Summary of Miastenia Gravis: ¿Cómo Manejar las Crisis? - Dra. Lina Marcela Hoyos

Summary of Key Wellness Strategies, Self-Care Techniques, and Productivity Tips for Managing Myasthenia Gravis (MG) Crisis

Understanding Myasthenia Gravis and Crisis:

• MG is an autoimmune disease causing muscular weakness due to autoantibodies affecting the neuromuscular junction.
• A myasthenic crisis involves progression to ventilatory failure, often requiring emergency respiratory support.
• Crisis can be the first manifestation or progression of known MG.

Epidemiology & Clinical Presentation:

• Average diagnosis age: ~39 years, with two incidence peaks (<30 years and >70 years).
• More common in women, especially younger patients.
• Mortality has decreased from ~20% to below 5% with improved management.
• Common symptoms: muscle fatigue, ptosis, diplopia, dysphagia, respiratory weakness.
• Fatigue worsens with activity and improves with rest and cold.

Triggering Factors for Crisis:

• Infections (most common)
• Certain medications (antibiotics, anticonvulsants, neuromuscular blockers, calcium channel blockers, lidocaine)
• Surgery, pregnancy, extreme temperatures
• Sometimes no identifiable trigger (~40% cases)

Clinical Assessment & Red Flags:

• Monitor respiratory rate carefully as an early sign of deterioration.
• Warning signs include:
  • Fever or recent infection/antibiotic use
  • Decreased tidal volume
  • Nasal voice or nasal regurgitation
  • Ineffective cough
  • Increased secretions
  • Weight loss from dysphagia
• Physical tests to assess fatigue and respiratory function:
  • Forced vital capacity (FVC) measurement sitting and supine
  • Maximum inspiratory pressure (MIP)
  • Counting inspiration (patient counts aloud on one breath; <20 is concerning)
  • Holding gaze for 30-60 seconds
  • Head lift test in supine position for 30 seconds
• Ice test for ptosis: placing ice on eyelid improves ptosis if MG positive.

Diagnostic Workup:

• Antibody testing (acetylcholine receptor, muscle kinase, low-density protein 4)
• Neurophysiological tests (repetitive nerve stimulation, single fiber electromyography)
• Imaging: Chest CT to evaluate thymus and lung status
• Labs: renal, liver, thyroid function, electrolytes, beta-hCG in women of childbearing age, ECG

Respiratory Support & Ventilation:

• Ventilatory failure is mixed hypoxic and hypercapnic.
• Poor prognostic indicators for intubation include:
  • FVC < 20 ml/kg
  • MIP < -30 cm H2O
  • Max expiratory pressure < 40 cm H2O
• Non-invasive ventilation (NIV), especially BiPAP, can reduce need for intubation in selected patients.
• NIV contraindicated or likely to fail in patients with:
  • Altered consciousness or lethargy
  • Excessive secretions
  • Severe hypercapnia (PaCO2 > 45-50 mmHg)
• Intubation and invasive ventilation required if NIV fails or patient deteriorates.

Pharmacological & Immunotherapy Management:

• Avoid Acetylcholinesterase inhibitors during acute crisis due to unpredictable effects and increased secretions.
• Immunotherapy options:
  • Intravenous immunoglobulin (IVIG): rapid onset, improves symptoms within a week, lasts weeks.
  • Plasmapheresis: removes pathogenic antibodies, rapid effect lasting ~4 weeks.
• IVIG and Plasmapheresis have comparable efficacy; used based on availability and patient factors.
• Steroids: continue if already on them; start only after immunotherapy to avoid symptom worsening.
• Immunosuppressants have delayed effect; used for long-term management.
• Avoid combining IVIG and Plasmapheresis simultaneously as Plasmapheresis removes immunoglobulin.

Supportive Care:

• Monitor and maintain glycemic control.
• Provide nutritional support.
• Use thromboprophylaxis to prevent clots.
• Monitor for and treat infections, cardiovascular complications, and atelectasis.
• Early recognition and management in high-dependency or intensive care units is critical.

Prognosis and Follow-up:

• Early diagnosis and treatment reduce mortality.
• Regular pulmonary function monitoring helps detect deterioration early.
• Diaphragmatic ultrasound may be useful for early detection of respiratory muscle weakness.
• Aim to minimize duration of mechanical ventilation.

---

Key Takeaways (Bullet Points)

• Recognize early signs of myasthenic crisis: respiratory distress, fatigue, dysphagia, ineffective cough.
• Monitor respiratory function: respiratory rate, Forced vital capacity, inspiratory pressures, and counting inspiration.
• Avoid precipitating medications and treat infections promptly.
• Use non-invasive ventilation cautiously, with close monitoring for failure signs.
• Intubate early if signs

Notable Quotes

— 00:00 — « No notable quotes »

Category

Wellness and Self-Improvement

Video