What is neuroleptic malignant syndrome?

Neuroleptic malignant syndrome, or NMS, is a rare but life-threatening reaction to antipsychotic medications characterized by four cardinal features: high fever often exceeding 40 degrees Celsius, severe muscle rigidity described as "lead pipe," autonomic instability with tachycardia and blood pressure fluctuations, and altered mental status. Laboratory findings include markedly elevated creatine kinase from muscle breakdown. NMS can occur with any dopamine-blocking medication, though typical antipsychotics carry the highest risk.