Suspected NMS
Patient on dopamine antagonist with concerning symptoms
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PsychiatryEmergency
Neuroleptic Malignant Syndrome (NMS) Management
Neuroleptic Malignant Syndrome (NMS) Management: Suspected NMS → Recognize Clinical Features → Identify Offending Agent → ⚠️ STOP Offending Agent Immedi...
Pathway Overview
15 steps
Algorithm Steps
15 total
01Start 02Action Recognize Clinical Features
Classic tetrad (may be incomplete)
- Hyperthermia (>38°C, often >40°C)
- Muscular rigidity ('lead-pipe')
- Altered mental status (confusion → coma)
- Autonomic instability (tachycardia, labile BP, diaphoresis)
03Action Identify Offending Agent
Recent exposure to dopamine-blocking agent
- Typical antipsychotics (haloperidol, fluphenazine)
- Atypical antipsychotics (any)
- Antiemetics (metoclopramide, prochlorperazine)
- Dopamine withdrawal (stopping levodopa, amantadine)
- Onset: hours to weeks after starting/increasing
04Warning ⚠️ STOP Offending Agent Immediately
Discontinue ALL dopamine antagonists
- Stop antipsychotic immediately
- Stop antiemetics (metoclopramide, etc.)
- If Parkinson's patient: restart dopamine agonist
05Action Order Diagnostic Workup
Labs and imaging to confirm and monitor
- CK (often >1000 U/L, may exceed 100,000)
- CBC with differential (leukocytosis common)
- BMP (renal function for rhabdomyolysis)
- LFTs
- Lactate
- Myoglobin (urine)
- Iron studies (low serum iron in NMS)
06Decision Assess Severity
Determine level of care needed
07Action Mild NMS
Low-grade fever, mild rigidity, stable vitals
- Stop offending agent
- Supportive care
- IV fluids
- Benzodiazepines PRN for rigidity
- Close monitoring - can progress
08Decision Response to Treatment?
Reassess in 24-48 hours
09Outcome Improving
Continue supportive care, wean medications
- Continue treatment 10-14 days after resolution
- Monitor for complications
- Consider psychiatry consult for alternative medications
10Warning ⚠️ Monitor for Complications
Life-threatening complications
- Rhabdomyolysis → acute kidney injury
- Aspiration pneumonia
- Respiratory failure
- DIC
- Cardiac arrhythmias
- Mortality: 5-20%
11Action Future Antipsychotic Use
Rechallenge considerations
- Wait at least 2 weeks after NMS resolution
- Use different antipsychotic (lower potency)
- Start at low dose, titrate slowly
- Consider clozapine (lowest NMS risk)
- Close monitoring during rechallenge
12Warning Refractory NMS
Consider electroconvulsive therapy (ECT)
- ECT effective in refractory cases
- Response rate ~73% in case series
- Also treats underlying psychiatric condition
- Bilateral electrode placement preferred
- Path rejoins step 10Shared downstream outcome
13Warning Moderate-Severe NMS
High fever, severe rigidity, autonomic instability
- ICU admission required
- Aggressive IV fluids (rhabdomyolysis)
- Active cooling measures
- Continuous cardiac monitoring
14Action Aggressive Supportive Care
Core management for all moderate-severe cases
- IV fluids: Aggressive hydration (target UOP >200mL/hr)
- Cooling: Ice packs, cooling blankets, cold IV fluids
- VTE prophylaxis
- Respiratory support (may need intubation)
- Benzodiazepines: Lorazepam 1-2mg IV for rigidity/agitation
15Action Specific Pharmacotherapy
Consider for moderate-severe cases
- DANTROLENE: 1-2.5mg/kg IV, repeat q5-10min (max 10mg/kg/day)
- - For severe rigidity and hyperthermia
- - Reduces muscle contraction
- BROMOCRIPTINE: 2.5-5mg PO/NG TID (max 45mg/day)
- - Dopamine agonist
- - Avoid if unable to protect airway
- AMANTADINE: 100mg PO/NG BID-TID alternative
- Path rejoins step 08Shared downstream outcome
Guideline Source
Neuroleptic Malignant Syndrome - NEJM Review 2024
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- NMS is a clinical diagnosis - no pathognomonic test
- Must differentiate from serotonin syndrome, malignant hyperthermia, catatonia
- Severity varies widely - mild cases may be missed
- Drug-drug interactions may contribute
- Rechallenge with antipsychotics requires careful consideration
Applicable Regions
USEUGlobal
Version 1Next review: 2027-01-11
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Frequently Asked Questions
What is the Neuroleptic Malignant Syndrome (NMS) Management?
The Neuroleptic Malignant Syndrome (NMS) Management is a emergency clinical algorithm for Psychiatry. It provides a structured decision tree to guide clinical decision-making, based on Neuroleptic Malignant Syndrome - NEJM Review 2024.
What guideline is the Neuroleptic Malignant Syndrome (NMS) Management based on?
This algorithm is based on Neuroleptic Malignant Syndrome - NEJM Review 2024 (DOI: 10.1056/NEJMra2404606).
What are the limitations of the Neuroleptic Malignant Syndrome (NMS) Management?
Known limitations include: NMS is a clinical diagnosis - no pathognomonic test; Must differentiate from serotonin syndrome, malignant hyperthermia, catatonia; Severity varies widely - mild cases may be missed; Drug-drug interactions may contribute; Rechallenge with antipsychotics requires careful consideration. Individual patient factors may require deviation from these recommendations.
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