What is the characteristic clinical course of multiple sclerosis (MS)?

Updated: Mar 27, 2019
  • Author: James A Wilson, MD, MSc, FRCPC; Chief Editor: James G Smirniotopoulos, MD  more...
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Answer

Answer

The clinical course of MS can follow different patterns, and this observation has led to the classification of distinct types of MS. The most common form of MS is termed relapsing-remitting MS, in which progression involves symptoms of neurologic dysfunction frequently followed by partial or complete clinical recovery. In relapsing-remitting MS, global clinical deterioration has traditionally been attributed to cumulative deficit due to incomplete recovery from repeated occurrences of individual relapses. However, this cumulative deficit has been questioned, because evidence increasingly suggests an ongoing background neurologic deterioration that is independent of the relapses.

Occasionally, the course of MS may be more indolent and exhibit a chronic, persistent neurologic deficit without apparent ongoing deterioration or further impairment. Sometimes, this course of MS is called inactive or benign MS, and this form is often observed in patients with prior relapsing-remitting disease.

Another potentially complicating matter clinically is that highly active MS lesions may sometimes demonstrate significant mass effect. Rarely, mass effect can lead to midline shift, herniations, infarctions, and even death. Such a drastic clinical and radiologic presentation can lead to an incorrect preliminary diagnosis and inappropriate neurosurgical intervention. When MS presents in a more fulminant, aggressive manner, it is frequently known as malignant MS or the Marburg variant.

In a prospective study, Lebrun et al followed 70 patients who had their first brain MRI for a variety of medical symptoms not suggestive of MS and found the mean time between the first brain MRI and the first clinically isolated syndrome to be 2.3 years (range, 0.8-5 yr). Diagnostic studies of the blood, CSF, and visual evoked potentials were conducted, and clinical conversion occurred in 23 patients: 6 to optic neuritis, 6 to myelitis, 5 to brainstem symptoms, 4 to sensitive symptoms, 1 to cerebellar symptoms, and 1 to cognitive deterioration. [17] For patient education information, see Multiple Sclerosis.

In a study of cognitive impairment in MS patients by using brain MRI sequences, cognitively impaired MS patients had gray matter atrophy of the left thalamus, right hippocampus, and parietal regions. They also showed atrophy of several white matter tracts, mainly located in posterior brain regions, and widespread white matter diffusivity abnormalities. Of 61 patients with relapsing-remitting MS, 23 (38%) had cognitive impairment. [18]

A large multicenter, longitudinal study of high-resolution T1-weighted MRI scans in 1214 MS patients showed that deep gray matter volume loss drives disability accumulation in MS, and the rate of temporal cortical gray matter atrophy in secondary-progressive MS was significantly faster than in relapsing-remitting MS. [19]

Progress has been made in the development of more specific MRI markers for monitoring progressive multiple sclerosis (PMS); longitudinal studies have explored the sensitivity of these markers, such as brain atrophy. [20, 21, 22]

See Multiple Sclerosis, a Critical Images slideshow, for more information on incidence, presentation, intervention, and additional resources.


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