A rare iatrogenic association of syndrome of inappropriate secretion of antidiuretic hormone, neuroleptic malignant syndrome and rhabdomyolysis.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is considered the prevalent cause of hyponatremia in hospitalized patients. Neuroleptic malign syndrome (NMS) is an idiosyncratic drug reaction showing fever, dysautonomia and rigidity with increased levels of Creatinine-phosphokinase (CPK) dependent on leakage of muscle contents into the circulation and defined as rhabdomyolysis. Although different diagnostic criteria for NMS have been established, it should be recognized that atypical presentations occur, particularly during treatment with atypical antipsychotics. We here present a case report of a psychiatric patient affected by a SIADH complicated with NMS/rhabdomyolysis, induced by second-generation (atypical) antipsychotic drugs in combination with carbamazepine and promazine.