A young patient presents with trigeminal neuralgia. Which test should be ordered to evaluate for another possible condition, such as multiple sclerosis?

• A. Nerve conduction study
• B. CXR
• C. MRI
• D. EKG

Answer: (C)

In a young patient with trigeminal neuralgia, it’s important to consider secondary causes such as multiple sclerosis. MRI of the brain (often with gadolinium contrast) is the best test to evaluate for MS because it can reveal demyelinating plaques along the trigeminal pathways, brainstem, or other CNS regions that would explain facial pain as a manifestation of central nervous system disease. Detecting these lesions guides diagnosis and management, since MS-related trigeminal neuralgia may require disease-modifying therapy in addition to pain control.

Other tests aren’t targeted for this purpose: nerve conduction studies assess peripheral nerves and are not sensitive for central demyelination; chest X-ray and EKG don’t help identify CNS demyelinating disease or MS. Therefore, MRI of the brain with contrast is the most appropriate initial test to evaluate for MS in this context.