Neuroleptic Malignant Syndrome
Pronunciation: nyur-oh-LEP-tik ma-LIG-nant SIN-drome
Also written as: NMS — Neuroleptic Malignant Syndrome
A rare but life-threatening adverse reaction to antipsychotic medications characterised by hyperthermia, muscle rigidity, autonomic instability, and altered consciousness.
Full Definition
Neuroleptic malignant syndrome (NMS) is a medical emergency triggered most commonly by dopamine-antagonist antipsychotics, though it can also arise from abrupt discontinuation of dopaminergic agents. The classic tetrad includes high fever, severe muscle rigidity (often described as 'lead-pipe rigidity'), autonomic dysfunction, and altered mental status. Laboratory findings typically show elevated creatine kinase (CK). In emergency psychiatry documents, editors must carefully distinguish NMS from serotonin syndrome, which has overlapping features but different causation, treatment, and clinical trajectory. The two are among the most commonly confounded drug-reaction syndromes in editorial and clinical contexts.
Usage
Usage note: NMS and serotonin syndrome are frequently confused in manuscripts. Key differentiators for editors: NMS features bradyreflexia and lead-pipe rigidity; serotonin syndrome features hyperreflexia and clonus.
In Context
- "The case report described a delayed diagnosis of neuroleptic malignant syndrome in a patient who had been given haloperidol for acute agitation twelve hours prior." — Case report / journal article
- "Authors often conflate NMS and serotonin syndrome; editors should verify that the described symptom onset, rigidity pattern, and causative agent are consistent with the diagnosis named." — Editorial review note