Multiple Sclerosis: Diagnosis

Clinical Diagnosis

Two or more clinically distinct episodes of CNS dysfunction (ie, separated in space and time) as described above, separated in time and space, in a person of the appropriate age, strongly suggests MS. Diagnostic tests, particularly brain MRI, can be helpful.

Presenting symptoms were listed previously. Additional symptoms include: 

• Fatigue.
• Heat intolerance––elevated body temperatures exacerbate symptoms (Uhthoff's phenomenon).
• Radiating “electric shock" with movement of the neck (Lhermitte's phenomenon).
• Depression and/or cognitive dysfunction.
• Dysarthria, dysphagia, and/or nystagmus.

Laboratory Tests

Diagnostic tests can also be helpful.

Brain MRI is the test of choice and may show multiple white–matter lesions. A lesion’s potential to represent MS plaques corresponds directly to its size and proximity or relationship to the cerebral ventricles. Enhancement of a lesion indicates that it has been active within the past three months. Other disease processes such as ischemia and lupus can also cause white–matter lesions.

Spinal MRI may aid diagnosis. Only 3% of spinal MRIs were abnormal in patients without MS, whereas spinal lesions usually parallel brain lesions in MS,^15,16 although they are usually less visible.

Lumbar puncture may show oligoclonal bands, myelin basic protein, or IgG abnormalities in 80% to 85% of patients with active MS.

Abnormal visual–evoked, somatosensory–evoked, or auditory–evoked potentials may be identified; visual and somatosensory findings are most helpful for diagnostic purposes.

In patients with optic neuritis, an MRI showing one or more white–matter lesions greater than 3 mm predicts the onset of MS within 10 years in 56% of cases, compared with 22% of those without such lesions.¹⁷ Overall, 39% of optic neuritis patients were shown to develop MS within 10 years, and 60% developed it in 40 years.¹⁸ Oligoclonal bands in the cerebrospinal fluid increase the likelihood that optic neuritis patients will develop MS.