American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the appropriate treatment for muscle spasms due to corticospinal tract injury from multiple sclerosis?

1. Dantrolene

2. Gabapentin

3. Baclofen

4. Cyclobenzaprine

The correct answer is: Baclofen

Muscle spasms resulting from corticospinal tract injury, such as in multiple sclerosis, often require specific treatment aimed at reducing spasticity and improving patient comfort and function. Baclofen is a muscle relaxant that acts primarily as a GABA-B receptor agonist. By enhancing the inhibitory effects of GABA in the central nervous system, baclofen effectively decreases muscle tone and spasms. This makes baclofen particularly beneficial for treating spasticity associated with neurological conditions like multiple sclerosis. The medication can be administered orally or via intrathecal delivery for patients with severe symptoms, improving the quality of life by granting better control over muscle spasms. While other medications on the list may have secondary roles in managing muscle pain or spasticity, they do not address the underlying mechanisms of muscle spasms related to corticospinal tract injury as effectively as baclofen does. Dantrolene primarily works on the skeletal muscle and is used for conditions like malignant hyperthermia, while gabapentin is typically more effective for neuropathic pain rather than spasticity. Cyclobenzaprine is mainly used for muscle spasms due to musculoskeletal conditions and does not specifically target the central spasticity seen in multiple sclerosis. Thus, baclofen is