Atypical neuroleptic malignant syndrome - A case report

Neuroleptic malignant syndrome (NMS) is a potentially fatal adverse effect of antipsychotics. Atypical presentation of NMS with drugs which are not potential D2 blockers raises question for an alternative hypothesis for NMS. A 30 year old male presented with irritability, assaultive behavior, persecutory delusion and auditory hallucination for three days. Past history of 3 similar episodes. 1st episode preceded by fever and associated with cerebral edema. Subsequent episodes not preceded by fever and patient was treated with Risperidone and Olanzapine. After admission patient was started on Risperidone along with THP when he had fever, tremors, altered sensorium and rigidity at 3 mg dose. After stopping Risperidone fever and rigidity improved with worsening of psychotic symptoms. Following this Olanzapine was started and very gradually uptitrated to 7.5 mg when patient had recurrence of fever and disorientation without tremors and minimal rigidity. Both the instances blood investigations including CPK levels were normal except for thrombocytopenia and leucopenia. Provisional impression of NMS was made in both instances. After stopping Olanzapine fever subsided with improvement of blood counts. Following this patient had catatonic symptoms for which patient received 9 sessions of Electroconvulsive therapy (ECT). In atypical presentations of NMS, hyperthermia and muscle rigidity may be absent, posing diagnostic dilemma. So there is a need for broadening the diagnostic criteria and NMS must be considered with a high index of suspicion.