Cerebral Salt Wasting Syndrome after Subarachnoid Haemorrhage: a case report
TB Smith, RW Caroll, K Meeran and K Wynne – Imperial Healthcare NHS Trust.
A 72 year old women was admitted with an extensive posterior fossa intracranial haemorrhage one day after the unsuccessful placement of a right coronary stent for stable angina. On day 14 of her admission she developed hyponatraemia (128 mmol/L) and polyuria (6250ml / 24hrs) with a consequent hypovolaemia and a negative 24 hour fluid balance of 3070mls. Plasma and urine biochemical investigation revealed a hypo-osmotic hyponatraemia with an inappropriate natriuresis (urine sodium 178 mmol/L) equivalent to a 1113 mmol loss of sodium per day. Cortisol deficiency was excluded and a diagnosis of cerebral salt wasting was made.
Fluid resuscitation with 0.9% saline resulted in clinical euvolaemia. The rate of fluid administration was set so that hourly fluid input was equal to hourly urine output. On day 18 the fluid replacement was gradually withdrawn and over the following week the patient’s urine output and serum sodium returned to within the reference range. The patient was discharged on day 26.
Cerebral Salt Wasting Syndrome is a recognised cause of hyponatraemia in neurosurgical patients. Its diagnosis relies upon the renal loss of sodium during an intracranial disorder leading to hyponatraemia and a decrease in extracellular volume1. The reduction in extracellular volume being a key differential from a diagnosis of syndrome of inappropriate antidiuretic hormone secretion. However the on going difficulty using these criteria to distinguish between the two makes Cerebral Salt Wasting Syndrome a controversial diagnosis2.
1. Cerdŕ-Esteve M, Cuadrado-Godia E, Chillaron JJ, Pont-Sunyer C, Cucurella G, Fernández M, Goday A, Cano-Pérez JF, Rodríguez-Campello A, Roquer J (2008) Cerebral salt wasting syndrome: Review. European Journal of Internal Medicine 19, 249–254
2. Sterns, RH & Silver, SM. (2008). Cerebral Salt Wasting Versus SIADH: What Difference? Journal of the American Society of Nephrology, 19, 194-196.