From the Guidelines
Myasthenic crisis is commonly precipitated by several factors, including infections, medication use, and physiological stress, with the most recent evidence suggesting that certain antibiotics, cardiovascular drugs, and anesthetics can worsen neuromuscular transmission 1.
Precipitants of Myasthenic Crisis
The following factors can precipitate myasthenic crisis:
- Infections, particularly respiratory infections like pneumonia and bronchitis
- Medication use, including:
- Certain antibiotics (fluoroquinolones, aminoglycosides, macrolides) 1
- Cardiovascular drugs (beta-blockers, calcium channel blockers)
- Anesthetics
- Magnesium-containing products
- Some psychiatric medications
- Surgical procedures and general anesthesia
- Pregnancy, emotional stress, and extreme physical exertion
- Abrupt withdrawal of immunosuppressive medications or acetylcholinesterase inhibitors
- Temperature extremes, particularly heat
- Concurrent autoimmune disorders, trauma, and even vaccination
Management of Myasthenic Crisis
According to the most recent evidence, management of myasthenic crisis involves:
- Holding immune checkpoint inhibitors and resuming only if symptoms resolve 1
- Consulting neurology
- Offering pyridostigmine starting at 30 mg PO three times a day and gradually increasing to a maximum of 120 mg orally four times a day as tolerated and based on symptoms 1
- Administering corticosteroids (prednisone 0.5 mg/kg orally daily) and weaning based on symptom improvement 1
- Considering inpatient care and ICU-level monitoring for severe cases 1
From the Research
Precipitants for Myasthenic Crisis
- Infection is the most common precipitant for myasthenic crisis, as stated in 2
- Other stressors can also exacerbate myasthenia gravis and lead to myasthenic crisis, including 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, as mentioned in 3
- Approximately 30%-40% of patients with myasthenic crisis do not have a specific trigger, as noted in 4
- Patients with a history of myasthenic crisis, severe disease, oropharyngeal weakness, muscle-specific kinase (MuSK) antibodies, and thymoma appear to be at higher risk for myasthenic crisis, as stated in 4
Common Precipitating Factors
- Respiratory infections, as mentioned in 2, 4, 3
- Aspiration, as noted in 3
- Sepsis, as mentioned in 3
- Surgical procedures, as stated in 3
- Rapid tapering of immune modulation, as mentioned in 3
- Beginning treatment with corticosteroids, as noted in 2, 3
- Exposure to drugs that may increase myasthenic weakness, as mentioned in 3
- Pregnancy, as stated in 3