catatonia; cerebral salt wasting; hyponatraemia

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.