Cerebral salt wasting induced hyponatraemia presenting as catatonia.

Cerebral salt wasting (CSW) is an important cause of hyponatraemia in the background of a central nervous system disease. It causes hypovolaemic hyponatraemia and is associated with polyuria and high urine sodium levels. It is important to distinguish it from the more common syndrome of inappropriate antidiuretic hormone and this is primarily based on the volume status. Although CSW has been known to present with confusion, stupor, abnormal behaviour and seizures, its association with catatonia is yet to be reported. We report a case in which the patient developed CSW and hyponatraemia as a sequela of tuberculous meningitis and presented with catatonia. Prompt correction of hyponatraemia resulted in complete reversal of catatonia. This highlights the importance of evaluating all patients with catatonia for electrolyte abnormalities, especially hyponatraemia as its correction leads to excellent outcomes.