## Clinical Presentation & Diagnosis The patient presents with **neuroleptic malignant syndrome (NMS)** — a life-threatening idiosyncratic reaction to antipsychotics characterized by the classic tetrad: 1. **Muscle rigidity** (lead-pipe) 2. **Fever** (often > 39°C) 3. **Altered mental status** (confusion, delirium) 4. **Autonomic instability** (tachycardia, hypertension, diaphoresis) Elevated CK (1850 U/L) reflects rhabdomyolysis secondary to sustained muscle contraction. **Key Point:** NMS is a medical emergency with mortality of 5–20% if untreated. It can occur at any time during antipsychotic therapy, even with typical doses. Early recognition and aggressive management are critical. ## Diagnostic Criteria for NMS | Feature | Presence | |---------|----------| | Exposure to antipsychotic | Yes (olanzapine 6 months) | | Fever (≥38.5°C) | Yes (39.8°C) | | Muscle rigidity | Yes (severe) | | Altered mental status | Yes | | Elevated CK (>1000 U/L) | Yes (1850 U/L) | | Autonomic instability | Yes (HR 118, BP 160/95) | ## Management Algorithm for NMS ```mermaid flowchart TD A[Suspected NMS: fever + rigidity + altered MS + autonomy]:::urgent --> B[Immediate actions]:::action B --> C[Discontinue antipsychotic]:::action B --> D[Admit to ICU]:::action B --> E[Aggressive supportive care]:::action E --> F[IV fluids, cooling measures]:::action E --> G[Treat rhabdomyolysis]:::action G --> H[Monitor urine output, CK, renal function]:::action I[Pharmacologic treatment]:::action --> J{Severe/Refractory?}:::decision J -->|Yes| K[Dantrolene 1 mg/kg IV stat]:::action J -->|Yes| L[Bromocriptine 2.5-5 mg TID]:::action J -->|No| M[Supportive care alone]:::action K --> N[Repeat dantrolene q5min, max 10 mg/kg/day]:::action ``` ## Immediate Management Steps (In Order) 1. **Discontinue antipsychotic immediately** — this is non-negotiable and the single most important intervention 2. **ICU admission** for continuous monitoring 3. **Aggressive IV hydration** (0.5–1 L/hr) to maintain urine output > 200 mL/hr and prevent acute kidney injury from myoglobinuria 4. **Cooling measures** (ice packs, cooling blankets) to reduce fever 5. **Dantrolene 1 mg/kg IV stat** — a skeletal muscle relaxant that inhibits calcium release from the sarcoplasmic reticulum, reducing muscle contraction and heat production 6. **Bromocriptine 2.5–5 mg TID** (if dantrolene unavailable) — dopamine agonist to restore dopaminergic tone 7. **Monitor CK, electrolytes, renal function, urine myoglobin** every 4–6 hours **High-Yield:** Dantrolene is the definitive pharmacologic treatment for NMS. It must be given **immediately** in severe cases (high fever, very elevated CK, severe rigidity, altered consciousness). ## Why NOT Continue Olanzapine? **Warning:** Continuing the antipsychotic in NMS is **fatal**. The drug is the cause; it must be stopped immediately. Continuing it while adding dantrolene delays the critical first step and risks death from progressive rhabdomyolysis, DIC, and acute renal failure. ## Why NOT Dose Reduction? Dose reduction is insufficient. The entire antipsychotic must be discontinued. Reducing the dose prolongs exposure and worsens outcomes. ## Why NOT Benzodiazepine Monotherapy? Benzodiazepines provide sedation and may reduce agitation but do not address the underlying pathology (dopamine blockade, muscle hypermetabolism, rhabdomyolysis). They are adjunctive only. Dantrolene is the specific treatment. ## Recovery & Rechallenge - Most patients recover within 24–72 hours of antipsychotic discontinuation - CK normalizes over 7–10 days - **Rechallenge:** If antipsychotic is necessary, use a different agent (preferably clozapine, which has the lowest NMS risk) after 2–4 weeks, with informed consent and close monitoring [cite:Stahl's Essential Psychopharmacology 6e Ch 8; Kaplan & Sadock 21e Ch 29; Harrison 21e Ch 385]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.