Encyclopedia / M / Multiple Sclerosis (MS)

Multiple Sclerosis (MS)

What is Multiple Sclerosis?

Multiple sclerosis (MS) is a chronic, neurological disorder characterized by destruction of the myelin sheaths, the protective outer coverings of the nerves within the central nervous system, which includes the brain, optic nerves, and spinal cord. Myelin sheaths are composed mostly of fats; they insulate the nerves and preserve the speed of electrical transmissions. In MS, patchy areas of the sheaths are destroyed and replaced by scar tissue called plaques—a process known as sclerosis—at multiple sites throughout the central nervous system, hence the name of the disorder. Sclerosis impairs electrical conduction, thus reducing or eliminating transmission of nerve impulses within the affected areas. When severe, the disease may destroy the inner cables of the nerves or axons, causing irreversible damage. What triggers this process and the exact cause or causes of MS are unknown.

MS occurs in two major forms. The more common form is known as relapsing/remitting MS, which afflicts about 70 percent of MS patients, and is characterized by a series of flare-ups or attacks that, are separated by periods of normal or near-normal health. Such remissions may be short or may last for months or years. In a few cases, remission is permanent, but many patients gradually accumulate permanent neurological deficits.

The other type of MS, chronic/progressive, gradually worsens without remission. Rarely is progression so rapid or severe that survival is limited to only months or a few years.

Women are affected by MS more often than men. Average survival after diagnosis is more than 35 years, but destruction of the myelin sheaths can eventually result in a combination of nerve, muscle, and, occasionally, brain damage. However, many people retain much of their function for years and are able to pursue a wide range of normal activities with the help of supportive therapy. Current

treatment is aimed at reducing the frequency and severity of attacks, relieving the problems caused by neurological deficits, and providing psychological support.

Even with treatment, MS relapses may still occur. During a relapse, new symptoms appear and/or usual symptoms worsen for 24 hours and up to several weeks. While MS relapses are unpredictable, taking steps to prepare can make your life easier for whenever a flare might occur. An MS relapse is triggered by inflammation that occurs in the spinal cord or brain; immune cells attack myelin, provoking inflammation or a lesion. Affected nerves delay or fail to conduct signals, causing muscle spasms and possibly a relapse of MS symptoms.

Who Gets Multiple Sclerosis?

MS is the most common neurological cause of debilitation in young people. According to the National Institute of Neurological Disorders and Stroke, about 250,000–350,000 people in the United States have been diagnosed with multiple sclerosis. Worldwide, the incidence of MS is approximately 0.1%. Northern Europe, the northern United States, southern Australia, and New Zealand have the highest prevalence, with more than 30 cases per 100,000 people. MS is more common in women and in Caucasians. The average age of onset is between 20 and 40, but the disorder may develop at any age. Children of parents with MS have a higher rate of incidence, at about 30–50 percent.


The hallmark of relapsing-remitting multiple sclerosis is unpredictable periods of exacerbation, remission, and progression. Initial symptoms of MS may be brief and mild. The first serious attack usually lasts weeks or months and occurs between the ages of 20 and 40. Symptoms can be unpredictable and vary widely from patient to patient, and may occur in combination and vary greatly over time. Symptoms can include:

  • Muscle weakness, stiffness and spasms. Muscle weaknesscan involve the arms and legs, on one side of the body (hemiparesis), both legs (paraparesis), or all four extremities (quadraparesis). Muscles in the affected area may tighten and contract spontaneously
  • Eye pain and visual disturbances, including blurry vision, loss of vision in one eye, or a

sudden inability to distinguish colors known as optic neuritis, or double vision.

  • Tingling or prickling sensations.
  • Disturbances in gait; loss of coordination.
  • Dizziness, vertigo with nausea and vomiting.
  • Slurred speech.
  • Bladder and bowel dysfunction.
  • Severe fatigue. Many people with MS experience fatigue and need to rest and sleep during the day in order to continue their activities. The degree of fatigue may not be related to the severity of other symptoms.
  • Behavioral changes including depression, mood swings, confusion or loss of memory or concentration.
  • Sexual dysfunction, including erectile dysfunction and sexual inactivity
  • Paralysis of one side of the face, or partial or complete paralysis of the body.
  • Body temperature changes. An increase in body temperature caused by hot weather, hot bath and showers, or fever can worsen symptoms or produce new ones. This occurs because elevated body temperature slows nerve impulse conduction, especially in demyelinated nerves.

Causes/Risk Factors

The cause of multiple sclerosis is unknown, but genetics and the environment may play a role. Some research suggests autoimmunity—in which the body attacks its own tissue and cells—may also contribute to the development of MS.

  • A family history of MS is associated with increased risk.
  • Environmental factors may be associated with MS; the majority of cases occur in temperate climates.
  • Some theories suggest that MS may be triggered by a virus or other infectious agent.
  • There is abundant evidence of an autoimmune component to the disease.

What If You Do Nothing?

MS is a progressive, serious neurological disorder. Untreated symptoms can interfere with daily functioning worsen and lead to other complications.


The diagnosis of MS is established when there is evidence of different lesions occurring at different points in time and no other explanation. No single diagnostic test is definitive for MS, although some tests may be used to support the diagnosis and to exclude other conditions that may mimic MS.

  • A lumbar puncture (spinal tap) can detectoligoclonal bands in cerebrospinal fluid. Oligoclonal bands result from elevated levels of the antibody immunoglobulin G (IgG) and myelin basic protein, which is a byproduct of demyelination, and are present in more than 85 percent of MS cases. In this procedure, a needle is inserted between two lower lumbar vertebrae and cerebrospinal fluid is collected and analyzed.
  • Magnetic resonance imaging can detect plaques of scar tissue even in the absence of associated symptoms.
  • Tests to detect abnormalities of vision and other sensory modalities may also be used.
  • Evoked potential tests are performed to evaluate sensory, visual, and auditory functions and detect slowed nerve impulse conduction caused by demyelination. In these tests, nerves responsible for each type of function are stimulated electronically and responses are recorded using electrodes placed over the central nervous system and peripheral nerves, such as the median nerve in the wrist or fibular nerve in the knee.


  • In the past 20 years, there has been tremendous improvements in treatment options for patients with MS. MS medications focus on reducing inflammation in the central nervous system and help lessen the severity and frequency of flare-ups.
  • Oral corticosteroids, such as prednisone, or intravenous corticosteroids, such as methylprednisolone, may be prescribed to shorten the duration and reduce the severity of attacks. Methyl-prednisolone, prednisone and dexamethasone are steroids that are meant to mimic the hormone cortisol. High doses of oral or intravenous steroids for three to five days can reduce inflammation in the nervous system, which decreases the severity and duration of symptoms, speeding recovery. Corticosteroids are highly effective for most people, but long-term use isn’t recommended, due to serious side effects that may include diabetes, weight gain, osteoporosis, and others. Mild attacks can resolve on their own and don’t’ always need to be treated.
  • Muscle relaxers such as diazepam or baclofen can help relax spastic muscles and provide pain relief.
  • Antidepressants can help treat associated depression and mood swings.
  • Your doctor may prescribe the disease-modifying drugs interferon beta-1a (Avonex, Rebif) or interferon beta-1b (Betaseron, Extavia) or glatiramer acetate (Copaxone). Oral medications such as fingolimod (Gilenya), dimethyl fumarate (Tecfidera), and terifunomide (Aubagio) have recently become available to reduce the frequency of MS relapses in adults.
  • The intravenous therapies, natalizumab (Tysabri) and alemtuzumab (Lemtrada), are powerful, but they can have significant side effects such as risks of rare, life-threatening infections and so are usually reserved for patients who have poor response to other medications. Patients receiving these medications must be watched carefully. Mitoxantrone (Novantrone) is rarely used anymore due to side effects including heart failure.
  • Symptom-management drugs treat specific ailments associated with relapsing or progressive MS. These treatments focus on particular symptoms, such as bladder problems, balance issues, muscle spasticity, fatigue and pain. For example, medications such as amantadine (Symmetrel) can help with fatigue. Effectiveness varies; people often need to try several different medications and sometimes more than one may be required.
  • Diet may have an impact in managing MS symptoms. There are two popular dietary approaches, both named after physicians who developed and studied them: The Swank diet (named after Dr. Roy Swank) and the modified McDougall Diet (named after Professor Roger McDougall). The diets share similar features. Both recommend eating fish several times a week, minimizing or avoiding other animal foods, emphasizing fresh fruits, vegetables, and whole grains, and drinking plenty of water. There is evidence of an association between MS and vitamin D deficiency, although it isn’t established if vitamin D replacement is safe or effective in treatment of MS.
  • Exercise helps keep muscles as flexible and strong as possible.
  • You may benefit from physical, occupational and/or speech therapy. Physical therapy sessions might include gait and strength-training and stretching exercises to improve muscle flexibility. Occupational therapy can strengthen vision, fine motor skills and cognitive function, improving your ability to participate in everyday activities, such as getting dressed. Speech therapy can help you build weak facial and neck muscles and reduce speech and swallowing issues. A speech pathologist can also offer advice on how to change the consistency of food or the positioning of your head and neck to make swallowing easier.
  • Avoid excessive sunbathing, heavy exertion, and hot baths, and obtain

prompt treatment for fevers; a raised body temperature may trigger or worsen symptoms. Taking a cool shower, swimming, or sitting in an air-conditioned room may relieve the severity of symptoms during an attack.

  • Psychological counseling may help patients and their families cope with depression and the lifestyle changes imposed by MS.
  • Be wary of unproven remedies, such as bee venom.

Prevention There is no known way to prevent the onset of MS.

When To Call A Doctor

Call a doctor if you develop any of the symptoms of MS, especially if you have suffered several episodes or attacks.

Reviewed by Joseph V. Campellone, M.D., Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network.