Neuroleptic malignant syndrome provoked by water intoxication.

Neuroleptic malignant syndrome is an uncommon but potentially life-threatening complication that can occur in association with neuroleptic therapy. We report a 35-year-old male patient with schizophrenia who developed neuroleptic malignant syndrome following psychogenic polydipsia. The patient was in a deep coma on admission and his serum sodium concentration was decreased to 113mEq/l due to water intoxication. Although hyponatremia was spontaneously corrected by 9, 300ml of diuresis during the following eight hours, he developed muscular rigidity and hyperthermia with a marked elevation of serum creatine phosphokinase (42, 524IU/l). His condition was diagnosed as neuroleptic malignant syndrome and successfully treated by combination therapy with bromocriptine and intravenous dantrolene in addition to strict management of body water balance. It was assumed that the rapid increase in free water volume had provoked neuroleptic malignant syndrome by changing the concentrations of neuroleptic drugs in brain tissue and by increasing the osmolality gap across the muscular cell membranes in this patient.