Diagnosis and treatment of neuroleptic malignant syndrome

A patient who developed neuroleptic malignant syndrome (NMS) from the use of several neuroleptic agents and the therapeutic interventions used to reverse the syndrome are described, and the clinical presentation and treatment of NMS are reviewed. Fever, leukocytosis, seizures, delirium, and elevated serum creatine phosphokinase levels developed in a 17-year-old girl who was receiving perphenazine and haloperidol. The patient was admitted to a hospital for treatment of atypical psychosis and received haloperidol and, later, thioridazine. Autonomic disturbances, altered consciousness, and muscular rigidity developed. Thioridazine was discontinued in favor of perphenazine because of anticholinergic adverse effects. Symptoms persisted despite treatment with benztropine and diphenhydramine. After the diagnosis of NMS was made, all neuroleptics were discontinued, and the patient began therapy with dantrolene sodium and bromocriptine. Dramatic improvement in the patient's condition followed. NMS has four characteristic signs: hyperthermia, muscular rigidity, altered consciousness, and autonomic dysfunction. Mechanisms believed to cause NMS include alteration of central neuoregulatory mechanisms and neuroleptic-induced imbalance between central dopaminergic and gamma-aminobutyric acid neurotransmitter systems. Bromocriptine, amantadine, dantrolene sodium, and electroconvulsive therapy have been used effectively in the treatment of NMS. NMS is a rare but potentially fatal adverse drug reaction that occurs in situations that make diagnosis difficult. Dramatic, favorable responses can be achieved with early diagnosis and appropriate treatment.