Acute hyponatremia and neuroleptic malignant syndrome in Parkinson's disease.

1. The neuroleptic malignant syndrome (NMS) may occur, occasionally, in Parkinson's disease (PD) after withdrawal of antiparkinsonian drugs. However, the circumstances in which the NMS occurs and the pathophysiologic mechanisms remain uncertain. 2. The authors studied a woman with PD, who developed hyperthermia, increased muscular tone, tremor, signs of autonomic dysfunction and stupor as symptoms of acute hyponatremia due to gastrointestinal loss of sodium in excess of water. 3. The correction of hyponatremia led to a complete recovery after about 6 hours. During this period the antiparkinsonian therapy was not modified. 4. An acute imbalance of sodium in the central nervous system may play a role in the pathophysiology of NMS.