American Board of Internal Medicine (ABIM) Certification Practice Exam

Which treatment is used for limb tremor in patients with multiple sclerosis?

1. Clonazepam

2. Botulinum toxin

3. Carbamazepine

4. Methylprednisolone

The correct answer is: Botulinum toxin

Botulinum toxin is used to manage limb tremors in patients with multiple sclerosis due to its ability to reduce involuntary muscle contractions. In multiple sclerosis, tremors can result from underlying neurological issues, and botulinum toxin acts by blocking the release of acetylcholine at the neuromuscular junction, effectively decreasing the hyperactivity of the muscles that contribute to tremor. This treatment is particularly beneficial in cases where the tremor is focal and affects specific areas, as botulinum toxin can be injected directly into the affected muscles, providing localized relief with minimal systemic effects. It is generally preferred in patients who do not respond adequately to other oral medications or those who experience significant side effects from them. In contrast, other treatments listed may not be effective for limb tremors specifically associated with multiple sclerosis. For example, clonazepam is primarily an anxiolytic and is used for anxiety disorders and certain types of seizures, rather than specifically targeting tremors. Carbamazepine is an anticonvulsant effective for certain types of neuropathic pain and seizures but not commonly used for managing tremors from multiple sclerosis. Methylprednisolone is a corticosteroid usually employed to treat acute exacerbations of multiple sclerosis but does not have a direct