Haloperidol Induced Neuroleptic Malignant Syndrome

An episode of haloperidol induced neuroleptic malignant syndrome in a 58 year-old chronic schizophrenic is described. The patient was admitted for control of agitation and hallucinations and was treated with haloperidol. Characteristic signs and symptoms included temperature elevation to 107°F (rectal), increased muscle tone, tachycardia, acute agitation, psychotic behavior followed by lethargy. Laboratory abnormalities included elevated liver function tests and serum creatine phosphokinase levels. The syndrome was not diagnosed until the fourth hospital day at which time haloperidol was discontinued, and he improved over the next eight days. Haloperidol was readministered on the twelfth hospital day. He immediately spiked a temperature to 103°F and haloperidol was stopped. It is interesting that the syndrome does not always recur with rechallenge. This case discusses an important but little known drug-induced disorder. Greater awareness of rare events may help prevent diagnostic delays that could result in prolonged patient discomfort and morbidity.