take 7 ml blood for cortisol (red top Vacutainer) and ACTH (purple top, on ice to lab immediately).

2. Give 250micrograms tetracosactrin IM (ideally) or IV.

3. 0930h: Take 7 ml blood for cortisol.

4. 1000h: Take 7 ml blood for cortisol.

5. For the diagnosis of congenital adrenal hyperplasia the samples taken for cortisol are also analysed for 17-OH progesterone to exclude 21-hydroxylase deficiency. In some cases 17-OH pregnenolone is measured to differentiate between 21-OH and 3ß-HSD deficiency.

INTERPRETATION

Normal response if test done at 0900h (considerable diurnal variation):

Stimulated plasma cortisol >550 nmol/l

Incremental rise of at least 170 nmol/l

· If impaired cortisol response, and ACTH >200 ng/l then diagnosis is primary adrenal failure.

· If ACTH <10ng/l then diagnosis is secondary adrenal failure

· Response of 17-OH progesterone in suspected 21-hydroxylase deficiency (non-classical): marked rise after ACTH stimulation (>30 nmol/l), which varies according to whether the patient is homozygous or heterozygous. Reference for nomogram: New et al., JCEM 57, 320-326 (1983).

SENSITIVITY AND SPECIFICITY

A normal cortisol response does not exclude adrenal failure, since impending adrenal failure might be associated with a much greater loss of zona glomerulosa function. The latter would be suggested by an elevated plasma renin activity.

If equivocal result and no urgency, repeat test after a few weeks.

An abnormal response is consistent with primary or secondary adrenal failure, and should be investigated further. Consider long synacthen test or pituitary function testing.

REFERENCES

Hypoadrenalism

Clayton R.N., BMJ 298, 271-272 (1989).

Burke C.W., Clinics in Endo. Metab. 14, 947-976 (1985).

Adrenal hyperplasia

Savage M.O., Clinics in Endo. Metab. 14, 893-907 (1985).

Azziz et al. J. Clin. Endo. Metab. 78, 810-5 (1994).

VERSION HISTORY

JW 12/89, KM 07/01, TT and NM 8/08

LONG SYNACTHEN TEST

INDICATION

Confirmation of diagnosis of hypoadrenalism.

Differentiating primary and secondary hypoadrenalism (note that measurement of basal 0900h ACTH levels is far more sensitive than cortisol response in the long synacthen test).

The first 3 samples should give the same result as the short synacthen test.

SIDE EFFECTS

None

PREPARATION

Patients who have already been taking corticosteroids should have the last dose 24 hours before the start of the test. Admit the patient if there is a risk of an Addisonian crisis (virtually never). Patients with pituitary disease are usually safe if they have an intact renin-angiotensin (aldosterone) axis. Once the test has commenced, dexamethasone will not interfere with the cortisol result. (Do not use hydrocortisone or prednisolone, which will interfere with the cortisol assay). Use 0.75 mg for 5mg prednisolone equivalent.

1 mg tetracosactrin (depot preparation). This is not the same as ordinary Synacthen!

18-20g cannula.

6 red top Vacutainers.

1 purple top Vacutainer for ACTH.

Syringes.

Saline flush.

METHOD

0900h insert cannula and flush

take blood for baseline cortisol and ACTH

give 1mg depot synacthen i.m.

0930h }

1000h } Take blood

1100h } for cortisol

1300h } measurement

1700h } (i.e. additional 2, 4, 8 and 24h)

0900h }

INTERPRETATION

· Normal response: baseline cortisol >170 nmol/l with rise to >900 nmol/l (peak)

· Samples at 9.00, 9.30 and 10.00 can be interpreted as for a short synacthen test.

· Primary adrenal insufficiency: little or no response

· Secondary adrenal insufficiency: some patients may show a rise in cortisol, which may be delayed (but a subnormal response does not exclude this – measure ACTH levels).

· Patients with a subnormal response can still have their steroids weaned (by 1mg pred per month).

SENSITIVITY AND SPECIFICITY

More sensitive than short synacthen test for primary adrenal insufficiency (for nomogram see Burke et al 1985).

REFERENCE

Burke C.W. et al., Clin. Endo. Metab. 14, 947-976 (1985).

VERSION HISTORY

KM 01/97 updated KM 07/01

ADRENAL TUMOURS

All patients should be referred to Mr Fausto Palazzo, Endocrine Surgeon, at Hammersmith Hospital.

If adrenalectomy is being performed for an adrenal mass associated with Cushing’s syndrome, the patient will need to be treated and well controlled for at least 6 weeks with either metyrapone/ketoconazole. These patients will need to be discussed at the Endocrine MDT

OPERATIVE MANAGEMENT OF BILATERAL ADRENALECTOMY

Discuss with surgeon and/or anaesthetists in advance.

1. Unilateral non Cushing’s (non cortisol secreting) adenomas (eg Conn’s or phaeochromocytomas) rarely need hydrocortisone cover for surgery or cortisol monitoring following an adrenalectomy.

2. Unilateral Cushing’s patients or bilateral adrenalectomy patients will need steroid replacement (see table below). In either case clinical and biochemical monitoring is mandatory.

Traditionally, 100mg hydrocortisone qds has been used for early hydrocortisone cover. However, the majority of patients now undergo laparoscopic rather than open adrenalectomy. Hydrocortisone should be started on induction with either 50 mg qds IM or with an IV infusion of 2.1 mg per hour (write up 50 mg over 24 hours). IV boluses are not appropriate, as the half life of cortisol is short, and plasma cortisol levels fall to undetectable levels in between doses in endocrine patients. These are very different from asthmatics, where IV boluses are given in ADDITION to normal adrenal function.

Start infusion with the premed: hydrocortisone for 24 hrs at 2.1 mg/hr i.v.

Day	Hydrocortisone	Fludrocortisone
0	50 mg/24 hrs IV (2.1 mg/hr) or 50 mg IM qds

Postoperative management

If there are no post-operative complications, the following is a guide to prescribing replacement:

Day	Hydrocortisone	Fludrocortisone
1	50 mg/24 hrs IV (2.1 mg/hr) or 50 mg IM qds	50 mcg p.o. od
2-4	20-10-10mg qds PO	50 mcg p.o. od
5-6	15mg (6am) + 10 mg (noon) + 5 mg (6pm ) PO	50 mcg p.o. od
7+	10mg (6am) + 5 mg (noon) + 5 mg (6pm) PO	50 mcg p.o. od

Cushing’s syndrome caused by a unilateral adenoma can cause suppression of both the pituitary and the contralateral adrenal, and this can take a long time to recover. These patients require synacthen tests before hydrocortisone can be discontinued. Obviously bilateral adrenalectomies will require hydrocortisone and fludrocortisone for life.

Post operatively – if complications:

If on day 1 it appears that patient may need prolonged parenteral hydrocortisone, measure plasma cortisol and adjust dose as necessary.

On discharge

Prescribe the following for eTTAs:

· Hydrocortisone 10 mg / 5 mg / 5 mg

· Fludrocortisone 50 mcg od

Ensure the patient has the following organised:

· They should be given a steroid card and understand ‘sick day rules’ for hydrocortisone replacement.

· An HCDC should be organised at their first clinic visit.

· They need a Medic Alert badge/bracelet: contact details should be given. Bracelet is free if on benefits (£30 otherwise). Full address in index.

HYPERALDOSTERONISM

PLASMA ALDOSTERONE, AND PLASMA RENIN ACTIVITY

INDICATIONS

· Accelerated hypertension.

· Drug resistant hypertension

· Hypertension and adrenal incidentaloma

· Hypertension with hypokalaemia, spontaneous or easily provoked, i.e. by diuretics or sodium loading – consider if plasma potassium is <3.6mmol/L. As the treatment of hyperaldosteronism is far more effective in correcting hypokalaemia rather than the hypertension extensive investigation in normokalaemic patients is not justified.

CONTRAINDICATIONS.

None

SIDE EFFECTS

None

First Line Investigation OF PRIMARY HYPERALDOSTERONISM (CASE DETECTION):

It is important to remember that normokalaemic hypertension constitutes the most common presentation of this disease. Therefore, hypokalaemia alone has a low positive predictive value for primary hyperaldosteronism.

Random plasma aldosterone/renin ratio

Outpatient procedure

Stop beta blockers for 2 weeks prior to the sample, as beta blockers prevent renin release and stop spironolactone 6 weeks before sample.

Other drugs need not be stopped unless further investigations are required (see below)

Supply details of all therapy on request form

Ensure adequate salt intake – NOT loading

Correct severe hypokalaemia (<3.0 mmol/L) first, as a low potassium directly will reduce aldosterone secretion.

Method

Sit patient quietly for at least 10 minutes

1 X Lithium heparin sample (green top vacutainer)

Send urgently to lab (within half an hour) – NO ice needed: Ice will cause cryoactivation (conversion of pro-renin into renin), artificially giving a high apparent renin activity.

Analysis

Carried out in Dept of Chemical Pathology, St Mary’s Hospital

Contact: Mrs Sophie Barnes or Mr Mike Scanlon: Tel. 020 7886 1259

If clinical details and list of medications are provided then St Mary’s are very helpful in supplying a full interpretation of results.

Interpretation of results

Aldosterone/renin ratio

>2000 Conn’s likely if renin £ 0.3 pmol/mL/h

800 - 2000 Possibly Conn’s, investigate further

<800 Conn’s unlikely

For diagnosis of Conn’s: low renin expected

Plasma renin £0.3 pmol/ml/hr (ref. 0.5-3.1)

Aldosterone usually > 350 pmol/L (ref. 100-800) ie. may be normal or high

SECOND LINE INVESTIGATION: CONFIRMATION OF PRIMARY HYPERALDOSTERONISM

Saline infusion test:

Stop spironolactone and epelerone for 6 weeks before the test

Stop beta blockers, calcium channel antagonists, ACE inhibitors and AT2 blockers for 2 weeks before the test.

Can continue to use alpha blockers to manage hypertension eg doxazosin

Ensure plasma K in normal range (ideally >4) prior to performing test

Examine patient for signs of cardiac failure. This test should not be performed in patients with severe uncontrolled hypertension, renal insufficiency, cardiac insufficiency, cardiac arrhythmia, or severe hypokalemia.

Patients stay in the recumbent position for at least 1 hour before test begins.

Cannulate and take blood for plasma aldosterone, plasma renin activity, U and Es.

Infuse 2 litres of 0.9% saline over 4 hours, starting at 9.00 a.m. Blood pressure, oxygen saturation and heart rate are monitored throughout the test. After 4 hours (ie 13:00), take further blood sample for aldosterone, U and Es (IV saline infusion can promote hypokalaemia).

Interpretation

Principle of test is that the lack of suppression of aldosterone excretion with intravascular expansion indicates primary hyperaldosteronism.

Post-infusion plasma aldosterone levels <140 pmol/L (5 ng/dL ) make the diagnosis of primary hyperadosteronism unlikely, and levels >280pmol/ (10 ng/dL) are a very probable sign of primary hyperaldosteronism. Values between 140 – 280 pmol/L (5 - 10 ng/dL) are indeterminate.

References:

Rossi GP et al Prospective evaluation of the saline infusion test for excluding primary hyperaldosteronism due to an aldosterone producing adenoma. Journal of Hypertension 25:1433-1442

Funder JW et al Primary hyperaldosteronism guidelines: Case detection, diagnosis and treatment of patient with primary hyperaldosteronism: An Endocrine Society Clinical Practice Guideline. JCEM Epub ahead of print Jun 13

ADRENAL VENOUS SAMPLING FOR ALDOSTERONE

INDICATION

Once primary hyperaldosteronism has been confirmed biochemically, this allows distinction between unilateral and bilateral disease.

CONTRAINDICATIONS

Discuss with radiologist:

Bleeding tendency.

Accelerated Hypertension.

Allergy to contrast.

Significant ischaemic heart disease.

If patient on aspirin/clopidogrel, discuss with radiology.

SIDE EFFECTS

Bleeding.

Adrenal infarction rarely.

PREPARATION

Remember liquorice ingestion and carbenoxolone may mimic hyperaldosteronism.

Discontinue drugs:

Spironolactone, oestrogens 6 weeks

Diuretics 4 weeks

ACE Inhibitors and NSAIDs 2 weeks

Calcium antagonists 1 week

Sympathomimetics 1 week

Beta-blockers 1 week

If anti-hypertensive therapy needs to be continued then prazosin, doxazosin or bethanidine may be used.

Patient should be on unrestricted sodium intake before admission.

The day before the procedure, check FBC, U + E, INR, G + S.

Consent (risks of bleeding from sheath sites, venous thrombosis). (done by radiology)

Fast overnight.

8 Plain tubes (red top Vacutainers).

Tetracosactrin 250 micrograms (Synacthen).

Arrangements for immediate transfer of samples to laboratory. Two assistants required for this.

METHOD

Catheter inserted via femoral vein and adrenal veins selectively cannulated under X-ray control. Bolus of Synacthen may be given 20 minutes prior to sampling. Samples taken simultaneously for cortisol, DHEAS, androstenedione and aldosterone.

INTERPRETATION

Normal adrenal vein aldosterone 100–400 ng/dl. In aldosterone producing adenoma the ipsilateral value is 1000–10000 ng/dl. Ratio of >10:1 between sides is considered diagnostic.

Confirm that adrenal veins have been cannulated by comparing cortisol and adrenal androgen levels on the two sides.

SENSITIVITY AND SPECIFICITY

The main problem with this procedure is difficulty in catheterising the right adrenal vein, this is because it enters the inferior vena cava at an acute angle and may be multiple. Even in the best hands cannulation is not possible in 26% of patients.

In patients in whom both adrenal veins are successfully cannulated this procedure is 90-95% successful in correctly distinguishing between idiopathic (bilateral) hyperaldosteronism and aldosterone producing adenoma by demonstrating a unilateral increase in aldosterone secretion.

The diagnostic accuracy is improved by measuring Aldosterone/cortisol ratio of the high side divided by Aldosterone/cortisol ratio of the low side. Ratios of >4.0 are diagnostic and ratios >3.0 are suggestive of an aldosterone producing adenoma (APA). (Young et al, Surgery, 2004)

Examples:

	Aldosterone	Cortisol	A/C ratio	Ratio
RAV	870	2432	0.36
LAV	33000	1013	32.6	102
IVC	603	253	2.38

Diagnosis: L sided APA

	Aldosterone	Cortisol	A/C ratio	Ratio
RAV	161000	4130	39
LAV	151000	2100	72	1.8
IVC	57000	2720	21

Diagnosis: BAH

REFERENCES

Young W.F. Jr., Klee G.G., Endo. Metab. Clin. N. Am., 17,2; 367-395 (1988).

Melby J.C., J. Clin. Endo. Met., 69,4; 697-703 (1989).

Postural studies

We are no longer performing these but details are given below for historical interest.

PREPARATION

Remember liquorice ingestion and carbenoxolone may mimic hyperaldosteronism.

Discontinue drugs:

Spironolactone, oestrogens 6 weeks

Diuretics 4 weeks

ACE Inhibitors 2 weeks

NSAIDs 2 weeks

Calcium antagonists 1 week

Sympathomimetics 1 week

Beta-blockers 1 week

If anti-hypertensive therapy needs to be continued then prazosin, doxazosin or bethanidine may be used.

Patient should be on unrestricted sodium intake before admission – in general the salt intake in this part of the world is adequate and patients do not require salt-loading prior to investigation.

Syringes.

A 18-20g cannula.

Saline flushes.

2 EDTA tubes (purple top Vacutainers).

2 Lithium heparin tubes (green top Vacutainers).

Plain 24 hour urine collection bottle for urinary aldosterone.

METHOD

Day 1		Place on liberal sodium intake – 100 mmol/day (e.g. sodium chloride tablets 2g p.o. tds) or ask dietician Take blood for electrolytes – get results on same day. If potassium is low (<3.5 mmol/l) then give oral potassium supplements. Discuss diet with dieticians.
Day2	0700h	Cannulate peripheral vein. Tell patient to remain in bed until told otherwise.
	0800h	Take blood with patient supine (for at least 30 mins) for: Electrolytes and cortisol. Plasma aldosterone (clotted, red topped sample) Plasma renin activity (Lithium heparin NOT on ice. Take to lab immediately). Plasma ACTH (purple topped bottle on ice). Start 24 hour urine collection for aldosterone. Ask patient to get up and mobilise at least from 11.30 for 30 minutes.
	1200h	Take blood for plasma aldosterone, plasma renin activity.

INTERPRETATION

Primary hyperaldosteronism

Normal ranges

Suppressed upright renin <2.8 pmol/ml/hr

2.8–4.5 pmol/ml/hr upright

1.1–2.7 pmol/ml/hr supine

Raised supine aldosterone >450 pmol/l

100-450 pmol/l supine

variable range upright

· If plasma and urine aldosterone are low then consider other causes of hypokalaemia.

· If aldosterone is raised but plasma renin activity is not suppressed then the diagnosis is likely to be secondary hyperaldosteronism.

· It is possible to differentiate the two main causes of primary hyperaldosteronism on the basis of the response to time and posture. In bilateral hyperplasia there is a >33% rise in aldosterone on rising (at noon) while in an adrenal adenoma there is an anomalous fall in aldosterone.

SENSITIVITY AND SPECIFICITY

The tests have greater than 90% accuracy of correctly diagnosing primary hyperaldosteronism.

The changes with posture may help in the differentiation between adenoma and bilateral hyperplasia but should be interpreted in the light of the results of CT scanning. Interpret results with caution in patients with renal impairment.

REFERENCES

Melby J.C., Clin. Endo. Met. 69,4; 697-703 (1989).

Funder J. W. et al Primary Aldosteronism Guidelines: Case Detection, Diagnosis, and Treatment of Patients with Primary Aldosteronism: An Endocrine Society Clinical Practice Guideline. JCEM. (2008) Jun 13 Epub ahead of print.

JW 11/89; revised BK 7/00. revised EM 07/01, NM 07/08

Selenium cholesterol scanning for Conn’s tumours

INDICATIONS

We are no longer performing this but details are given below for historical interest.

CONTRAINDICATIONS

Caution if diabetic.

PROTOCOL

1. Admit. Start dexamethasone 2mg daily at Day -2, i.e. two days before the injection. Monitor blood glucoses qds. Continue dexamethasone to Day +11.

2. On day 0 nuclear medicine will inject 8 MBq of 75Se Scintadren and image.

3. Start 5mg bisacodyl for 2 days.

4. Discharge home once dexamethasone completed.

5. Nuclear medicine will arrange for further images on Day 4, 7 and 11.

6. A cortisol on any morning should be undetectable if the dexamethasone the previous day is suppressing the HPA axis adequately, and may be useful to check compliance. Without adequate dexamethasone suppression, one can wrongly diagnose bilateral adrenal hyperplasia, which is simply an indication of normal cortisol production. Remember that cortisol secretion rates are 1000 times higher than aldosterone secretion rates, so even a single missed dose of dexamethsone can jeapordise the results.

INTERPRETATION

The images will be reported by nuclear medicine, but a Conn’s tumour should take up label with no uptake on the contralateral side. Bilateral uptake suggests bilateral adrenal hyperplasia.

PHAEOCHROMOCYTOMAS AND PARAGANGLIOMAS

PLASMA/URINE CATECHOLAMINE MEASUREMENT

INDICATION

To diagnose excess secretion of catecholamines in patients with possible secondary hypertension or in patients with paroxysmal sweating, headaches, anxiety and hypertension.

CONTRAINDICATIONS

No absolute contraindications.

SIDE EFFECTS

None.

PREPARATION

Certain drugs can cause elevations of catecholamines: catecholamine infusions, SSRIs and SNRIs, cocaine. Certain drugs can interfere with urine catecholamine measurements: e.g. labetalol elutes close to adrenaline on HPLC. Labetalol, however, does not interfere with plasma catecholamines. Please look at table for further examples.

The patient should be given urine bottles with acid preservative as catecholamines deteriorate without preservative. They should also be given a disposable jug to urinate into and instructions to collect.

Blood for plasma catecholamine measurement needs to be taken into Lithium heparin, kept on ice, spun at 4°C, frozen until assay.

INTERPRETATION

Reference ranges for urine catecholamines:

Noradrenaline <0.500 µmol/24hrs

Adrenaline <0.100 µmol/24hrs

Dopamine <3.00 µmol/24hrs

Plasma catecholamine reference ranges:

Noradrenaline nmol/l Adrenaline nmol/l Interpretation

<3 <0.45 unlikely

3–5 0.45–0.8 low probability

5–7.7 0.8–1.2 medium probability

>7.7 >1.2 high probability

SENSITIVITY AND SPECIFICITY

Urine catecholamines have a sensitivity of 85% and specificity of 86 %. Sensitivity can be improved by repeating the test, traditionally 3 times.

Plasma catecholamines have a sensitivity of 76-81% and specificity of 81-88%. It is therefore not the first-line test for ruling out phaeochromocytoma.

REFERENCES

Peaston RT et al Ann Clin Biochem 2008;45:6-10.

Boyle JG et al. JCEM 2007; 92: 4602-8.

VERSION HISTORY

TT 8/08.

PLASMA/URINE METANEPHRINE MEASUREMENT

INDICATION

To diagnose excess secretion of catecholamines in patients with possible secondary hypertension or in patients with paroxysmal sweating, headaches, anxiety and hypertension.

Measurement of fractionated metadrenalines (normetadrenaline and metadrenaline) in plasma or urine provides the highest diagnostic sensitivities for detection of phaeochromocytoma and paraganglioma.

CONTRAINDICATIONS

No absolute contraindications.

SIDE EFFECTS

None.

PREPARATION

You will need to speak in advance to Oonagh Prendiville or Mandy Donaldson regarding analysis of metanephrines

Before testing, ensure that patients are not taking any medications that could cause false positive elevations in metanephrine levels: sympathomimetics (pseudoephedrine – commonly found in OTC cold medications), tricyclic antidepressants, phenoxybenzamine, calcium channel antagonists.

Selective alpha1-blockers (doxazosin, prazosin, terazosin), beta-blockers, ACE-I, angiotensin II receptor blockers, diuretics appear to be OK.

The urine can be collected in acid bottles in the same bottle as catecholamines. The blood sample is collected as per catecholamines.

INTERPRETATION

Metanephrines are the products of COMT metabolism of adrenaline (producing metanephrine) and noradrenaline (producing normetanephrine). Phaeochromocytomas and paragangliomas frequently overexpress COMT. The product of COMT metabolism of dopamine, 3-methoxytyramine, is not assayed. Fractionated totals (conjugated and free) are reported.

Urine reference range from St Helier’s:

Normetadrenaline <2.5 µmol/d

Metadrenaline <1.2 µmol/d

Total metadrenalines <3.70 µmol/d

SENSITIVITY AND SPECIFICITY

Urine metanephrines have a sensitivity of 96-100% and specificity of 94-97%, i.e. they have a better sensitivity than urine catecholamines and are a better rule-out test.

Plasma metanephrines have a sensitivity of 99% and specificity of 89%. It is therefore not clear whether these have any advantage over urine metanephrines.

REFERENCES

Boyle JG et al. JCEM 2007; 92: 4602-8.

D’Herbomez M et al. EJE 2007; 156: 569.

Eisenhofer G et al. JCEM 2003; 88: 2656-66.

Willemsen JJ et al. Clin Chem 2007; 53: 268-72.

VERSION HISTORY

TT 5/08.

MANAGEMENT OF SUSPECTED PHAEMOCHROMOCYTOMA

Modern non-ionic IV contrast does not cause a significant increase in catecholamine levels, so blockade is usually not necessary for CT scanning. Before any procedures involving manipulation of the tumour:

· Alpha blockade with phenoxybenzamine (0.5 mg/kg i.v. over 2-4 hours in 500 ml 0.9% saline). Complete alpha blockade is achieved with 3 doses over 3 days. Warn patient of side effects of alpha blockade including postural hypotension, nasal stuffiness. Other side effects include post-operative hypotension, peripheral oedema.

· Ensure patients are given crystalloids with alpha blockade (e.g. 0.9% saline).

· Within 24 hours, beta blockade should be commenced with either metoprolol 50 mg tds or propranolol 80 mg tds. Side effects of beta blockade include: cold peripheries, bradycardia, postural hypotension.

· In the event of a crisis, use i.v. phentolamine (0.5–1 mg) boluses, which can be repeated until BP controlled. This works rapidly. If patients are not well filled, this can precipitate severe hypotension and a watershed cerebral infarction. Rehydration with crystalloid must therefore be started at the same time.

REFERENCES

Mukherjee JJ et al. Radiology 1997; 202: 227-31.

VERSION HISTORY

Revised TT 5/08.

PENTOLINIUM SUPPRESSION TEST

This test is nearly obsolete as it is difficult to obtain pentolinium.

INDICATION

To exclude the diagnosis of phaeochromocytoma in patients with hypertension and borderline changes in plasma catecholamines or 24 hour urinary catecholamines.

CONTRAINDICATIONS

No absolute contraindications but beware frail patient and patients with severe coronary or carotid vascular disease.

SIDE EFFECTS

May cause severe transient hypotension.

PREPARATION

Order the Pentolinium from pharmacy (difficult to obtain). It comes as 10 mg/ml.

Stop hypotensive treatment (incuding labetalol) for at least 24 hours before the test, especially centrally acting drugs such as methyldopa.

Fast overnight. (Large meals can cause variation in catecholamines).

Quiet environment.

Sphygmomanometer or Critikon BP monitor.

Cannula, 18-20g.

Ice.

Lithium heparin tubes (green top Vacutainer).

Contact biochemistry laboratory before doing the test, enquire how they would like the samples taken and arrange for their delivery.

METHOD

2. Patient should empty bladder before lying down as they might not be allowed to stand for a while.

3. Insert cannula and flush.

4. Rest for 1/2 hour.

5. Monitor BP and pulse at onset and every time blood taken.

6. Take 2 baseline samples at 5 minute intervals for catecholamines. Blood needs to be taken into Lithium heparin, kept on ice, spun at 4°C, frozen until assay.

7. At time 0, give 2.5 mg Pentolinium i.v.

8. Take blood at one hour.

INTERPRETATION

Pentolinium is a sympathetic ganglion blocker. Normal subjects may show an initially elevated plasma adrenaline and noradrenaline but these will fall to within the normal plasma range with Pentolinium. In contrast the autonomous secretion of a phaeochromocytoma will not suppress.

SENSITIVITY AND SPECIFICITY

This test has a low false positive and false negative rate as determined in series of known phaeochromocytomas and normals but published information is very scanty. The most likely theoretical problem is a fall in plasma catecholamine levels in a phaeochromocytoma patient whose tumour is only secreting episodically.

REFERENCES

Brown MJ et al. Lancet 1981; 1: 174-7

VERSION HISTORY

SGG 1/90; revised BK, KM, RB and JT 7/00.

CLONIDINE SUPPRESSION TEST

INDICATION

To exclude the diagnosis of phaeochromocytoma in patients with hypertension and borderline changes in plasma catecholamines or urinary catecholamine metabolites.

CONTRAINDICATIONS

Frail patient with a history of hypotensive episodes or severe coronary or carotid disease.

SIDE EFFECTS

Hypotension and sedation.

PREPARATION

Order the clonidine from pharmacy (readily obtainable).

Stop hypotensive treatment for at least 24 hours before the test if possible.

Fast overnight.

Quiet environment.

Sphygmomanometer or Critikon monitor.

Cannula, 18-20g.

Ice.

Lithium heparin tubes (green top Vacutainers).

Contact biochemistry laboratory before doing the test, enquire how they would like the samples taken and arrange for their delivery.

METHOD

1. Insert cannula.

2. Rest for 1/2 hour.

3. Monitor BP and pulse at onset and every time blood taken.

4. Take 2 baseline samples at 5 minute intervals.

5. Give, at time 0, 0.3 mg clonidine hydrochloride orally.

6. Take blood for catecholamines at 1, 2, 3 hours. Blood needs to be taken into Lithium heparin, kept on ice, spun at 4°C, frozen until assay.

INTERPRETATION

Clonidine acts via the alpha pre-ganglionic receptors to reduce catecholamine secretion.

In normal patients, should suppress plasma catecholamines to ≤50% baseline and to ≤2.96 nmol/l (500 pg/l). Phaeochromocytoma patients should not suppress (positive result).

SENSITIVITY AND SPECIFICITY

This test is 97% sensitive for phaeochromocytoma, but only 67% specific, meaning that it is a reasonable rule-out test for phaeos but not diagnostic.

REFERENCES

Bravo E.L. et al., New Engl J Med 1981; 305: 623-626

Grossman E. et al., Hypertension 1991; 17:733-741

VERSION HISTORY

SGG 1/90; revised TT 5/08.

GENETIC SCREENING FOR PHAEOCHROMOCYTOMAS

25% of patients presenting with phaeochromocytoma/paraganglioma (PH/PGL) disease have a germline mutation in VHL, c-Ret (MEN 2), NF1, SDH-B and SDH-D. These are inherited in an autosomal dominant fashion. The following clinical details are useful:

· Family history: especially with VHL, c-Ret, NF1, SDH-D. There is genomic imprinting of SDH-D: the disease phenotype is only apparent in patients who have inherited the mutant allele from their father, as a rule (although there is one exception in the literature). Family history may not be apparent in SDH-B disease as it is not fully penetrant.

· Age at presentation: although the age of presentation can be wide (5-69 years according to ENS@T data), the pick-up rate with patients presenting at >50 years with PH/PGL disease is low.

· Bilateral and multifocal disease: bilateral PH disease is associated with c-Ret or VHL disease. Multifocal PGL disease is associated with SDH-B and SDH-D disease.

· Malignancy: defined as metastases to non-chromaffin tissue (e.g. bone, lungs, liver, lymph nodes). This is particularly associated with SDH-B disease.

· Clinical features of neurofibromatosis: NF1 disease is a clinical diagnosis based on the presence of ‘Coast of California’ café-au-lait spots, neurofibromas, Lisch nodules (iris nodules), and axillary freckling. DNA analysis is not routinely required.

· Clinical features of VHL disease: CNS and retinal haemangioblastomas, renal cell carcinomas, pancreatic tumours.

· Clinical features of MEN 2: Medullary thyroid carcinoma, parathyroid hyperplasia (2A), mucosal neuromas (2B), Marfanoid phenotype (2B).

This is the current local policy for referral to the joint Endocrine/Genetics clinic (can be done directly for local patients, for out of area patients, request a referral from the GP):

· Patients presenting with PH/PGL disease ≤50 years old.

· Relatives of an index patient with a known mutation, for screening.

Genetic counseling and sampling will be handled by the clinic.

If you want to screen for VHL, SDH-D and SDH-B directly, a sample can be sent to Birmingham, which screen for all three in a single sample. The cost is £1268 (or £634 for VHL only, and £634 for SDH-B and SDH-D) and samples should be sent to West Midlands Regional Genetics Laboratory, Birmingham Women’s Hospital, Metchley Park Road, Edgbaston, Birmingham. B15 2TG. Tel: 0121 627 2710 Fax: 0121 627 2711.

For MEN 2, details of possible screening services are given in the section on Medullary Thyroid Carcinoma.

REFERENCES

Gimenez-Roqueplo A et al. Clin Endocrinol (Oxf) 2006; 65: 699-705.

Pacak K et al. Nature clinical practice Endocrinology & metabolism 2007; 3: 92-102.

VERSION HISTORY

Revised TT 5/08

MIBG SCAN

INDICATION

The [123]I MIBG scan is a useful, qualitative, method of locating the site of a phaeochromocytoma.

It should not be undertaken without biochemical evidence for a tumour being present (24 hour urine VMA, circulating catecholamines, clonidine or pentolinium test), and should be backed up by ultrasound, CT scanning, and, where indicated, venous sampling. It is particularly useful for extra-adrenal and metastatic or residual phaeochromocytoma.

CONTRAINDICATIONS

No absolute contraindications except pregnancy or its possibility, allergy to iodine.

Caution in any patient with any drug allergies.

Many drugs may interfere with the study – nuclear scanning have a list. These include tricyclic antidepressants, SSRIs, calcium channel antagonists, catecholamine receptor agonists and antagonists, phenothiazines, butyrophenones (e.g. haloperidol etc.), guanethidine and reserpine.

PREPARATION

Liase with nuclear medicine at least 1 week in advance of planned scan.

Avoid IV phenoxybenzamine, although PO phenoxybenzamine is OK.

Thyroid uptake should be blocked by potassium iodide 60 mg bd for 48 hours beforehand and for 5 days afterwards.

METHOD

[123]I-metaiodobenzylguanidine is injected intravenously (this molecule is similar to noradrenaline, transported in similar fashion and stored in catecholamine vesicles). The patient is scanned twice at 24 and 48 hours.

INTERPRETATION

Spots of increased uptake on scanning are the tumours. Most common sites: adrenals, organ of Zuckerkandl (usually pelvis). Tumours can be anywhere from base of skull to bifurcation of aorta. Sometimes found near bladder and rarely in the prostate. May be multiple. If the MIBG is negative but there is compelling biochemical evidence of a catecholamine secreting tumour, consider [18]F-FDG or [68]Ga-DOTATATE PET scanning.

SENSITIVITY AND SPECIFICITY

In patients with a proven phaeochromocytoma but uncertain site the scan has 90-96% sensitivity and 98-99% specificity. More recent data with a large series of patients shows that the sensitivity is only 75%. Tumour detection was lower for extra-adrenal paragangliomas (58%) versus adrenal (85%) phaeochromocytomas.

REFERENCES

Sisson J.C. et al., New Engl J Med 1981; 305: 12-17.

Shapiro et al., Cardiology 1985; 72: suppl. 1, 137-142.

Bhatia K. et al., Clin Endo 2008; preprint before publication (doi:10.1111/j.1365-2265.2008.03256.x).

Win et al., Nuclear medicine communications 2007; 28: 359-63.

VERSION HISTORY: SGG 11/89; revised TT 5/08.

Thyroid and Parathyroid.

Protocol for the post-radioiodine treatment telephone clinic

AIM:

Our aim following radio-iodine treatment is to render patients hypo(eu)thyroid. The purpose of the telephone clinic is to rapidly determine when thyroxine replacement should be started, thus avoiding unnecessary outpatient appointments or leaving patients with untreated hypothyroidism, which has many undesirable effects, including possible worsening of thyroid eye disease. See http://radioiodine.info.

THYROID EYE DISEASE.

Worsening of thyroid eye disease only occurs in smokers. There is thus no indication for the use of prophylactic steroids in non-smokers. Even in smokers, the number of patients needed to treat with high dose steroids (40 mg prednisolone daily for 1 month, then taper) means that there will be many patients given steroids with radioiodine for no benefit. All patients should be referred to Veronica Ferguson if there is any doubt (consultant ophthalmologist at Charing Cross). It is preferable to avoid steroids in the majority, and treat the few who develop worsening eye signs with steroids at that stage. Smokers may have a 25% risk of worsening eye disease however.

WHO IS SUITABLE FOR TELEPHONE FOLLOW-UP?:

This service is only available to patients who;

· Are contactable by telephone during office hours (9am – 5pm).

· Speak reasonable English and are able to follow instructions regarding medications.

· Consent to regular blood tests, preferably at the hospital phlebotomy department.

HOW DO I ARRANGE FOR RADIO-IODINE TREATMENT:

Antithyroid drugs should be stopped as soon as the decision to use radioiodine is made. Ideally they will be stopped for at least a week. If you know roughly when the patient wants radioiodine, further planning can be made. If it is clear that the patient will defer treatment for more than 2 months, then the antithyroid drugs should be continued until closer to the date of RAI. As a guide, the antithyroid drugs should be stopped at least 1 week and at most 2 months before RAI.

Give the patient an appointment for list M30 at Charing Cross Hospital as soon as possible. If you are at Hammersmith, you will need to give the patient an appointment on M30 and also write on the frontsheet for SUE BROWN to actually book this on the Charing Cross system (she normally works at CX, but is based at Hammersmith Hospital on Wednesdays).

Send a referral letter (or fill in web form on http://meeran.info) to:

Radioiodine clinic (c/o Dr. Meeran),

c/o Dept of Endocrinology

9^th Floor, East Wing, Charing Cross Hospital (Fax: 020 8846 1862).

Make sure to include as many contact telephone numbers as possible in the letter.

WHAT IS THE PROTOCOL FOR RADIO-IODINE TREATMENT?:

Day –7	Thyroid function tests. Information session & signing of consent form in Department of Nuclear Medicine, Charing Cross Hospital. Send information letter to patient’s GP. Stop anti-thyroid medication.
Day -3	Start Lithium carbonate (Priadel) 800mg nocte.
Day 0	Thyroid function tests. Lithium level. Radio-iodine treatment.
Week +1	Thyroid function tests. Lithium level. STOP lithium treatment.
Week +3	Thyroid function tests. Lithium level.
Week +6	Thyroid function tests.
Week +9	Thyroid function tests.
Week +12	Thyroid function tests.
Week +14	Outpatient clinic visit.

If the patient agrees to take part in the randomized placebo controlled trial, they might receive placebo instead of lithium. These patients should collect the drugs from Charing Cross pharmacy when they attend nuclear medicine there 7 days before their RAI.

WHAT DO YOU NEED TO GIVE THE PATIENT?:

1. Information sheet on Radio-iodine treatment.

2. Give the patient an appointment for list M30 at Charing Cross. Everything else (below) is for information only, and will be carried out from that clinic.

They will be given:

1. An X-Ray request form to Nuclear Medicine for I-131 Therapy.

2. Seven (7) request forms for TFTs (Weeks –1, 0, +1, +3, +6, +9, +12 as above).

3. 2 request forms for a lithium level (week 0 and +1 as above).

4. A prescription for lithium 800mg (specify Priadel) nocte for 10 days.

5. A prescription for thyroxine 100μcg, NOT to be started until they are telephoned.

6. An appointment for the out-patient clinic, 14 weeks after treatment.

7. Make sure to note the patients’ telephone number in the notes and on the X-Ray form. If they need to ring and enquire regarding results/treatment they should be given the switchboard number and bleep 3509.

WHO WILL FOLLOW PATIENTS UP BY TELEPHONE?:

All computerised results are updated and reviewed on a weekly basis by a designated Endocrine/Clinical Chemistry Specialist Registrar and patients telephoned if they become either biochemically hypo- or hyperthyroid following treatment.

WHAT HAPPENS IF A PATIENT DEVELOPS SIGNIFICANT SYMPTOMS AFTER RADIOIODINE?

If at any stage a patient becomes symptomatic or develops Grave’s opthalmopathy the Department of Endocrinology can be contacted by either the patient or the GP and arrangements made to review the patient urgently at the next outpatient clinic.

WHEN WILL THYROXINE BE STARTED.

Blood samples will be checked on the day of RAI, and 1 week later for lithium levels. Thyroid function tests will also be monitored, but no action taken (as the fT4 may be lowered by the lithium).

When the fT4 falls to 14.5 pM or less, then thyroxine will be commenced by telephone. Samples will be collected at 3,6,9 and 12 weeks, and the patient should see someone at about 14 weeks. If they are still toxic, further telephone appointments can be made at 15, 18 and 21 weeks.

If at review (after 12 weeks), the TSH is still not detectable, then this is either due to excess thyroxine, or due to failed RAI. A FT3>5 suggests autonomy, and the thyroxine should be discontinued. If the FT3<5.0, then the dose of thyroxine can be slowly lowered with 3 weekly phone reviews.

EM 07/01, KM 01/03

Instructions for those running the phone clinic.

Patients will be expecting phonecalls to tell them whether or not to start thyroxine.

First look on computer for results of fT3/ fT4/TSH. Ask someone else to phone for lithium level, and let Dr. Meeran know if they are lithium toxic. Some will have a zero level.

Ask the patient their weight in kilograms (or stone/lbs and convert).

Find out how they feel. Ask specifically about nausea. Check that they have been compliant with the lithium/placebo. How many tablets did they take? Which ones did they miss?

If the patient feels toxic (tremor, tachycardia etc), and the FT4 > 40pM, then suggest atenolol 100 mg daily until next (3 weeks) review, as they might still rapidly become hypothyroid.

If FT4< 14.6, then start thyroxine 100 mcg daily. The patient should have a supply of these at home, and should be able to start these the day you make the phonecall.

After week 12, if TSH suppressed, then check FT3. If FT3>5, then stop thyroxine. If FT3<5, then reduce thyroxine slowly.

This page to be filled in with each phonecall in the thyroid clinic made and stored in the thyroid file.

Name:

Hospital Number:

Date of phone call:

Date of blood test:

Date of RAI:

Weeks since RAI:

Results: FT4

FT3

TSH

Lithium level checked (yes/no). Do NOT get result.

Phone call:

Comments about how patient feels:

Weight of patient (at home).

How many lithium tablets did you take and how many did you forget? Which ones did you forget? (Get exact dates).

Do you smoke ? How many?

What tablets are you CURRENTLY taking:

If fT4 < 14.6pM, then start thyroxine 100mcg daily. Advice given: start thyroxine or wait until further samples taken:

If fT4>30 and patient feels unwell (tremor, tachycardia etc), then consider atenolol 100 mg daily.

After week 12, if TSH suppressed, then check FT3. If FT3>5, then stop thyroxine. If FT3<5, then reduce thyroxine slowly.

Preparation of thyrotoxic patients for thyroidectomy

Patients will ideally be rendered euthyroid before surgery. In all cases, one must always balance the risks of delay against the benefit of being euthyroid pre-operatively. In an emergency, the following combination of drugs can be used to try and achieve this in approximately ten days:

1. Beta blockade. Propranolol 80mg tds is favoured historically. Atenolol 100mg or Nadolol 160mg can be administered only once daily and hence might improve compliance

2. Propylthiouracil 250 mg qds. This is a higher dose than used normally, but in emergency higher doses more frequently are required in view of the fact that the liver increases the metabolism of these drugs. The PTU should be administered an hour before any iodide as the PTU will prevent organification of the administered iodine.

3. An excess of iodide or iodine (KI 60 mg tds or 0.3 ml Lugols iodine tds). Potassium iodide 60mg tds is by far the easiest to administer (ref NEJM 1980 (Vol 302) 883-885)

PENTAGASTRIN TEST FOR MEDULLARY THYROID CARCINOMA

CALCITONIN.

Calcitonin may be secreted by C-cells on the thyroid gland. High levels may suggest medullary thyroid carcinoma. In very early disease (eg on screening for familial syndromes), levels may not be raised, but may be stimulated either by calcium or pentagastrin. It is suggested that borderline baseline levels (which no longer need be fasting) are further investigated by a stimulation test.

INDICATIONS

Suspected medullary carcinoma of thyroid.

Screening of families with medullary carcinoma of the thyroid.

Patients with suspected MEN type 2. Remember to inform the MEN2 registry.

Patients with basal CT level >22.1ng/L (males), >10.8 ng/L (females).

CONTRAINDICATIONS

Allergy/anaphylaxis on repeat administration.

SIDE EFFECTS

Nausea, epigastric discomfort

PREPARATION

Check electrolytes and serum calcium.

Cannula, 18-20g.

Pentagastrin 0.5 mcg/kg body weight.

6 x 7 ml Lithium heparin tubes (green top Vacutainers) with 0.2ml Trasylol added.

Centrifuge.

Ice or facilities to transfer samples immediately to lab

METHOD

1. Patients should be fasted, as food can increase calcitonin.

2. Insert cannula and flush.

3. Take baseline sample for calcitonin.

4. Give bolus i.v. of pentagastrin 0.5 mcg/kg body weight and flush cannula.

5. Take samples at 1, 2, 3, 5 and 10 minutes for calcitonin.

6. Take immediately to lab on ice.

INTERPRETATION

In patients with a stimulated CT 30-100ng/L- follow-up screening recommended.

In patients with a stimulated CT 100-200ng/L- probable C-cell hyperplasia or early MTC.

In patients with a stimulated CT >200ng/L- MTC very likely.

Karges W. et. al. Calcitonin measurement to detect medullary thyroid carcinoma in nodular goitre.

Exp. Clin. Endocrinol. Diabetes 2004;11:52-58

Biegelmeyer et. al. Screening for MTC

Wien Klin Wochenschr (2002) 114/7:267-273

Surgical treatment should be considered especially if there is a family history. Potentially affected family members should be screened biennially until 65.

SENSITIVITY AND SPECIFICITY

Pentagastrin stimulates calcitonin best in medullary carcinoma, whereas calcium infusion is best in normals.

Combining two studies only two out of 25 patients with medullary thyroid carcinoma had normal responses to pentagastrin. Many normals have been described with an exaggerated response to pentagastrin and the reproducibility of this test is poor.

Reference: McLean G.W. et al., Metabolism 33, 790-796 (1984).

CALCIUM INFUSION TEST FOR MEDULLARY CA THYROID

INDICATIONS

Suspected acalcitoninaemia.

Suspected medullary carcinoma of thyroid.

Screening of families with medullary carcinoma of the thyroid.

Patients with suspected MEN type 2.

CONTRAINDICATIONS

Bleeding disorders

SIDE EFFECTS

Unpleasant flushing sensation

No major side effects

PREPARATION

Patient should fast overnight.

Check electrolytes and serum calcium.

Cannula, 18-20g.

Saline flush.

Calcium gluconate 10% (10 - 20 ml required).

6 x Lithium heparin tubes (green top Vacutainer) with 200 µl Trasylol.

Syringes.

Ice and facilities to transfer samples immediately to lab.

METHOD

Insert cannula and flush.

Take baseline sample for calcitonin.

Give calcium gluconate 0.2 ml/kg body weight i.v. over 1 minute.

Flush cannula.

Take samples at 1, 2, 3, 5 and 10 minutes for calcitonin.

Send immediately on ice to the lab for centrifugation and freezing.

INTERPRETATION

In medullary carcinoma of the thyroid there is often a raised fasting serum calcitonin (>90 ng/l) but this may be in the normal range. Provocative tests improve the sensitivity of calcitonin measurement. Normal range for peak calcitonin following calcium infusion is 100 to 200 ng/l

SENSITIVITY AND SPECIFICITY

In the study quoted below 8/12 subjects with medullary thyroid carcinoma had increased responses to calcium infusion. Two of the four who failed to respond had a raised baseline calcitonin. There is a high false positive rate especially in young men. The pentagastrin test is better in this situation.

REFERENCES

Charib H. et al., Mayo Clinic Proc., 62, 373 (1987).

VERSION HISTORY

JW 12/89

The current local policy is referral of anyone in whom a diagnosis of MEN2 is suspected to the joint Endocrine/Genetics clinic (can be done directly for local patients, for out of area patients, request a referral from the GP). Genetic counseling and sampling will be handled by the clinic.

An alternative laboratory for MEN1, and MEN 2 genetic screening runs in Exeter under the auspices of Dr. Andrew Hattersley. Tel : 01392 403089. Fax: 01392 403027. E-mail: A.T.Hattersley@ex.ac.uk:

Screening for MEN1 costs £400, for MEN2a, £250 and for MEN2b, £100. Testing for a known mutation in a family member costs £75 for both conditions. Lab contact: S. Ellard (01392 402910).

A request form is available via http://meeran.info

KM 01/03, NM 9/08

FINE NEEDLE ASPIRATION OF A THYROID NODULE (FNA)

INDICATION

Investigation of thyroid nodule(s). The prime aim of FNA is to exclude malignancy.

METHOD

All thyroid nodules suspicious of cancer should be referred to the Hammersmith Thyroid Clinic (clinic code THCI/THEM) to Prof Graham Williams. Mr Palazzo also has a clinic in parallel with Prof Williams on the same day.

There is also an FNA clinic which you can book your patients in for (clinic code PAL2).

INTERPRETATION AND ACTION (Royal College of Physicians Guidelines)

Thy Grade	Cytological description	Action taken
1	Inadequate for diagnosis – smears must contain 6 or more groups of at least 10 thyroid follicular cells	Repeat FNA to obtain a sample that is adequate for diagnosis.
2	Non-neoplastic – features consistent with a nodular goitre or thyroiditis	Repeat FNA in 3-6 months 2 diagnostic benign results are required to exclude neoplasia. Excision may be recommended in certain circumstances (e.g. strong family history, history of irradiation, male gender, extremes of age and other features suggestive of tumour).
3	Either: Follicular lesions/Neoplasms Hurthle cell neoplasms Or: Cellular atypia which cannot be placed in Thy2 or Thy4	DISCUSS IN MDT Follicular lesions undergo lobectomy +/- complete thyroidectomy if histology proves malignancy. FNA showing atypia should be discussed in an MDT
4	Abnormal, suspicious of malignancy	DISCUSS IN MDT Surgical intervention indicated
5	Diagnostic of malignancy	DISCUSS IN MDT Surgical intervention indicated

HOW TO REFER TO THE WEST LONDON CANCER NETWORK THYROID CANCER MDT

For meeting dates, see: http://www.wlcn.nhs.uk/content/workgroups.asp?workgroup=37&subworkgroup=255

Referral form available from: http://www.imperial.nhs.uk/prd/groups/public/@corporate/@communications/documents/doc/id_011030.pdf

REFERENCES

Royal College of Physicians Guidelines for Management of Thyroid Cancer (2^nd edn. – 2007): downloadable from http://www.rcplondon.ac.uk/pubs/contents/f33a5762-6235-469e-91a5-d47d6ce6e0f6.pdf

VERSION HISTORY

SG 10/89; KM 07/01; TT 8/08.

PERFORMING A THYROID FNA

This is no longer done in the general endocrine clinics at either site as patients are referred to the clinics above. Outlined below is the procedure for historical purposes.

PREPARATION

None

SIDE EFFECTS

Rarely: local bleeding. Avoid by applying local pressure

METHOD

1. Contact cytology department who will come almost immediately and bring their prepared slides.

2. Lie patient in supine position with neck flexed backwards.

3. Insert 25 gauge needle into nodule and aspirate (usually more than one pass). Local anaesthesia is usually necessary. The needle should just be passed in and out. Don't draw back as this results in a bloody tap.

HYPERPARATHYROIDISM

ESTABLISH DIAGNOSIS

· Elevated corrected Ca²⁺.

· Low PO₄^3-.

· Normal alkaline phosphatase.

· Normal or elevated serum PTH.

· Exclude vitamin D deficiency

· High 24 hr urinary Ca²⁺.

· To exclude Familial Hypocalciuric Hypercalcaemia (FHH), the calcium clearance to creatinine clearance ratio should be > 0.01. This is calculated as follows (for easy calculation see http://www.meeran.info for on-line calculator).

Calcium Clearance

[Urine Calcium (mmol/l) x urine volume (ml)] / [ Plasma Calcium (mmol/l) x 1440]

Creatinine Clearance (This may be calculated already)

[Urine Creatinine (mmol/l) x urine volume (ml)] / [ Plasma Creatinine (mmol/l) x 1440]

Plasma creatinine is normally expressed in umol/l and needs to be converted to mmol/l by dividing by 1000.

However, this ratio can be reduced to

Urine Calcium (mmol/l) x [Plasma Creatinine (umol/l) / 1000]

Plasma Calcium (mmol) x Urine Creatinine (mmol/l)

For example

FHH

Urine calcium 1.0 mmol/l Ratio = 1.0 x [130/1000] = 0.0079

Urine creatinine 6.2 mmol/l 2.65 x 6.2

Plasma creatinine 130 umol/l

Plasma calcium 2.65 mmol/l

Primary Hyperparathyroidism

Urine calcium 2.2mmol/l Ratio = 2.2 x [74/1000] = 0.035

Urine creatinine 1.4 mmol/l 3.3 x 1.4

Plasma creatinine 74 umol/l

Plasma calcium 3.3 mmol/l

LOCALISATION OF PARATHYROID ADENOMA

None of the techniques are reliable and often a combination of methods are used.

· Ultrasound of neck.

· Sesta-MIBI scanning.

· ¹²³I and sesta-MIBI double isotope scan (higher sensitivity, ask nuclear medicine).

· MRI of neck.

· CT neck (+ upper mediastinum).

· Selective venous sampling for PTH is not routinely used and reserved for difficult cases. Patient requires hospital admission, and investigation needs to be booked with Dr Jackson well in advance.

· All patients with primary hyperparathyroidism needing surgery should be referred to Mr Fausto Palazzo, Endocrine Surgeon at Hammersmith Hospital.

MANAGEMENT PRIOR TO PARATHYROIDECTOMY

· Usual pre-operative bloods, including U+E, Ca²⁺, PO₄, alkaline phosphatase, albumin.

· Maintain adequate hydration.

· Replace deficit and maintain 3-4 l fluids /day i.v. and then orally if patient able to drink.

· If above measures do not reduce corrected Ca²⁺ <2.8 mmol/l give bisphosphonates (e.g. pamidronate 30 mg in 1l 0.9% saline over 4 hrs). This will not start to work for 24hrs, with maximum effect 5-6 days. Plan in advance to avoid severe post-operative hypocalcaemia.

MANAGEMENT AFTER PARATHYROIDECTOMY

· Enquire for symptoms of hypocalcaemia (paraesthesiae, cramps etc.).

· Trousseau’s and Chvostek’s test daily or whenever blood pressure is checked.

· Daily U+E and corrected Ca²⁺.

· If mild symptoms and corrected Ca²⁺ >1.9 mmol/l, give effervescent Ca²⁺ (Sandocal 1000; two tds suggested).

· If severe symptoms and corrected Ca²⁺ <1.9 mmol/l, give Ca²⁺ infusion (calcium gluconate 15 mg/kg i.v. in 1l 0.9% saline over 4 hours). [1gram which is 10 ml of 10% calcium gluconate in a 70 kg patient. Neat calcium gluconate (10ml 10% can cause necrosis if it extravasates, so either administer it yourself through an obviously patent large venflon, or use a central line). Diluting it in a liter of saline is another option.

· If hypocalcaemia persists, start oral Sandocal 1000 (up to 4 tabs qds might be needed) and introduce alfacalcidol (125 ng od). This is a low dose and patients may require 1 – 2 mcg twice daily eventually.

· The amount of calcium needed depends on how hungry the patients bones are, and initially can be quite large.

· Monitor PTH. If detectable, and parathyroid recovery occurs, try to wean off alfacalcidol. If PTH remains undetectable, it is likely that they will stay on alfacalcidol for life. In that situation, the long term risk is nephrocalcinosis as the calcium-phosphate product will be high. Thus long term aim is for a low-normal calcium.

VERSION HISTORY

AP 1/98 updated SS 07/01

PANCREAS

DIABETES

GLUCOSE TOLERANCE TEST

INDICATIONS

· Suspected diabetes mellitus. An oral glucose tolerance test is not required if the diagnosis of diabetes is not in doubt or if a fasting venous plasma glucose is greater than 7.0 mmol/litre or a random venous plasma glucose is greater than 11.1 mmol/l.

· In acromegaly, to establish the diagnosis and to follow patients after treatment with surgery or irradiation.

· Suspected reactive hypoglycaemia.

CONTRAINDICATIONS

None

SIDE EFFECTS

Nausea and occasional vomiting

PREPARATION

The subject should have been on a diet containing an adequate amount of carbohydrate (250g/day) for at least 3 days before the test

Overnight fast.

75g anhydrous glucose.

Fluoride oxalate tubes x 3 (grey top Vacutainers).

18-20g cannula.

Saline flush.

Syringes x3.

METHOD

· Diabetes

Insert cannula.

Take a baseline glucose at time 0.

Give oral glucose load (75 g anhydrous glucose in 250–350ml water).

Repeat blood samples at 60 and 120 min after glucose load.

· Acromegaly

See under “growth hormone” above.

· Reactive hypoglycaemia

Take blood for glucose AND GUT HORMONES (to measure GLP-1) at -15, 0, +15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270 and 300 min.

INTERPRETATION

WHO (established June 2000) for diabetes and impaired glucose tolerance

Plasma Glucose (mmol/l)	Fasting	2 hrs after glucose load
Diabetes mellitus	³7.0	³11.1
Impaired glucose tolerance		>7.8 – 11.0
Impaired fasting glucose	>6.1 – 7.0
Normal	≤6.1	≤7.8

75 g oral glucose tolerance test.

In the absence of diabetic symptoms at least 2 abnormal values are necessary to establish a diagnosis of diabetes mellitus

Gestational diabetes: women who have IGT in pregnancy should be treated as if they have GDM.

SENSITIVITY AND SPECIFICITY

These criteria were revised by the WHO in 1997 and remain arbitrary. Remember that acute illness (e.g. myocardial infarction) and drugs may affect glucose tolerance.

In acromegaly it is very rare for GH to suppress to the normal range with a glucose load. In fact there is often a paradoxical rise in GH. Some normals especially if stressed do not suppress. The definition of "cure" in acromegaly is very difficult. Patients may show dramatic clinical improvement but not suppress with glucose.

REFERENCES

Keen H., Medicine International May, 2672-2675 (1989).

Diabetes Care, 21 S1, 5-19 (1998).

AUTONOMIC FUNCTION TESTS

INDICATIONS

Suspected diabetic autonomic neuropathy.

Shy-Drager Syndrome.

Suspected autonomic failure from other causes.

CONTRAINDICATIONS

Patients with proliferative retinopathy should not perform the Valsalva manoeuvre because of the risk of retinal haemorrhage.

Atrial fibrillation (tests uninterpretable, except postural hypotension and handgrip tests).

SIDE EFFECTS

None

PREPARATION

Sphygmomanometer.

Mouthpiece to attach to sphygmomanometer (5ml syringe minus plunger).

ECG machine (old fashioned type as long rhythm strips recorded).

Tests of cardiac parasympathetic damage

1. Heart rate response to the Valsalva manoeuvre

Start ECG machine (limb leads only, use lead II)

Patient blows into sphygmomanometer and maintains pressure at 40mmHg for 15 seconds, continue recording for 30 seconds after release of pressure.

Measure shortest R-R interval during manoeuvre and longest after.

Valsalva ratio = longest after/shortest during.

Take mean of three readings.

2. Heart rate variation during deep breathing

Start ECG machine

Ask patient to breathe quietly at a rate of six breaths over one minute (5 seconds in and 5 seconds out).

Mark ECG at start of each inspiration and expiration.

Measure maximum and minimum R–R interval for each cycle and convert to beats/min.

Result is mean difference (max – min) for heart rate during deep breathing.

3. Heart rate response to standing

Start ECG recording with patient lying.

Ask the patient to stand, continue recording ECG for 1 minute.

Measure shortest R–R interval around the 15th beat after standing and the longest around the 30th beat.

Calculate longest/shortest = 30:15 ratio.

Tests of sympathetic damage

Blood pressure response to standing

Measure blood pressure lying and then 2 minutes after standing

Record postural difference

INTERPRETATION

TESTS	Normal	Borderline	Abnormal
Valsalva ratio	≥1.21	1.11-1.20	≤1.10
(max–min) HR	>15	11-14	<10
(30:15 ratio)	>1.04	1.01-1.03	≤1.00
fall in BP	≤10	11-29	≥30

These tests can be used to determine the degree of abnormality present: if two or more of the parasympathetic tests plus the sympathetic tests are clearly abnormal then this indicates significant autonomic damage, earlier damage is signified by abnormalities in at least two parasympathetic tests.

SENSITIVITY AND SPECIFICITY

Caution should be taken in interpreting these tests in patients who are poorly co-operative and in the elderly.

REFERENCE

Clarke B.F. and Ewing D.J., BMJ 285, 918-920 (1982).

GUT HORMONE TUMOURS

INSULINOMAS

Patients with hypoglycaemic symptoms may have an insulinoma or reactive hypoglycaemia should have a prolonged (5 hour) oral glucose tolerance test before their supervised fast. Therefore both protocols are given below. (If both negative, consider EEG and CT brain, as temporal lobe epilepsy also occurs with this presentation).

If the patient is on diazoxide it should be discontinued a week before admission.

GLUCOSE TOLERANCE TEST

PREPARATION

The subject should have been on a diet containing an adequate amount of carbohydrate (250g/day) for at least 3 days before the test thus the OGTT must NOT follow the prolonged fast.

Overnight fast.

75g anhydrous glucose.

Fluoride oxalate tubes x 14 (grey top Vacutainers).

Lithium heparin with trasylol (0.2 ml) x 14

18-20g cannula.

Saline flush.

METHOD

Take blood for glucose AND GUT HORMONES (to measure GLP-1) at -15, 0, +15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270 and 300 min.

PROLONGED SUPERVISED FAST

INDICATION

Used to demonstrate fasting hypoglycaemia and diagnose insulinoma if not shown spontaneously or after an overnight fast.

PREPARATION

Admit to perform test under close supervision with glucose (p.o./i.v.) available.

Leave a copy of this protocol sheet in the nurses’ notes and a copy above the patient’s bed.

METHOD

· Cannulate patient and commence 72 hr fast.

· Water/non-caloric beverages allowed. Patient should be active during waking hours.

· Blood glucoses should be done at regular (4–6 hr) intervals and whenever the patient has symptoms suggestive of hypoglycaemia. Decrease to 2 hr intervals if the patient consistently has glucoses <3.0 mmol/l.

· If blood glucoses are ≤2.2 mmol/l or symptoms are convincing:

- Take blood for glucose, insulin and C-peptide in a plain clotted tube (7 ml) and a fluoride oxalate tube.

- Take blood for sulphonylurea screen in a plain clotted tube (7 ml) (NB urine screen only useful if prolonged delay in obtaining a plasma sample, all sulphonylureas detected on plasma due to improved radioimmunoassay and HPLC. Therefore, urine superfluous nowadays and more interference in urine vs. plasma makes plasma sulphonylurea analysis more specific)

- Take to chemistry labs to be separated and frozen within 30 mins. Ring biochemistry up for an urgent glucose.

- Do not reverse hypoglycaemia until the lab confirms hypoglycaemia, or unless the patient becomes unconscious or fits.

· If no symptoms during the fast, finish with 15-30 mins exercise, e.g. a brisk walk around the hospital.

· Take final samples for glucose, insulin and C-peptide, sulphonylurea screen.

INTERPRETATION

· Normals do not become hypoglycaemic, although young women can run glucoses in the region of 2.2–3.0 without symptoms.

· True hypoglycaemia must be demonstrated (glucose ≤2-2.2 mmol/l), before we are able to either interpret insulin results or consider insulinoma.

· If hypoglycaemia with raised insulin but low C peptide, consider self administration of insulin.

· If hypoglycaemia with raised insulin, and raised C-peptide, make sure sulphonylurea screen is negative! Tel (Guildford lab 01483 571 122 x 4696).

· With hypoglycaemia, insulin and endogenous insulin production (estimated by C-peptide) should be low.

- Insulin >6 mU/l (>50 pmol/l); C peptide >300 pmol/l = insulinoma (check ratio of c-peptide to insulin high enough).

- Insulin >3-6 mU/l (25-50 pmol/l); C peptide 100-300 pmol/l = possible insulinoma but needs further tests

- Insulin <3 mU/l (<25 pmol/l); C peptide <75 pmol/l = normal response

· Ketones should be suppressed with insulinoma even though patient is fasting because of the excess insulin.

SENSITIVITY AND SPECIFICITY

By 24 hrs, 66% insulinomas develop hypoglycaemia and by 48 hrs, >95% insulinomas can be diagnosed. After 72 hrs fast plus exercise, if no hypoglycaemia, insulinoma is very unlikely.

REFERENCE

Friesen, S.R. Surg. Clin. N. Amer. 67(2). 379 (1987).

VERSION HISTORY

MLB & PJH 10/91

MANAGEMENT OF STABLE INSULINOMAS PRIOR TO SURGERY

ALTERNATIVES INCLUDE:

1. Dietician review. Multiple, regular, small meals usually help.

2. Guar gum 5g tds also helps by slowing gastric absorption.

3. Diazoxide 50–200 mg tds, but beware of hypokalaemia and severe oedema

4. NG feeding can be considered.

5. Steroids can help for a short period.

6. Octreotide can be helpful but beware hypoglycaemia if glucagon levels are suppressed.

7. Calcium channel antagonists may be useful for nesidioblastosis.

GASTRINOMAS

GASTRIC ACID SECRETION

INDICATION

Used in the diagnosis of Zollinger-Ellison syndrome. Rarely needed now as an endoscopy can give evidence of acid hypersecretion (multiple ulceration) and usually can distinguish achlorhydria.

Consider syndrome if:

1) Raised gastrin (>40 pmol/l) in the absence of other causes (e.g. H2 antagonists, PPIs, pernicious anaemia, other causes of achlorhydria, renal failure).

2) Associated upper gastrointestinal disease, i.e. peptic ulcer disease with poor response to treatment; multiple duodenal or jejunal ulcers; peptic ulcer disease with unexplained diarrhoea; fulminant peptic ulcer disease (perforation, haemorrhage, oesophagitis and stricture); ulcer in upper part of ligament of Treitz.

Measuring gastric output distinguishes secondary hyper-gastrinaemia (due to achlorhydria) from primary hyper-gastrinaemia. Administration of pentagastrin i.v. does not improve the diagnostic accuracy.

PREPARATION

Book with endoscopy suite since the end couch next to the apparatus will be required.

Liase with Gastro research fellow to ensure that equipment is not being used.

Stop H2 antagonists for 72 hrs and stop PPIs for 2 weeks.

Stop antacids 24 hours before blood sample.

Patient should be fasting.

Check that the autotitrator is available, otherwise you will need to obtain a burette, conical flask, pH meter and 0.1M NaOH.

METHOD

1. Pass the special double lumen naso-gastric tube (obtained from sister in endoscopy) with plenty of Xylocaine spray to the nose and throat, and lignocaine jelly to the nose. Pass the NG tube as far as the 50cm mark at the nostril.

2. Ask the patient to drink 50mls of water and then aspirate this via the NG tube to check that it is in the most dependent part of the stomach.

3. Connect NG tube to the pump and collect four samples of gastric juice, each over 15 min into polystyrene cups. Alternatively, aspirate regularly and periodically with a 50ml syringe to collect gastric juice over each 15 min period.

4. Measure total volume of each sample. Decant 10mls of each into a fresh polystyrene cup and titrate against 0.1M NaOH with the automated titrating equipment, or carry out a standard neutralisation titration manually.

5. Calculate the acid production of each 15 min collection:

A = (N/100) ´ V

A = mmol of acid production

N = volume (ml) of 0.1M NaOH solution needed to neutralise 10mls of gastric juice

V = volume (ml) of gastric juice in 15 min collection

A sum of the acid production for each 15 min will give the total hourly production.

INTERPRETATION

Spontaneous basal acid outputs of 20 - 25 mmol/hr are almost diagnostic, >10 mmol/hr is suspicious. Post ulcer surgery >5 mmol/hr is indicative.

Realistically, basal acid output studies may be complex to perform. An alternative is to take a single gastric pH measurement using a wide bore nasogastric tube and pH (not litmus) paper. A basal gastric pH of >2 virtually excludes a gastrinoma.

SENSITIVITY AND SPECIFICITY

Hypergastrinaemia and raised gastric acid are also found with:

1. gastric outlet obstruction: resolves with NG decompression

2. massive small bowel resection: resolves a few months post op

3. antral G cell hyperplasia: excess cells on histochemistry

REFERENCE

Deveney et al., Surg. Clin. N. Amer. 67(2) 411 (1987).

VERSION HISTORY

MLB & PJH 2/91; corrected equation BK 7/00.

INTRAVENOUS SECRETIN TEST

We do not use this test routinely, but describe it here for historical purposes.

INDICATION

The intravenous secretin test should, whenever possible, be performed only after the results of basal plasma gastrin and acid output – both performed off PPIs for 2 weeks, H2 blockers for 3 days and fasted - are available.

The indications for the test are:

1. Strong clinical suspicion of a gastrinoma with equivocal results of acid studies and fasting gastrin.

2. Inability to wean patients off antisecretory therapy for long enough to perform acid studies and gastrin estimation because of recurrence of severe symptoms.

PREPARATION

Warn fasting gut hormone lab (34549/33949) 48 hours in advance.

Fast overnight. If possible, stop antisecretory therapy for 24 hours.

Secretin (Kabi) ordered in advance from Pharmacy.

7 x 7 ml Lithium Heparin tubes (green top Vacutainers) with 200μl Trasylol labelled before the study.

Syringes.

Ice.

Arrangements to transfer for immediate spinning.

METHOD

1. Site indwelling cannula.

2. Take two baseline samples at T = -15 and 0 mins.

3. Secretin 2U/kg injected as bolus at T = 0.

4. Blood samples taken at T = 2, 10, 15, 20 and 30 minutes.

5. Samples stored on ice and spun within 15 minutes.

6. All samples assayed for gastrin.

INTERPRETATION

The criteria for diagnosing a gastrinoma are based on gastrin assays from other laboratories where results may not be directly comparable. The best criterion is a rise in gastrin of 200 pg/ml – equivalent to about 100 pmol/l. This gives a sensitivity of 85% when performed on all patients with a fasting gastrin of less than 400 pmol/l. A rise of 50% over basal values gives a sensitivity of 78%. Gastrin levels FALL in normal individuals in response to secretin.

Few false positives have been reported, but massive rises occasionally occur in association with achlorhydria and common duodenal ulcer disease, hence the need to have acid studies and fasting gastrin as the initial investigations, if possible.

REFERENCE

Frucht et al., Ann. Intern. Med. 111, 713-722 (1989).

LOCALIZATION OF GASTRINOMAS AND INSULINOMAS

IMAGING.

CT or MRI.

Octreotide scan

Endoscopic ultrasound is performed at the Hammersmith Hospital by Dr Vlavionos Panagiotis.

Preparation for endoscopic ultrasound (EUS)

Patients need to fast from 4 am, but insulinoma patients are at risk of hypoglycaemia and will require admission for an iv dextrose infusion from at midnight.

SELECTIVE ARTERIAL INJECTION

INDICATION

This investigation is performed in conjunction with highly selective angiography for patients with proven gastrinomas or insulinomas, whose tumours are too small (usually less than 1 cm) to be detected by CT or USS. This comprises about 50% of patients with these syndromes. Gastrinomas can be stimulated with intra-arterial secretin or calcium; insulinomas with intra-arterial calcium. Much better results are obtained with calcium, and secretin is no longer really available.

CONTRAINDICATIONS

(Discuss with radiology S.R.)

Allergy to contrast dye.

Ischaemic Heart Disease

Orthopnoea

Bleeding tendencies (severe)

If patient on aspirin/clopidogrel, discuss with radiology.

PREPARATION

Order Secretin (Kabi) or 10% calcium gluconate in advance from Pharmacy.

Warn fasting gut hormone lab (34549/33949) or endocrinology lab (34681) 48 hours in advance.

Stop diazoxide 7 days before procedure. Patients on PPIs or H2 antagonists do not need to be be discontinued (unlike fasting gastrin measurements for diagnosis).

Consent patient (may have flushing, nausea and hypoglycaemia following calcium injection, risks of bleeding from sheath sites, thrombosis/dissection of femoral artery and visceral arteries, dye allergy). This should be done by the radiologist.

Blood for FBC, U+Es, clotting, and G+S should be taken the day prior to the procedure.

Fast for at least 4 hours and run in 5% dextrose to maintain blood glucose at about 3.0 mmol/l.

2 people to attend to assist sample processing.

7 tubes per arterial run (prepare 5 runs and have more tubes to hand):

7 ml Lithium Heparin tubes (green top Vacutainers) containing 200 µl Trasylol marked before the study starts for gastrinoma.

7 ml plain bottles (red top Vacutainers) for insulinoma. (for insulin AND c-peptide).

Syringes.

Ice.

Stopwatch.

Arrangements to transfer for immediate spinning.

SIDE EFFECTS

No serious complications of this procedure have been reported in the 30 patients reported in the literature. Flushing and nausea may follow calcium injection. One of our insulinoma patients had a hypoglycaemic episode following injection of calcium and so BMs should be monitored and the glucose maintained at 3 - 5 mmol/l with dextrose infusion if necessary. The other potential side effects are those of the angiography itself.

METHOD

1. A catheter is placed in the right hepatic vein prior to routine highly selective visceral angiography.

2. Following angiography each artery (usually proximal gastroduodenal, proximal splenic, hepatic and superior mesenteric) is recatheterised in turn, preferably starting with the vessels least likely to be supplying the tumour. Occassionally the dorsal pancreatic artery is also catheterised.

3. Take two baselines at T = -120 and 0 secs.

4. At T = 0 secretagogue is rapidly injected as a bolus into the artery – 30U secretin in 5ml normal saline or 1 ml of 10% calcium gluconate as appropriate.

5. Blood is sampled at T = 30, 60, 90, 120 and 180 secs (give a 10 sec countdown before each sample).

6. Samples for gut hormone assay should be stored in ice and spun within 15 minutes, and samples for insulin assay should be separated within 30 minutes. Do not store insulin samples on ice unless procedure is very prolonged. A Clinical Chemistry form needs to be completed with details of arteries sampled, times and hormones that you want assayed.

INTERPRETATION

· Secretin injection: localization to a specific region of the pancreas or duodenum (regionalization) is based on a gradient of greater than 50% on the 30 sec sample. Using these criteria the NIH group successfully regionalized 54% of tumours and in combination with angiography, 77% of lesions were localized.

· Calcium injection: 4 patients have been reported in the literature (by the NIH group). All were localized using the criterion of a two-fold rise in insulin in the 30 or 60 sec hepatic vein samples. There has also been one report of a PPoma being localized by selective arterial calcium injection.

REFERENCES

Secretin: Doppman J.L. et al., Radiology 174, 25-29 (1990).

Calcium: Doppman J.L. et al., Radiology 178, 237-241 (1991), Fedorak I.J. et al., Surgery 113, 242-249 (1993), O'Shea et al., JCEM (1996): 81(4): 1623-1627

Turner etal (2002): Clin End (Oxf). Calcium stimulation tests for localisation of gastrinoma.

Dhillo etal (2005): Eur. J. Gast Hep.

PJH 9/93; minor corrections BK 07/00, KM 07/02

CARCINOID AND NEUROENDOCRINE TUMOURS

FOODS TO AVOID DURING 24 HOUR URINE COLLECTION FOR 5-HIAA

Avocados, bananas, plums, walnuts, pineapples, tomatoes, aubergines, cough medicine.

HEPATIC EMBOLIZATION OF METASTASES

DEFINITION

The liver has a dual blood supply (hepatic artery and portal vein) so that interruption of hepatic arterial supply by its embolization using foreign substances (e.g. polyvinyl alcohol) in the presence of a patent portal circulation (necessary to sustain liver function). Undertaken under local anaesthetic by Professor Jackson's radiology team.

INDICATIONS

1. Palliation of clinical consequences of hormone production from hepatic secondaries in the carcinoid syndrome and other neuroendocrine tumours. Diagnosis should be fully established.

2. More controversially: reduction of tumour load in these patients to improve the well being of the patient or to reduce local symptoms (e.g. "dragging" abdominal pain from hepatomegaly).

CONTRAINDICATIONS

Prolonged prothrombin time

Non-patent portal circulation

Obvious end-stage illness

Ischaemic heart disease

Contrast allergy

Discuss patients on aspirin/clopidogrel with radiology

SIDE EFFECTS

Arterial thrombosis (e.g. femoral artery).

Bleeding from sites of sheath insertion.

Malaise, mild hypotension and fever due to the release of tumour necrosis factor and other vasoactive compounds from necrotic tissue. This can last for weeks after the procedure.

Occasionally life threatening hypovolaemia with renal failure due to severe vasodilatation. This is now rare when octreotide is used, but patients must be well hydrated pre- and immediately post-embolization.

Rarely infarction of other intra-abdominal organs including the gallbladder.

Rarely infection introduced during procedure and rarely abscesses in the liver, which can develop late.

Rarely tumour lysis syndrome, which is why allopurinol has been added to protocol.

PREPARATION

1 week before procedure:

- Dual-phase contrast CT abdomen to establish baseline for size, location of metastases.

- Optional Doppler USS liver to establish portal vein patency (this is always established by Prof Jackson immediately before embolization).

- Take blood for FBC, U+Es, clotting, G+S.

- CXR, ECG.

- Echocardiogram if carcinoid and no previous echo.

Day before:

- May need to put in central venous catheter and urinary catheter (low threshold).

- Insert three large cannulae, if not using central venous catheter.

- Document foot pulses.

- No evidence of infection.

- Informed consent.

- Premed (discuss with radiologist).

- Discuss with anaesthetic SR on call regarding possible need for ITU bed.

- Start 1l 0.9% saline with 20 mmol KCl from midnight before procedure.

- Write up protocol medication:

PROTOCOL MEDICATION

Start on admission:

- Allopurinol 300 mg p.o. od for 10 days.

- Cyproheptadine 4 mg p.o. tds (histamine blocker – in carcinoids) for 72 hrs post procedure.

- Nicotinamide no longer used as it causes extreme flushing in carcinoids. It can be used in lower doses chronically to avoid Pellagra.

To start on morning of procedure and continue for 48 hrs:

- Octreotide: 1600 mcg in 48 ml 0.9% saline, i.v. at 6 ml/hr (i.e. 8 hrs). Write up 6 syringes.

- Trasylol (aprotinin): 50 ml neat (10,000 U/ml) i.v. at 5 ml/hr (i.e. 10 hrs). Write up 5 syringes.

One hour before procedure:

- Methylprednisolone 1g i.v.

- Premedication (discuss with Prof Jackson).

Antibiotic cover:

Pre-procedure

- Amoxycillin 1g i.v. (or Teicholplanin 400 mg 12 hourly if penicillin allergic).

- Metronidazole 500mg i.v.

- Gentamicin 120mg i.v.

Post-procedure

2 further doses of

- Amoxycillin 1g i.v. 8 hourly

- Metronidazole 500mg i.v. 8 hourly

Have available:

- Hydralazine i.v. for hypertension (alternatively nitroprusside, labetalol).

- Colloids for hypotension.

- Methylprednisolone.

POST-EMBOLIZATION

Usual post angiogram observations (i.e. foot temperature, peripheral pulses, Tº, BP and HR).

Careful attention to fluid balance is needed.

Daily biochemistry including GGT, CRP, and haematology for at least 3 days.

Monitor specific tests, e.g. urinary 5-HIAA in carcinoid syndrome or gut peptides, every other day.

Expect pyrexia and malaise for up to ten days but perform blood cultures daily until pyrexia subsides.

If abdominal symptoms persist, arrange appropriate investigations (erect and supine X-rays, U/S abdomen) and ask for a surgical opinion.

RESULTS OF TREATMENT

In approximately 60%-80% of patients who have symptoms from secreting hepatic secondaries there will be an improvement with embolization. Revascularisation will occur with a recurrence of symptoms after weeks, months or years. Embolization can be successfully repeated.

Hepatic embolization is not known to prolong life – this is purely a palliative procedure.

REFERENCE

Allison D.M., Br. J. Hosp. Med. 20, 707-715 (1978).

Adjani J.A. et al., Ann. Intern. Med. 108(3), 340-4 (1988).

VERSION HISTORY

SGG 11/89; revised BK 7/00 and SS 07/01

CHEMOTHERAPY FOR NEUROENDOCRINE TUMOURS

Coordinate with oncology: Prof Waxman’s team.

INDICATIONS

Patients with established neuroendocrine tumour, to reduce tumour bulk and improve symptoms

INVESTIGATIONS

(to monitor renal, hepatic and bone marrow function, and response to treatment)

· 24.hr urine for creatinine clearance: chemotherapy contraindicated if <60 ml/min.

· Urinalysis twice daily during treatment and abandon if persistent proteinuria.

· FBC and biochemical profile on alternate days.

· Gut hormone screen and urinary 5HIAA before and after treatment.

· CT scanning and ultrasound where appropriate.

TREATMENT PROTOCOL

Streptozotocin 500 mg/m² | on alternate days

5-Fluorouracil 400 mg/m² | for 10 days

Chemotherapy given during 2^nd litre saline, each drug diluted in 10ml normal saline and administered slowly (1ml/min) via a fast-flowing drip.

Administered with:

1. 0.9% saline i.v. – 3 litres over 12 hours

2. Lorazepam 2mg i.v. | after 1^st litre saline

3. Dexamethasone 4mg i.v. | and 30 mins before

4. Metoclopramide 1mg/kg i.v. over 15 minutes | treatment commences

RESULTS OF TREATMENT

3–4 courses of chemotherapy are given every 2–3 months.

Response of the tumour is assessed after a further 6 months

Partial response occurs in

25% carcinoid

20% gastrinoma

60% malignant insulinoma

80% VIPoma

REFERENCE

Oberg et al., Acta Oncol. 28, 425 (1989).

OVARY

SCREENING FOR OVULATION

INDICATION

To confirm ovulation in a woman WITH PERIODS presenting with infertility.

BACKGROUND

1. LH and FSH rise for approximately 48 hours ("surge") at the onset of the ovulatory phase of the menstrual cycle.

2. Progesterone production rises in the ovulatory phase to a maximum during the luteal phase.

3. Basal body temperature rises by >0.5ºC during the ovulatory phase peaking about 8 days after the LH surge.

PREPARATION

Confirm menstruation. Exclude other causes of infertility including hyperprolactinaemia, chromosomal problems, and thyroid dysfunction.

METHOD

1. Arrange for blood to be taken on days 18, 21 and 24 for progesterone. Should be undertaken for at least 2 cycles.

2. A more intensive screening regimen is undertaken in the IVF clinic, and referral is an alternative option.

3. Blood for progesterone is taken in red top Vacutainers and may be posted to the lab.

INTERPRETATION

Progesterone >30 nmol/l between days 18 and 24 indicates an adequate luteal phase (production of progesterone by granulosa cell).

Evidence of ovulation and adequate luteal phase should prompt further investigation of causes of infertility unrelated to ovulation or menstrual cycle (husband's sperm count, tube problems etc.). A postcoital test should be considered if there is no evidence for any of these.

If there is no evidence of ovulation: review screening tests for other systemic causes of infertility or consider clomiphene test.

REFERENCE

Sverdloff R.S. et al., Endo. Metab. Clin. N. Amer. 17, 301-332 (1988).

PROGESTERONE CHALLENGE

Medroxyprogesterone 10 mg po QD x 5 days to induce uterine bleeding

If patient has bleeding within one week of stopping progesterone, then she has both a sufficient amount of estrogen to stimulate endometrial growth and a normal outflow tract, but she is lacking in progesterone. Anovulation is the cause. These women are at risk for endometrial hyperplasia from unopposed estrogen. They should be treated with cyclic progesterone to induce withdrawal bleeding periodically (≥ 4 times per year), or alternatively OCPs can be prescribed if no pregnancy is desired. If pregnancy is desired, clomiphene can be used to induce ovulation.

If patient has no bleeding, she either has an outflow-tract defect or is estrogen-deficient from ovarian failure or dysfunction of the hypothalamic-pituitary axis. You can use a combination oral contraceptive pill for 21 days to induce menses; if no bleeding-- the patient likely has outflow tract obstruction-- although this diagnosis is usually easily made by history alone.

CLOMIPHENE TEST

INDICATION

Demonstration of the capacity for ovulation to be induced in a woman with infertility and anovulation, using clomiphene, a selective oestrogen receptor modulator. .

NB This should be performed by the Fertility Specialists as these patients need follicle tracking

CONTRAINDICATIONS

Pregnancy.

PREPARATION

Timing of cycle needs to be explained (first day of period = day 0).

Women without cycles have to start test at an arbitrary time.

SIDE EFFECTS

Rarely causes abdominal bloating. Small risk of multiple pregnancy.

Rarely, ovarian hyperstimulation with cardiovascular collapse, ascites and pleural effusions.

METHOD

1. Give clomiphene for 5 days at dose of 50 mg/day starting at day 5.

2. Blood is taken for baseline measurements on day 6 and at 2 day intervals between days 18 and 24, measuring LH, FSH, progesterone and oestradiol.

3. Keep a temperature chart.

4. If the test is unsuccessful over 2 cycles, repeat using higher doses of clomiphene (100 and 200 mg/day), cautiously

INTERPRETATION

A rise in LH and FSH occurs, probably as a consequence of an anti-oestrogen effect giving a rise in GnRH. This in turn leads to follicular maturation, oestrogen production, LH release, and ovulation.

Thus a positive result is a:

rise in LH (to >20 U/l). rise in FSH (to >10 U/l).

rise in progesterone to >30 nmol/l.

rise in temperature by >0.5ºC to help confirm ovulation.

SENSITIVITY AND SPECIFICITY

The sensitivity and specificity is poorly defined. The difficulties with this test are:

a variable response to a given dose

the mechanism of clomiphene action is not known

therefore no clear-cut guidelines for a negative result

The potential value is that a positive result confirms relatively minor hypothalamo-pituitary dysfunction causing anovulation that should resolve spontaneously or be easily treated.

REFERENCE

Sverdloff R.S. et al., Endo. Metab. Clin N. Amer. 17, 301-332 (1988).

HYPOGONADOTROPHIC HYPOGONADISM

Fertility possible, but may need subcutaneous gonadotrophins:

Referral to Fertility Services at Queen Charlotte’s Hospital (Mr Stuart Lavery) as follicular tracking essential.

POLYCYSTIC OVARIAN SYNDROME

DIAGNOSTIC CRITERIA

Exclude hyperprolactinemia, non-classical congenital adrenal hyperplasia, thyroid dysfunction, androgen-secreting tumours, and Cushing's syndrome first.

NIH–NICHD criteria

Both hyperandrogenism and chronic anovulation

Rotterdam criteria

Two of the following conditions: hyperandrogenism; chronic anovulation; polycystic ovaries

Androgen Excess Society criteria

Hyperandrogenism and ovarian dysfunction (including infrequent or irregular ovulation or anovulation) and/or polycystic ovaries

APPROACH TO PCOS TREATMENT

Crucially, the approach will depend on what the most pressing symptom is.

HYPERANDROGENAEMIA (HIRSUTISM, ALOPECIA, ACNE)

In a hirsute woman, an adrenal or ovarian androgen producing tumour must be excluded if testosterone > 5 nmol/l (unlikely anyway, so some authors ignore this and simply repeat testosterone).

The patient needs to know that the effects can take 6-12 months to take hold, and that no treatment will make all hair ‘go away’.

Oral contraceptive pill (includes Dianette, even though this is officially not an OCP): works by increasing SHBG, competition of progestin for 5alpha reductase and androgen receptor, decreasing adrenal androgen production. Particularly indicated if patient wishes to have contraception, or wishes to have regular withdrawal bleeds. Contraindicated particularly if BMI>35, past history of DVT/PE, history of breast cancer, uncontrolled hypertension or smoker. Avoid the OCPs with levonorgestrel (e.g. Microgynon, Logynon) as these have androgenic activity.

Antiandrogens (e.g. cyproterone acetate, spironolactone, flutamide, finasteride): can be potentially teratogenic, so usually used in conjunction with reliable contraception. The combination of Dianette + cyproterone acetate 50 mg on days 1-10 is useful: monitor LFTs.

Vaniqa: cream, applied to face (only licensed for facial hirsutism). Can take up to 4 months to show total effects. Often causes skin rash.

Skin laser therapy: best employed if have fair skin/dark hair. There are various types of laser available: needs to be matched to complexion. Not usually available on NHS. Has a suppressive activity on hair growth.

Electrolysis: not usually available on NHS.

Regaine: effective for androgenic alopecia but effects wear off if stopped. Available over the counter (2% solution). Not prescribable on NHS.

Metformin: in general not a very good treatment for hirsutism.

OLIGOMENORRHOEA

Rationale for treatment is to prevent endometrial hyperplasia and theoretical risk of endometrial cancer, although direct evidence of effectiveness is lacking.

Oral contraceptive pill: see above. Will assure regular withdrawal bleeds.

Metformin: only moderately effective at restoring cycles.

Intermittent progestagens: e.g. Duphaston 10 mg od for 10 days. Will induce withdrawal bleed. Usual practice is to prescribe this 3-4 times through the year. Ensure patient is NOT pregnant before prescribing.

SUBFERTILITY

Assess ovulation with luteal phase progesterone measurement if menstruating regularly. Do not forget to obtain a seminal analysis from partner! Suggested treatment options:

Metformin: moderately effective in restoring ovulatory cycles, but the live birth rate compared to clomiphene is poor. Not licensed for PCOS. It is usual practice to stop metformin as soon as pregnancy is confirmed. There is no evidence that metformin reduces miscarriage rates and the rates of gestational diabetes mellitus. Data from a large clinical trial of metformin in pregnancy is awaited.

Clomiphene citrate: e.g. 50-100 mg od. Appears to be better than metformin in obtaining conception and live births in head-to-head trials. Should be used in conjunction with fertility unit and with ultrasonic ovulation tracking.

REFERENCES

Dunaif et al. Nature Clinical Practice Endocrinology & Metabolism (2008) vol. 4 (5) pp. 272-83

Koulouri et al. Clin Endocrinol (Oxf) (2008) vol. 68 (5) pp. 800-5

Legro et al. N. Engl. J. Med. (2007) vol. 356 (6) pp. 551-66

Updated TT and NMM 9/08

TESTIS

Idiopathic gynaecomastia is best treated with liposuction by a Plastic surgeon (eg Mr Simon Eccles at Charing Cross)

FERTILITY INDUCTION IN HYPOGONADOTROPHIC HYPOGONADISM

Patients who are on regular testosterone replacement must have this discontinued. Where the cause of infertility is hypogonadotrophic hypogonadism replacement with LH and FSH is carried out.

Dosing regimen for hypogonadism to induce spermatogenesis

HCG (Pregnyl) 1500iu subcutaneously twice per week for 6 months. HCG has the action of pituitary LH.
Measure testosterone levels every 8 weeks. LH stimulates the Leydig cells to make testosterone. If levels exceed the upper limit of normal (30nmol/l), the dose of Pregnyl can be halved.
Carry out sperm count after 6 months of Pregnyl treatment.
If still azoospermic, add to above Menopur 1 vial subcutaneously twice a week. Menopur contains 75u LH and 75u FSH. The aim of this is for the FSH component to hopefully induce spermatogenesis. The LH component of Menopur is not an issue in sperm induction and therefore, no adjustment of the Pregnyl dose is necessary.
Continue to check testosterone levels every 8 weeks. The dose of both Pregnyl and Menopur can be halved if levels exceed 30nmol/l. Re-check sperm count after 3 and 6 months of combination treatment. Combination treatment can be continued for 18 months.
If successful induction of spermatogenesis occurs consider sperm freezing (see www.meeran.info for instructions on to do this via Hammersmith Andrology laboratory).
Preparations of high purity synthetic FSH are available, but these are needed for stimulation of follicles in females, where LH will of course cause problems. These high purity preparations are more expensive, and are not required in males, where LH is given anyway.

FSH should induce an increase in testicular volume to the normal 15 mls bilaterally, which can occur over the course of a year.

The hospital undertakes regular sperm counts and testosterone levels and should inform the GP of any change in dose required.

Updated 11/08 NMM and KM

NORMAL SEMEN ANALYSIS RESULTS

Parameter Reference value

Volume > 2.0ml

Viscosity Normal

pH 7.2-8.1

Sperm conc (million/ml) >20

Motility % Rapid progressive >25%

Total >50%

Sperm morphology (normal forms) *

Vitality (% live / dead) >50%

MAR IgG (direct sperm antibody) Neg

Nucleated / round cells millions / ml <1

Leucocytes per ul (cyturtest) <25-75

International reference values are presently under review due to the introduction of ‘strict criteria’ used in the definition of ‘Normal morphology’ & a lack of between laboratory consensus.

Post vasectomy 2 separate samples with ‘no sperm present’

OTHER MISCELLANEOUS CONDITIONS

SYSTEMIC MASTOCYTOSIS

METHOD

1. Collect a sample of urine shortly after an attack for urinary methyl histamine, which will be excreted in the following hour. A spot urine is adequate.

2. Also collect a clotted sample of blood for serum tryptase.

3. Collect a further sample of urine and blood 24h later to serve as a baseline for comparison.

- Thus two samples of serum and two samples of urine should be sent together for assay of urinary methyl histamine and serum tryptase to Chemical Pathology on a white miscellaneous form.

- Assays for urinary methyl histamine and serum tryptase are carried out by Dr John Watkins, Department of Immunology, Northern General Hospital, P.O. Box 894, Sheffield S5 7YT. Tel: 01742 434343 ext 5728 Fax: 01742 619893

INTERPRETATION

Normal methyl histamine: 5–20 ng/ml.

Typical patient with systemic mastocytosis: >100 ng/ml

Typical patient following beesting: >2000 ng/ml

Normal plasma tryptase <1

VERSION HISTORY

KM 7/94

ISCHAEMIC LACTATE TEST

INDICATIONS

Suspected metabolic muscle disease.

This protocol is from Professor Land at Queen’s Square.

Contact numbers: 020 7837 3611 / 020 7833 9391.

CONTRAINDICATIONS

None.

PREPARATION

Warn biochemistry 24 hrs prior to test that assays for pyruvate, ammonia and lactate will be required.

Tubes for pyruvate: Tubes prepared in the lab by the addition of 2mls perhexilene and refrigerated overnight. Add 1ml of blood to each tube accurately. Specimens for pyruvate must be handled carefully and placed on ice and taken to the lab immediately.

Tubes for lactate: Grey top fluoride oxalate bottles (samples stored on ice).

Tubes for ammonia: 9 paediatric lithium-heparin tubes (samples stored on ice). The 9th tube is a control, to measure the background ammonia levels in the samples.

METHODS

1. Fast from midnight.

2. The patient must spend the day relaxing, not doing any exercise.

3. 2 people needed to assist with sampling.

4. Insert i.v. cannula into large forearm vein with a three-way tap.

5. All specimens should be free flowing blood.

6. Take baseline bloods (-2 min) for lactate, pyruvate, ammonia, CK, phosphate and uric acid.

- At each time point discard 3mls of blood from the cannula, take 1ml for pyruvate in a 2ml syringe so that the volume is accurate, and 6mls in a 10ml syringe for the rest. Flush the cannula with normal saline and put the bottles on ice immediately.

7. Place sphygmomanometer on the cannulated arm and inflate the cuff above systolic pressure. The patient exercises the arm rhythmically by squeezing some rolled up paper towels or a ball. The hand must be fully extended between squeezes. Exercise the hand for 2 minutes.

8. Release the cuff, this is time = 0.

9. At time 0, 1, 2, 4, 6, 8 and 10 min take blood for lactate, pyruvate and ammonia as above.

INTERPRETATION

- Normally the lactate rises by 3–5 x baseline.

- The ammonia rises from 40 µmol/l to about 100 µmol/l.

- The normal lactate:pyruvate ratio is 10-20 which rises to 30-40 on exercise.

The lactate test is positive when the patient exercises and they can’t open their hand fully. The lactate level remains unchanged, as glycogenolysis is defective. The ammonia level rises dramatically to 300-400 µmol/l. The lactate to pyruvate ratio is 10-30 and does not change on exercise.

VERSION HISTORY

AP, LS 01/98

Surgical contacts

Mr Nigel Mendoza

Consultant neurosurgeon for all pituitary surgery.

For referrals: secretary tel no. 020 8868 1790 and fax no. 020 88406 7487

Mr Fausto Palazzo

Consultant Endocrine Surgeon. Patients for parathyroidectomy, adrenalectomy or resection of neuroendocrine tumours should be referred to Mr Fausto Palazzo, endocrine surgeon at Hammersmith Hospital. Patients with thyroid masses needing FNA can be referred to him via his PAL2 clinic at Hammersmith.

For referrals: secretary tel no. 020 8383 8542 and fax no. 0208 383 32037

Miss Veronica Ferguson and Miss Jane Olver

Consultant Opthalmologists to see patients with thyroid eye disease needing review.

For referrals: Miss Ferguson’s secretary: 020 88461499

Eye clinic: tel no. 020 8846 1955 and fax no. 020 8846 1959

Professsor Alun Davies

Consultant Vascular Surgeon at Charing Cross hospital for sympathectomies in patients with sweating in who an endocrine cause eg carcinoid, phaeochromocytoma, has been excluded. Clinic codes E30, AHD 1 AHD2.

For referrals: secretary tel no. 020 8846 7320 and fax no. 020 8846 7362

Mr Simon Eccles

Consultant Plastic Surgeon at Charing Cross hospital for surgical treatment of gynaecomastia.

For referrals: secretary tel no. 020 8846 1790 and fax no. 020 8868 1848

Infertility contacts

Mr Stuart Lavery

Consultant Gynaecologist and Director IVF Hammersmith (Queen Charlotte’s Hospital)

For referrals: Tel: 02083834152 Fax: 02087496973

REFERENCE RANGES

Compound [MW]	Conditions	Reference range	Sample
*STEROIDS & RELATED*
Oestradiol [272]	Early follicular	<300 pmol/l	A
	Luteal	250 – 1000 pmol/l	A
	Pre–ovulatory	400 – 1200 pmol/l	A
	Post–menopausal	<190 pmol/l	A
	Male	<190 pmol/l	A
Oestrone	Post menopausal	<260 pmol/l	A
Testosterone [288]	Female	<3.0 nmol/l	A
	Male	10 – 30 nmol/l	A
5-dihydrotestosterone	Female	<1.0 nmol/l	A
	Male	1.0 – 3.0 nmol/l	A
Androstenedione	Female	4 – 10.2 nmol/l	A
DHEAS	Female 20-40y Female 40 – 60y Female >60y	0.7 – 11.5 μmol/l 0.8 – 6.9 μmol/l 0.4 – 4.7 μmol/l	A
Sex Hormone Binding Globulin	Male	20–40 nmol/l	A
	Female	40–80 nmol/l	A
Progesterone	Follicular	0 - 5 nmol/l	A
	Luteal	20 - 100 nmol/l	A
17-OH progesterone		<10 nmol/l	A
Deoxycortisol	Basal	5 – 12.1 nmol/l	A
Cortisol [362]	0900h	200 – 700 nmol/l	A
	2400h	60 - 250 nmol/l	A
Not acid bottle unless cats also	24h urine free (plain bottle)	50 – 270 nmol/24hr	U1
*ANTERIOR PITUITARY*
ACTH [4500]	0900h	<30 ng/l	C
	2400h	<10 ng/l	C
β-hCG	non-pregnant	0 - 4 iU/l	A
LH [28000]	Follicular	2 – 10 U/l	A
	Luteal	4 – 14 U/l	A
	Mid–cycle	20 – 60 U/l	A
	Postmenopausal	>20	A
	Male	2 - 12 U/l	A
FSH [28–41,000]	Follicular	1.5 – 10 U/l	A
	Luteal	1.5 – 8 U/l	A
	Mid-cycle	7 – 20 U/l	A
	Postmenopausal	>20 U/l	A
	Male	1.7 – 8 U/l	A
Prolactin [21000]	Female	125 – 625 mIU/l	A
	Male	75 – 375 mIU/l	A
GH [21500]	During ITT	>6 µg/l	A
	During GTT	<0.6 µg/l	A
*THYROID*
TSH [27000]		0.3 – 4.2 mU/l	A
Free T4 [711]		9.0 – 26.0 pmol/l	A
Free T3		2.5 – 5.7 pmol/l	A
Thyroglobulin		<1 μg/l	A*
*CALCIUM METABOLISM*
Calcitonin		0 – 5.5 ng/l (female); 0 – 18.9 ng/l (male)	D
Intact PTH	Urgent to lab.	1.1 – 6.8 pmol/l	C
25-OH vitamin D		25 – 120 pmol/l	B
*PEPTIDE HORMONES*
Insulin [5807]	Fasting	3 – 17 mU/l	B
C-peptide	Fasting	~30 – 75 x insulin	B
IGF-1	< 5 y 6 - 10 y 11 – 16 y 17 – 20 y 21 – 60 y > 60 y	3 - 36 nmol/l 4 – 90 nmol/l 11 – 125 nmol/l 19 – 101 nmol/l 13 – 64 nmol/l 6 – 30 nmol/l	A
Somatostatin	Fasting	<150 pmol/l	E
GAWK	Fasting	<150 pmol/l	E
Proglucagon	Fasting	<50 pmol/l	E
Gastrin	Fasting	<40 pmol/l	E
VIP	Fasting	<30 pmol/l	E
Neurotensin	Fasting	<100 pmol/l	E
Pancreatic polypeptide	Fasting	<300 pmol/l	E
*OTHER ADRENAL HORMONES*
Renin	Erect	2.8 – 4.5 pmol/ml/h	F
	Supine	1.1 – 2.7 pmol/ml/h	F
Aldosterone	Supine	100 – 450 pmol/l	A
24 hr urine adrenaline		0.03 – 0.10 μmol/24 hrs	U2
24 hr urine noradrenaline		0.12 – 0.50 μmol/24 hrs	U2
24 hr urine dopamine		0.65 – 2.70 μmol/24hrs	U2
*CARCINOID SYNDROME*
24 hr urine 5-HIAA		15.0 – 40.0 μmol/24hrs	U3

Updated by JC 9/08.

BLOOD

A. 7 ml blood into a plain glass tube (red top Vacutainer) delivered to the lab the same day or kept in a refrigerator overnight

B. 7 ml blood in a plain glass tube (red top Vacutainer) delivered to the lab within 30 minutes

C. 4 ml blood in EDTA (purple top Vacutainer) delivered to the lab IMMEDIATELY to be spun, separated and frozen.

D. 7 ml blood in a lithium heparin tube (green top Vacutainer) brought to the lab IMMEDIATELY on ice to be separated and frozen.

E. 7 ml blood in a lithium heparin tube (green top Vacutainer) containing 200 μl Trasylol (10,000 KIU aprotinin/ml) brought to the lab immediately on ice.

F. As for D but NOT on ice.

*Samples analysed off site. Specimens dispatched once a week on Monday.

URINE (U)

Two main types of bottles are available for 24 hour urine collections.

1. No Preservative: ELUC (Na⁺, K⁺, urea, creatinine), creatinine clearance, total protein, uric acid, amylase, cortisol, urinary steroid profile.

2. 10% HCl: (hydrochloric acid): ELUC (Na⁺, K⁺, Urea, Creatinine), creatinine clearance, calcium, phosphate, magnesium, oxalate, catecholamines, VMA, 5HIAA, cortisol

3. 25% Acetic Acid: 5-HIAA is no longer used.

Since an acid bottle can be used for most tests, provided you are not measuring total protein, uric acid or amylase, an acid bottle should be requested.

URGENT SAMPLES AND LOCALISATION STUDIES

· Requests must be made in person to a Clinical Scientist (Dr Mandy Donaldson or Mrs S Fernandez) extension 34681.

· For localisation studies:

Give at least 1–2 days notice

Provide lab with patients name and type of study and starting time.

Keep lab informed if samples likely to arrive after 5 pm, or if procedure cancelled.

If the samples are to be delivered within an hour of collection, it is not necessary to collect samples for PTH and insulin on ice.

ACTH and gut peptides must be collected on ice.

REFERENCE RANGES FOR THYROID FUNCTION IN PREGNANCY

Up to 12 weeks gestation

fT4 9.9-15.2 pmol/l TSH 0.2-3.6 mU/l

12-24 weeks gestation

fT4 9-14.3 pmol/l TSH 0.6-2.8 mU/l

24-36 weeks gestation

fT4 8.1-13.4pmol/l TSH 0.4-3.9 mU/l

Courtesy of Queen Charlotte’s Hospital, NMM 11/08

USEFUL NAMES AND ADDRESSES

Diabetes UK 10 Queen Anne Street
London W1M OBD
Tel: 020 7343 1531

Society for Endocrinology 17/18 The Courtyard
Woodlands
Bradley Stoke
Bristol BS32 4NQ
Tel: 01454 201612

The British Thyroid Foundation Mrs J Hickey
PO Box HP22
Leeds LS6 3RT

National Osteoporosis Society Dr J A Dixon
PO Box 10
Radstock
Bath BA3 3YB
Tel: 01761 471771

The Pituitary Foundation 17/18 The Courtyard
Woodlands
Bradley Stoke
Bristol BS32 4NQ
Tel: 01454 201612

National Society for the 1 Church Road

Relief of Paget’s Disease Eccles
Manchester M30 0DL
Tel: 0161 707 9225

CAH Support Group The Child Growth Foundation
2 Mayfield Avenue, Chiswick
London W4 1PW
Tel: 020 8995 0257

MEDIC alert foundation. 1 Bridge Wharf, 156 Caledonian Road,

London N1 9UU

Tel: 020 7833 3034