Atypical neuroleptic malignant syndrome caused by olanzapine.

OBJECTIVE: Neuroleptic malignant syndrome (NMS) is a rare syndrome with four main symptoms: rigidity, hyperthermia, altered mental status and autonomic instability. We report a patient with an atypical manifestation of NMS.

METHOD: A single case was reported.

RESULTS: A patient with pneumonia developed delirium and was treated with olanzapine and developed a NMS with fluctuating hyperthermia and autonomic instability during a month. Only slight rigidity was present. Creatine kinase was not elevated. The patient was severely agitated and manic. After discontinuation of olanzapine the patient showed no psychopathology or hyperthermia.

CONCLUSION: NMS should be considered when patients treated with antipsychotics develop one or more symptoms of NMS.