To describe a case of relapsing neuroleptic malignant syndrome (NMS) with prolonged course over several weeks eventually leading to a good outcome.

NMS is a self-limited disorder associated with the use of antidopaminergic agents. Discontinuation of the offending drugs typically leads to recovery within 1-2 weeks with supportive care.  A secondary relapse is not known to occur. 

A 35 year old man with a history of substance abuse was admitted after an unwitnessed assault.  Injuries included multiple facial fractures but no radiographic intracranial injury.  For treatment of agitation, he received multiple doses of intravenous haloperidol and risperidone.  No depot preparations were administered.  On day 7, the patient was febrile with acute encephalopathy, diffuse rigidity, dysautonomia and hyperreflexia.  Laboratory studies were notable for leukocytosis of 34,000 and creatine kinase of 354.  Infectious workup, brain MRI , lumbar puncture, and EEG monitoring were all unrevealing.  NMS was diagnosed based on clinical criteria and all antipsychotics were discontinued. The patient was treated with bromocriptine and dantrolene, with marked improvement in mental status and muscle tone.  Dantrolene wean was started after 10 days of treatment, and was discontinued after 17 days; bromocriptine was weaned more slowly.  The patient subsequently had a relapse of NMS with worsening of all previous symptoms. He had not received any antidopaminergic drugs prior to the relapse. Dantrolene and bromocriptine were reinitiated; again with good clinical response and improvement in mental status.  Both drugs were then tapered very slowly over the next month, and patient was discharged home on day 71.  At 3 months follow-up, he had returned to his normal baseline.

Relapse of NMS with recurrence of symptoms more than 2 weeks after discontinuation of antidopaminergic drugs is not a known phenomenon. When it does occur, full recovery is still possible with prompt recognition and a prolonged treatment course.