Salt-Wasting and Hyponatremia in Neuroleptic Malignant Syndrome

With their report¹ of cerebral salt-wasting syndrome in a patient with neuroleptic malignant syndrome (NMS), Dr Lenhard and colleagues have taken a potentially important step toward explicating the pathophysiology of NMS. Previous work² suggested that salt-wasting caused by profound diaphoresis might explain electrolyte and fluid imbalances in NMS and the frequent co-occurrence of severe diaphoresis, hyponatremia, and polydipsia in that disorder. However, Lenhard et al propose that elevated levels of adrenomedullary brain natriuretic peptide (BNP) caused the severe hyponatremia observed in their patient. This alternative mechanism is intriguing because it represents a more direct consequence of the dysregulated hyperautonomic state that is central to NMS.