Neuroleptic malignant syndrome in a patient treated with lithium carbonate and haloperidol

A 39-year-old female with a 20-year history of bipolar disorder was admitted due to a recurrence of a manic episode with psychotic symptoms. She was treated with standard doses of lithium carbonate and clozapine. Three days after admission, she showed aggressive behavior and refused to take her medications so her oral clozapine was switched to intramuscular haloperidol. Three days later she developed a high temperature and exhibited symptoms of neuroleptic malignant syndrome (NMS) including excessive sweating, cramps and tremors in limb muscles, muscle rigidity, and impaired consciousness. The haloperidol and lithium were stopped immediately, symptomatic treatment was provided, and she was administered the dopamine agonist bromocriptine. The NMS symptoms resolved within three days but she continued to have severe psychotic symptoms. She was subsequently re-challenged with valproate and olanzapine but the NMS did not re-occur. After one month of this treatment she recovered and was discharged. Several case histories similar to this one suggest - but do not prove - that individuals concurrently receiving lithium and antipsychotic medications may be at higher risk of developing NMS than those receiving monotherapy with antipsychotic medication.