Introduction

Multiple sclerosis is an immune-mediated disease that causes the immune system to mistakenly attack the central nervous system (CNS). MS lesions may occur in the brain, spinal cord and more rarely in cranial nerves (Haider 2019).

The National MS Society funded a study in 2019 that estimates t up to 913,925 adults are living with MS in the U.S. This is two times the number previously reported in a 1975 national study and subsequent updates. In the general U.S. population, the risk of developing MS is about 1 in 333.

This is double the original estimate. Data sources from health claims from private and public insurers used in a recent study improved the accuracy of the prevalence of MS (Culpepper, et al, 2019). The following are descriptions of significant factors:

• Initially occurs in young adults peaking around 30 years of age (Wingerchuk, 2011)
• It occurs 3:1 female to male ratio (Wallin, et el, 2019)
• People from regions near the equator, where there is a great deal of bright sunlight, generally have a much lower risk of MS than people from temperate areas such as the U.S. and Canada (NINDS, 2023).
• MS is believed to be caused by both genetic and environmental factors.

MS is often, but not always, a progressively debilitating disease. It is usually experienced as periods of exacerbation followed by partial remission of symptoms. Affected individuals experience a broad range of symptoms which vary due to the site and extent of the CNS involvement. Symptoms may include temporary or permanent cognitive, sensory and motor deficits that can significantly limit independent activities of daily living.

Historically, during the mid-1880's, Jean Martin Charcot described a disorder characterized by multiple patches or plaques of sclerosed (scarred) areas scattered throughout the CNS (brain, spinal cord and cranial nerves). Modern techniques reveal these plaques as areas of inflammation, demyelination and axonal injury.

Magnetic resonance imaging (MRI) is the primary tool used to diagnose MS. MRI is able to identify and quantify the multiple round or ovoid lesions which characterize MS. MRI studies have correlated the cumulative volume of affected tissue with prognosis.

Currently there is no way to prevent or cure MS. The goal of multiple sclerosis therapy is to alter its natural course by:

• reducing the frequency and severity of exacerbation
• extending the duration of remission.
• slowing the onset of permanent disability.

These issues and more about the care of the patient with MS are described in depth in the following sections of this course.

Reference:

Culpepper, W. J., Marrie, R. A., Langer-Gould, A., Wallin, M. T., Campbell, J. D., Nelson, L. M., et al. (2019). Validation of an algorithm for identifying MS cases in administrative health claims datasets. Neurology. 92 (10). (open access)

Haider, L., Chan, W. E., Olbert, E., Mangesius, S., Dal-Bianco, A., Leutmezer, F., Prayer, D., & Thurnher, M. (2019). Cranial Nerve Enhancement in Multiple Sclerosis Is Associated With Younger Age at Onset and More Severe Disease. Frontiers in neurology, 10, 1085. https://doi.org/10.3389/fneur.2019.01085

U.S. Department of Health and Human Services. (n.d.). Multiple sclerosis. National Institute of Neurological Disorders and Stroke (NINDS). (reviewed January 23, 2023) https://www.ninds.nih.gov/health-information/disorders/multiple-sclerosis?search-term=MS+by+state#toc-who-is-more-likely-to-get-multiple-sclerosis-

Wallin, M. T., Culpepper, W. J., Campbell, J. D., Nelson, L. M., Langer-Gould, A., Marrie, R. A., et al. (2019). The prevalence of MS in the United States. Neurology. 92(10).

Wingerchuk, D.M. (2011). Environmental factors in multiple sclerosis: Epstein-Barr virus, vitamin D, and cigarette smoking. Mt Sinai J Med. 78(2), 221-30.

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