American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the first-line emergency treatment for patients in myasthenic crisis?

1. Glucocorticoids

2. Intravenous immunoglobulin

3. Plasmapheresis

4. Anticholinesterase inhibitors

The correct answer is: Plasmapheresis

In the context of myasthenic crisis, the initial emergency treatment focuses on rapidly improving muscle strength and respiratory function. Plasmapheresis is specifically effective in this scenario as it removes circulating antibodies that are responsible for the weakened neuromuscular transmission characteristic of myasthenia gravis. By effectively reducing the levels of acetylcholine receptor antibodies, plasmapheresis can quickly alleviate symptoms. This approach is critical in a myasthenic crisis, where respiratory muscle weakness can lead to respiratory failure, necessitating prompt intervention. Plasmapheresis can lead to a significant recovery in strength within days and is particularly beneficial when immediate and rapid improvement is required. Other treatment options like glucocorticoids and intravenous immunoglobulin are also valid treatments for myasthenia gravis but are generally used in more chronic situations rather than as an emergency first-line measure. Anticholinesterase inhibitors, while useful for managing myasthenia gravis symptoms, are not sufficient when a patient is in crisis due to the need for immediate and effective intervention to support respiratory function and overall muscle strength.