Neuroleptic Malignant Syndrome: Emergency Management

Neuroleptic malignant syndrome (NMS) is a rare but life-threatening idiosyncratic reaction most commonly associated with first-generation antipsychotics, atypical antipsychotics and antiemetics that block dopamine D2 receptors. It can also occur with abrupt withdrawal of dopaminergic agents in Parkinson disease.

Clinical features include hyperthermia (often >40°C), generalized lead-pipe muscle rigidity, autonomic instability with labile blood pressure and tachycardia, altered mental status and elevated creatine kinase reflecting rhabdomyolysis. Complications include acute kidney injury, respiratory failure, disseminated intravascular coagulation and arrhythmias.

Differential diagnosis includes serotonin syndrome, malignant hyperthermia, anticholinergic toxicity and central nervous system infection. Management consists of immediate withdrawal of the offending agent, aggressive cooling, IV fluids, benzodiazepines, dantrolene or bromocriptine in severe cases and ICU support.