American Board of Internal Medicine (ABIM) Certification Practice Exam

In patients treated with glucocorticoids, what does weakness that persists after normalization of serum CK levels indicate?

1. Neuropathy

2. Chronic fatigue syndrome

3. Glucocorticoid-induced myopathy

4. Deconditioning syndrome

The correct answer is: Glucocorticoid-induced myopathy

Weakness that continues after serum creatine kinase (CK) levels have returned to normal in patients who have been treated with glucocorticoids is indicative of glucocorticoid-induced myopathy. This condition typically presents as muscle weakness and atrophy in patients on chronic glucocorticoid therapy, even when other markers of muscle damage, such as serum CK levels, normalize. Glucocorticoid-induced myopathy is characterized by muscle fiber damage, leading to a specific pattern of muscle weakness, often affecting proximal muscles more than distal muscles. This weakness can persist despite the restoration of CK levels, which may initially elevate due to muscle damage but do not necessarily reflect ongoing muscle impairment. In this context, other conditions like neuropathy, chronic fatigue syndrome, and deconditioning syndrome may involve weakness or fatigue, but they also tend to have different clinical features, mechanisms, and implications. Neuropathy usually encompasses sensory disturbances and may not specifically correlate with glucocorticoid use. Chronic fatigue syndrome is characterized by prolonged fatigue that is not improved by rest, while deconditioning syndrome results from immobility or reduced physical activity rather than direct medication effects. These distinctions highlight why glucocorticoid-induced myopathy is the most appropriate interpretation