Neuroleptic malignant syndrome (NMS), caused by antipsychotic therapy, shows itself with mental status alteration, high fever, autonomic dysfunction, and muscle rigidity. It is a rare idiosyncratic reaction with mortality risk. The etiology is still unknown. NMS-related mortality and morbidity can be decreased by cessation of the used drug and aggressive treatment. Olanzapine is a thienobenzodiazepine, a member of atypical antipsychotic drugs; its structure and effects on neurotransmitters resemble clozapine. Here we report a case of bipolar disorder receiving olanzapine therapy for 10 years, who developed NMS without rigidity. We emphasized the importance of early hydration and hemodiafiltration therapy.
Keywords: Neuroleptic malignant syndrome, olanzapine, rigidity, hemodiafiltration