American Board of Internal Medicine (ABIM) Certification Practice Exam

What type of muscle impairment could indicate glucocorticoid-induced myopathy?

1. Increased muscle strength

2. Dehydration-related weakness

3. Persistent weakness despite treatment

4. Inactive muscle response

The correct answer is: Persistent weakness despite treatment

Persistent weakness despite treatment is a hallmark characteristic of glucocorticoid-induced myopathy. This condition is often seen in patients who have been on glucocorticoid therapy for an extended period. The main feature of this myopathy is muscle weakness that can affect proximal muscles more significantly than distal ones, leading to difficulties with tasks that require the use of larger muscle groups, such as climbing stairs or lifting objects. Glucocorticoids can cause atrophy and dysfunction of muscle fibers, particularly type II fibers, which are responsible for rapid and powerful muscle contractions. As a result, even when a patient is receiving treatment or physical therapy intended to restore muscle strength, the underlying muscle impairment persists, resulting in continued weakness. This ongoing weakness distinguishes glucocorticoid-induced myopathy from other conditions that might cause muscle weakness, where improvement or recovery may be observable with proper intervention. The recognition of this symptom is crucial for clinicians so they can adjust treatment strategies accordingly, potentially reducing glucocorticoid dosages or exploring alternative therapies.