top of page

How Demyelination in MS Impacts the Body

Written by Irene Wang, Edited by Olivia N. McCollum

Introduction  

Multiple sclerosis (MS) is an autoimmune disorder and is the leading cause of disability in young adults ages 20 to 40.1 The disease occurs when the immune system attacks the myelin sheath, the protective fatty layer that insulates axons in the brain and spinal cord, disrupting communication between the central nervous system and the rest of the body.2 Symptoms vary from person to person but often include difficulty walking, muscle weakness, memory issues, and vision problems.1 Currently, the exact cause of MS remains unknown. However, research continues to try and answer the lingering questions about this disorder, exploring potential treatments for slowing its progression and ways to alleviate symptoms.


Overview of MS

MS damages the protective myelin that surrounds axons, leading to impaired sensory, motor, and visual functions.3 Because myelin is found throughout the central nervous system (CNS), the effects of demyelination can be widespread. Symptomatic episodes, also called attacks, are characterized by muscular weakness, stiffness, and painful spasms that may progress to partial or complete paralysis in the arms and legs.1 Attacks may vary in duration, lasting from a minimum of 24 hours to several months.4 


While the causes of MS remain uncertain, several correlates have been considered. According to a recent study by Langer-Gould, a cohort of more than 2.6 million adults in Southern California showed that 76.8% of individuals with MS were women. The study also found that MS prevalence was similarly high among White and Black adults–refuting earlier research that suggested MS was predominantly a disease of White populations and highlighting the historically understudied burden of MS in the U.S. Black community.5


Environmental and lifestyle factors, such as increased vitamin D, appear to reduce the risk of developing MS, while other factors like smoking have been attributed to a higher risk of developing a more aggressive form of MS.1 


Diagnosis of MS typically involves a combination of MRI scans, lumbar punctures, and physical and neurological examinations, which help detect characteristic lesions in the brain and spinal cord of the patient.1


Demyelination in MS

Neurons, the primary cells of the CNS, transmit electrical signals that control both voluntary and involuntary processes in our body–from intentional movement to heartbeat regulation.6 Each neuron consists of a cell body with dendrites that receive incoming signals, and a long structure called the axon that carries impulses to other neurons or organs. Depending on the neuron’s function, an axon can be as short as a few millimeters or reach up to a meter.7 


To facilitate rapid signal transmission from the brain to other parts of the body, axons are insulated with myelin sheaths–lipid-rich layers produced by oligodendrocytes.3 The sheaths allow electrical impulses to “jump” between exposed segments of the axon, enabling rapid signal transmission. In MS, the immune system attacks these healthy sheaths and the cells that produce them, leading to inflammation, nerve fiber damage, and symptoms such as clumsiness, paralysis, visual disturbances, and dizziness.1 Communication between organs becomes significantly impaired, explaining why MS attacks can be so damaging.


Types of MS

MS is typically categorized into four types: Relapsing-remitting MS (RRMS), Secondary-progressive MS (SPMS), Primary-progressive MS (PPMS), and Clinically isolated syndrome (CIS).8 Most patients are initially diagnosed with RRMS and present with acute worsening of neurological symptoms and relapses. These relapses involve acute demyelination and are usually associated with new lesions forming in the brain or spinal cord.8 SPMS usually develops from RRMS and has a gradual worsening of symptoms over time, with or without relapses. Demyelination in SPMS progresses steadily over time. In PPMS, there are no clear relapses or remissions, only steady neurological deterioration from the onset of the disease.8 Finally, CIS is characterized by a single attack followed by complete or near-complete recovery.1


Current treatment options for MS

MS treatment is typically split into three categories: managing relapses, controlling symptoms, and modifying long-term disease progression. Acute relapses are often treated with corticosteroids, which suppress the immune response and reduce inflammation in the CNS.1 Steroid administration does not shorten long-term progression of MS. Instead, it shortens the length of the relapse—which may last from a few days to months—and can also lessen the severity of the relapse.9 Treating the symptoms of MS may involve physical therapy, individual symptom-specific medications, rehabilitation, counseling, and exercise to maintain function and quality of life. Long-term treatments rely on disease-modifying therapies (DMTs) to slow disease activity, which often reduces inflammation in the CNS and the number and severity of relapses.9

References


  1. Multiple Sclerosis | National Institute of Neurological Disorders and Stroke. Accessed October 11, 2025. https://www.ninds.nih.gov/health-information/disorders/multiple-sclerosis

  2. Rizvi S. Multiple sclerosis: moving towards a cure. Brown Health University. Published December 10, 2024. Accessed October 11, 2025. https://www.brownhealth.org/be-well/multiple-sclerosis-moving-towards-cure

  3. Stadelmann C, Timmler S, Barrantes-Freer A, Simons M. Myelin in the central nervous system: structure, function, and pathology. Physiological Reviews. 2019;99(3):1381-1431. doi:10.1152/physrev.00031.2018

  4. MyMSTeam. How long does an MS flare last? Accessed November 24, 2025. https://www.mymsteam.com/resources/how-long-does-an-ms-relapse-last

  5. Langer-Gould AM, Gonzales EG, Smith JB, Li BH, Nelson LM. Racial and ethnic disparities in multiple sclerosis prevalence. Neurology. 2022;98(18):e1818-e1827. doi:10.1212/WNL.0000000000200151

  6. Institute for Quality and Efficiency in Health Care (IQWiG). How does the nervous system work? In: InformedHealth.org. Published 2023. Accessed October 11, 2025. https://www.ncbi.nlm.nih.gov/books/NBK279390/

  7. Purves D, Augustine GJ, Fitzpatrick D, Hall WC, LaMantia AS, White LE. Nerve cells. In: Neuroscience. 2nd ed. Sinauer Associates; 2001. Accessed October 11, 2025. https://www.ncbi.nlm.nih.gov/books/NBK11103/

  8. Klineova S, Lublin FD. Clinical course of multiple sclerosis. Cold Spring Harb Perspect Med. 2018;8(9):a028928. doi:10.1101/cshperspect.a028928

  9. Multiple Sclerosis Association of America. Introduction to treatments for multiple sclerosis. Published December 28, 2015. Accessed October 11, 2025. https://mymsaa.org/ms-information/treatments/introduction/

This post is not a substitute for professional advice. If you believe that you may be experiencing a medical emergency, please contact your primary care physician, or go to the nearest Emergency Room. Results from ongoing research are constantly evolving. This post contains information that was last updated in December 2025.


Comments

bottom of page