Key Points
- Stabilize ABCs; treat life‑threatening derangements immediately.
- Confirm diagnosis early with highest‑yield imaging/labs.
- Initiate guideline‑based therapy and escalate by response.
- Plan disposition and follow‑up explicitly.
Clinical Synopsis & Reasoning
Myasthenic crisis is impending/established ventilatory failure due to MG. Secure airway early; use short‑acting neuromuscular blockers if needed and avoid agents that worsen neuromuscular transmission. Choose IVIG 0.4 g/kg/day for 5 days or plasma exchange (5–6 exchanges), manage triggers, and titrate chronic immunotherapies. Extubation is guided by NIF, vital capacity, and clinical recovery.
Treatment Strategy & Disposition
Myasthenic crisis is impending/established ventilatory failure due to MG. Secure airway early; use short‑acting neuromuscular blockers if needed and avoid agents that worsen neuromuscular transmission. Choose IVIG 0.4 g/kg/day for 5 days or plasma exchange (5–6 exchanges), manage triggers, and titrate chronic immunotherapies. Extubation is guided by NIF, vital capacity, and clinical recovery.
Epidemiology / Risk Factors
- Risk varies by comorbidity and precipitating factors
Initial Targets
| Parameter | Target/Action |
|---|---|
| Hemodynamics | Maintain perfusion; avoid hypotension |
| Monitoring | Serial exam, labs, and imaging |
| Therapy | Start early, reassess, de‑escalate when appropriate |
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| CBC | Screen leukocytosis/anemia | Context‑specific | Trend response |
| BMP | Electrolytes/renal function | Derangements common | Replace K+/Mg2+ |
| Key imaging | Condition‑specific (CTA/MRI/Endoscopy) | See text | Do not delay when red flags |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| IVIG 0.4 g/kg/day ×5 | Immunotherapy | Days | First‑line with PLEX | Headache, thrombosis risk |
| Plasma exchange (5–6) | Immunotherapy | Days | Alternative first‑line | Access complications |
| Pyridostigmine (careful) | AChE inhibitor | Minutes | Symptom control | Secretions/bradycardia |
Prognosis / Complications
- Outcome depends on timeliness of diagnosis and definitive therapy
Patient Education / Counseling
- Explain red flags, adherence, and follow‑up plan
References
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