What are the initial management and treatment steps for a patient admitted with myasthenia gravis crisis?

Management of Myasthenia Gravis Crisis: Admission Orders Template

For patients in myasthenia gravis crisis, early intubation and mechanical ventilation is the most important step in management, followed by immunomodulatory therapy with plasmapheresis as first-line treatment. 1

Initial Assessment and Monitoring

• Vital signs: Monitor q1-2h including respiratory rate, oxygen saturation, heart rate, blood pressure
• Neurological assessment:
  • Document baseline MG symptoms and severity
  • Perform daily neurological examinations
  • Monitor for signs of worsening weakness
• Respiratory monitoring:
  • Pulmonary function tests q4-6h (FVC, NIF)
  • Arterial blood gases as needed
  • Consider early intubation for:
    • FVC <15 mL/kg
    • NIF <20 cmH2O
    • Signs of respiratory distress
    • Declining oxygen saturation
    • Inability to handle secretions

Airway Management

• Early intubation is crucial in managing myasthenic crisis 1, 2
• Prefer orotracheal approach for intubation 2
• Consider small bore duodenal tubes to reduce aspiration risk 2
• If respiratory compromise is impending but not severe, consider trial of NIV:
  • Most appropriate for patients with APACHE II score <6 and serum bicarbonate <30 mmol/L 3
  • Monitor closely for failure requiring intubation

Acute Immunomodulatory Therapy

• Plasmapheresis: First-line therapy for myasthenic crisis 1

  • Standard protocol: 5 exchanges over 7-10 days
  • Monitor for hypotension, electrolyte abnormalities

• IVIG: Alternative if plasmapheresis unavailable/contraindicated 1

  • Dose: 2 g/kg divided over 2-5 days
  • Note: Do not perform plasmapheresis immediately after IVIG 1

Medication Management

• Discontinue acetylcholinesterase inhibitors (pyridostigmine) during acute crisis 4, 5

  • Resume once patient stabilizes, typically at lower doses than pre-crisis

• Corticosteroids:

  • High-dose methylprednisolone 1-2 mg/kg IV 1
  • Warning: May initially worsen symptoms in some patients 1
  • Monitor closely for worsening after initiation

• Maintenance immunosuppression:

  • Plan for transition to prednisone and steroid-sparing agents after acute phase 1

Precipitating Factor Identification and Management

• Infection workup:

  • Blood cultures, urinalysis, chest X-ray
  • Sputum culture if productive cough
  • Avoid aminoglycosides, fluoroquinolones, macrolides 1
  • Safer alternatives: penicillins, cephalosporins, tetracyclines 1

• Medication review:

  • Discontinue medications that may exacerbate MG:
    • Beta-blockers
    • Aminoglycosides
    • Fluoroquinolones
    • Macrolides
    • Magnesium-containing products
    • Daptomycin 1

Supportive Care

• DVT prophylaxis: Mechanical or pharmacological as appropriate
• GI prophylaxis: PPI or H2 blocker
• Nutrition: Consider early enteral nutrition via small bore feeding tube
• Physical therapy: Early consultation for respiratory therapy
• Fluid management: Maintain euvolemia

Monitoring for Complications

• Differentiate between myasthenic and cholinergic crisis 4

  • Myasthenic crisis: Worsening disease requiring more anticholinesterase
  • Cholinergic crisis: Overdose of anticholinesterase requiring withdrawal
  • May require edrophonium test for differentiation 4

• Watch for extubation readiness:

  • Maximal expiratory pressure (PEmax) ≥40 cmH2O predicts successful extubation 3
  • Adequate cough strength is critical to prevent reintubation 3

Consultations

• Neurology: Immediate consultation
• ICU team: For ventilatory management
• Physical/Respiratory therapy: For chest physiotherapy and early mobilization
• Consider thymectomy evaluation for appropriate patients 1

Discharge Planning

• Plan for transition to maintenance immunosuppression
• Schedule follow-up with neurology within 1-2 weeks
• Provide patient education on MG triggers and warning signs

Common Pitfalls to Avoid

1. Delayed intubation: Liberal approach to intubation is recommended to prevent complications 2
2. Continuing acetylcholinesterase inhibitors during crisis can worsen outcomes 5
3. Administering IVIG followed by immediate plasmapheresis will remove the administered immunoglobulin 1
4. Failure to identify and treat precipitating factors, especially infections 1
5. Premature extubation without adequate assessment of respiratory muscle strength 3