Alcoholic pseudo-Cushing’s syndrome: mimics both the biochemistry and clinical features of Cushing’s syndrome
Fatima Alkaabi, Amir H Sam, Karim Meeran, Endocrine Unit, Charing Cross Hospital.
Diagnosis of Cushing’s syndrome can be challenging. Many of the features of Cushing’s syndrome such as weight gain, diabetes mellitus and hypertension are common in the general population. Therefore, biochemical investigations for suspected Cushing’s syndrome should only be carried out when there is a high pre-test probability with presence of discriminatory features such as myopathy, diabetes or hypertension in young patients.
We report the case of a 37-year-old woman who presented with lower limb weakness and inability to stand from a seated position. She also complained of paraesthesia in her hands and feet. She reported weight gain and amenorrhea over the last six months. She had a history of excess alcohol intake. Her BP was 181/102 mmHg and weight 115 kg. She had round facies, plethoric complexion and interscapular fat pad. There was no evidence of abdominal striae or bruising. Neurological examination revealed proximal muscle weakness in both upper and lower limbs, normal pin prick and vibration sensation and an ataxic gait.
Her initial investigations showed elevated fasting blood sugar (9.4 mmol/L) and HA1c (63 mmol/mol), low serum potassium (2.8 mmol/L), normal vitamin B12 (418 ng/L) and folate (3.2 ng/ml) levels. She had raised GGT (1068 IU/L), low vitamin D levels (< 10 nmol/L). She was treated with potassium, vitamin D and thiamine replacement. She was also started on metformin, doxazosin, indapamide and pregabalin. Her serum cortisol level post overnight dexamethasone suppression test was 75 nmol/L. Her late night salivary cortisol was 6.2 nmol/L (reference range <2.6). Her 24 urine free cortisol was normal. She was asked to stop drinking alcohol. Her repeat investigations after one month of abstinence showed normal serum potassium, low dose dexamethasone suppression test (<20 nmol/L) and late night salivary cortisol (0.9nmol/L). Her aldosterone renin ratio measured off interfering medications was 342. Nerve conduction studies showed a sensorimotor polyneuropathy. Excess alcohol intake can present with the ‘discriminatory features’ of Cushing’s syndrome. Investigations for Cushing’s syndrome must be repeated after a period of abstinence to rule out false positive results.