From the Guidelines
Myasthenia gravis crisis requires immediate hospitalization and intensive care management, with treatment typically involving cholinesterase inhibitors, immunosuppressive therapy, and rapid immunomodulation through plasma exchange or intravenous immunoglobulin (IVIG). The most recent and highest quality study 1 recommends that patients with myasthenia gravis crisis (G3-4) should be permanently discontinued from immune checkpoint inhibitors (ICPi), admitted to the hospital, and may need ICU-level monitoring.
Treatment Approach
- Cholinesterase inhibitors like pyridostigmine should be started at 30 mg PO three times a day and gradually increased to a maximum of 120 mg PO four times a day as tolerated and based on symptoms.
- Corticosteroids (prednisone 0.5 mg/kg orally daily) should be administered, with tapering beginning 3-4 weeks after initiation and based on symptom improvement.
- IVIG (2 G/kg IV over 5 days) or plasmapheresis (3-5 days) should be initiated for rapid immunomodulation.
- Frequent pulmonary function assessment and daily neurologic review are crucial for monitoring the patient's condition.
Respiratory Support
Respiratory support is essential in managing myasthenia gravis crisis, with intubation and mechanical ventilation often necessary when forced vital capacity falls below 15mL/kg or negative inspiratory force is less than -20 cmH2O. Triggers such as infections should be identified and treated with appropriate antibiotics, and medications that can worsen myasthenia (aminoglycosides, fluoroquinolones, magnesium, beta-blockers) must be avoided.
Monitoring and Management
Close monitoring of respiratory function, including negative inspiratory force and vital capacity measurements every 4-6 hours, is essential. This comprehensive approach addresses both the immediate respiratory compromise and the underlying autoimmune process where antibodies block acetylcholine receptors at the neuromuscular junction, preventing effective muscle contraction, as noted in 1.
From the FDA Drug Label
Pyridostigmine bromide is useful in the treatment of myasthenia gravis. The treatment for myasthenia gravis crisis may involve pyridostigmine as it is useful in the treatment of myasthenia gravis 2.
From the Research
Treatment Options for Myasthenia Gravis Crisis
- Plasma exchange (PE) and intravenous immunoglobulin (IVIG) are fast-acting immunomodulatory therapies used to treat myasthenic crisis (MC) 3.
- PE is associated with a reduced ICU stay length and an early response in patients with AChR-associated MC 3.
- IVIG is associated with a significant reduction in anti-AChR antibody titers 3.
- Treatment should target the inciting event and airway support, with consideration given to noninvasive positive-pressure ventilation for ventilatory support 4.
- Corticosteroids, depolarizing paralytics, and acetylcholinesterase inhibitors should be avoided in patients with MC in the emergency department 4.
Management of Myasthenic Crisis
- Myasthenic crisis is a life-threatening state with respiratory failure in patients with myasthenia gravis (MG) 3, 4, 5.
- Common precipitating factors for myasthenic crisis include respiratory infections, aspiration, sepsis, surgical procedures, rapid tapering of immune modulation, beginning treatment with corticosteroids, exposure to drugs that may increase myasthenic weakness, and pregnancy 5.
- Myasthenic crisis should not be fatal, as long as patients receive timely respiratory support and appropriate immunotherapy to reduce myasthenic weakness of the upper airway and respiratory muscles 5.
Comparative Efficacy of Treatment Options
- Therapeutic plasma exchange (TPE) has a higher response rate than IVIG in acute MG patients and patients undergoing thymectomy 6.
- There is no difference in mortality between TPE and IVIG treatment options 6.
- Both plasma exchange and IVIG treatments have a clinically significant effect 4 weeks after treatment in patients with chronic MG, but the improvement has a more rapid onset after plasma exchange than after IVIG 7.