Neuroleptic Malignant Syndrome (NMS) — Pathway

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

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Full pathway

1. [Decision] Does it meet NMS?
   Dopamine antagonist + the tetrad? (NMS: onset over days to weeks after a dopamine antagonist (antipsychotic, metoclopramide) or abrupt withdrawal of a dopaminergic drug. Tetrad: hyperthermia, lead-pipe generalized rigidity (hyporeflexia, not clonus), altered mentation, autonomic instability; markedly raised CK, leukocytosis, low serum iron. Differentiate from serotonin syndrome (the latter has clonus/hyperreflexia, rapid onset, GI symptoms).)
   • Meets NMS → Confirmed → stop drug + support
   • Not met / consider serotonin syndrome, etc. → Not met
2. [End] Not met
   Differentiate serotonin syndrome (clonus/hyperreflexia, serotonergic drug), malignant hyperthermia (inhalational anesthetic/succinylcholine), thyroid storm, encephalitis, heat stroke, etc., and manage along the appropriate pathway.
3. [End] Confirmed → stop drug + support
   1) Immediately stop the offending dopamine antagonist (or, if caused by abrupt dopaminergic withdrawal, restart it). 2) Support: aggressive cooling, fluids (prevent AKI from rhabdomyolysis), ICU, monitoring, correct electrolytes. 3) Benzodiazepines for agitation (may suffice alone in mild cases). 4) Severe: dantrolene (reduces rigidity/heat production), bromocriptine or amantadine (dopamine agonists). 5) Refractory: electroconvulsive therapy. Monitor CK and renal function.

Source guidelines & references

• NMS diagnosis and management (EMCrit; international consensus diagnostic criteria)

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

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