Unknown: Multiple Sclerosis

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Unknown: Multiple Sclerosis

Causes and Symptoms
The Future
For more information


Multiple sclerosis, or MS, is a disorder in which the nerves in the central nervous system gradually lose their protective covering of myelin, a fatty substance that insulates the nerves and allows them to transmit messages to and from the brain. The damaged myelin forms scar tissue, or sclerosis, which gives the disease its name. When the myelin is damaged, transmission of nerve impulses is not only delayed but may also be misinterpreted by the brain. The result is an assortment of visual disturbances, problems with movement, hearing difficulties, fatigue, strange sensations in the arms and legs, and other symptoms that vary from patient to patient. MS is an autoimmune disorder, which means that it is caused by the body attacking itself.


One of the most confusing aspects of MS is that some patients are only mildly affected by the disease for many years, while others become almost completely disabled over time. To help explain the different forms that multiple sclerosis may take, the National Multiple Sclerosis Society standardized four subtypes of MS in 1996. These subtypes are used to determine treatment and predict the future course of the disease:

  • Relapsing-remitting (RR). About 85 percent of patients with MS have this form of the disease. The patient has occasional attacks (also called relapses) in which symptoms get worse, followed by periods of remission in which the patient has stable health.
  • Primary progressive (PP). About 10 percent of MS patients are in this category. In PP multiple sclerosis, the disease gets worse over time from the beginning with no distinct relapses or remissions.
  • Secondary progressive (SP). Patients with the SP form of the disease start out with the relapsing-remitting form and then develop the primary-progressive form. Between half and three-quarters of

    patients with RR multiple sclerosis develop the SP form within ten years. It is not yet known whether recently introduced drugs to treat MS will change this pattern. SP is the subtype that causes the greatest disability.
  • Progressive relapsing (PR). About 5 percent of patients with MS have the progressive relapsing type. They get steadily worse from the beginning with periodic attacks of more severe symptoms along the way.

In addition to these four subtypes of MS, there is also a category called clinically isolated syndrome or CIS. It is used to refer to people who most likely have relapsing-remitting MS but have had only one episode of illness and do not yet meet all the criteria for a diagnosis of MS. People with a CIS may or may not go on to develop MS.


According to the National Institute of Neurological Disorders and Stroke (NINDS), there are between 250,000 and 300,000 people who have been diagnosed with MS in the United States, with about 200 cases diagnosed each week. There are likely to be many others, however, in the early stages of the disease whose symptoms are too mild or too uncertain to lead to a diagnosis of MS. Worldwide, the rate of MS varies from country to country, ranging between two and 150 per 100,000 people; it is estimated that there are 2.5 million people around the world with MS.

Multiple sclerosis is almost entirely a disease of adults. It is most likely to affect people between the ages of twenty and fifty, with the average age at onset being thirty-four years. It is more common among Caucasians of northern European background than among African Americans or Native Americans. Some ethnic groups, such as the Inuit of Alaska and the Maoris of New Zealand, rarely develop MS. MS is twice as likely to affect women as men. Men, however, are more likely to develop the primary progressive form of the disease.

Causes and Symptoms

Although researchers know that the symptoms of MS are caused by damage to the myelin coverings of nerve fibers, they have not been able to determine what causes the damage to the myelin initially. One theory holds that infection by some kind of virus turns the body's immune system against the myelin sheaths along the nerve endings. Other researchers think that it may be a bacterial infection that triggers MS. Still another theory involves a possible role of vitamin D in the development of the disease. Vitamin D is produced in the body by exposure to sunlight, which is more abundant in countries closer to the equator than in those closer to the poles. People in the tropics have higher levels of vitamin D in their bodies and lower rates of MS. It is thought that this vitamin boosts the immune function and may help protect against autoimmune diseases like MS.

In addition to possible infectious and environmental causes, researchers think that genetic factors play some role in MS even though the disease is not directly inherited. Although the risk of developing MS in the general population is one in 750, the risk rises to one in forty in anyone who has a first-degree relative (parent, sibling, or child) with the disease. An identical twin of a patient with MS has about one in four chance of developing the disease.

A Writer Reflects on Life with MS

Joan Didion (1934–) is an American writer of novels and screenplays who was diagnosed with MS in the 1980s. Although she has a relatively mild form of the relapsing-remitting form of the disease, she observes that the emotional impact of MS can be intense: “The knowledge that one has a potentially serious and debilitating disease—no matter how benign a form it seems to be taking—does change one's life and requires a significant adjustment.… One can certainly overreact or make the disease the centerpiece of one's life, and I am by no means advocating that, but the difficulty of coming to terms with it should not be understated.”

Didion continues: “The primary task [for me] was learning to live with day to day uncertainty. Uncertainty about tomorrow requires more immediate adjustment. It is easy to feel anger and frustration when, because one's physical capacity varies so from day to day, plans cannot always be carried out. It becomes even more necessary than usual to know one's priorities. The need to establish priorities is common to everyone but becomes more acute under the pressure of this level of daily uncertainty. I also discovered that my expectations of what I should be capable of were getting in my way. I had to learn to adjust those expectations to the reality of what I was capable of and, more important, to understand that who I was did not depend on what I could do physically.”

The symptoms of MS may include some or most of the following, depending on which parts of the nervous system have been damaged by the loss of myelin:

  • Fatigue. It is not unusual for patients with MS to be too weak to carry groceries upstairs or go for a walk. Fatigue affects about 80 percent of patients with MS.
  • Visual problems, including seeing double, blurry vision, or pain in the eyes. Visual problems are often the first noticeable symptom of MS.
  • Problems with gait, balance, and coordination.
  • Bladder and bowel dysfunction, including constipation, diarrhea, and inability to control urination.
  • Dizziness.
  • Changes in mental function, including memory loss and difficulty concentrating.
  • Sexual dysfunction and loss of interest in sex.
  • Depression and rapid mood changes.
  • Spasticity. Spasticity refers to muscle stiffness and involuntary spasms of the muscles.
  • Numbness in the limbs or face. Some patients may also experience tingling or itching sensations.
  • Less common symptoms of MS include loss of hearing; headaches; speech disorders; swallowing problems; and seizures.


There is no single test that can be used to diagnose MS. It is essentially a diagnosis of exclusion, which means that the doctor arrives at the diagnosis by first ruling out other possible causes of the patient's symptoms. The doctor usually begins by taking a complete history of the patient's symptoms and looking for a possible pattern in their occurrence. Other tests that may be used to clarify the diagnosis include:

  • A neurological examination. The doctor will test the patient'sgait (habitual manner of walking), reflexes, muscle tone and strength, perceptions of heat, cold, and vibration, and coordination and balance.
  • Psychiatric examination. This may be given to test for memory loss and other disorders of thought. It may also be given to rule out depression or other psychiatric disorders that may cause fatigue, loss of sexual interest, and other symptoms experienced by some patients with MS.
  • Multiple resonance imaging (MRI). This imaging technique can reveal lesions in the brain caused by the loss of myelin.
  • Spinal tap. This is a procedure in which the doctor withdraws a sample of cerebrospinal fluid through a needle inserted into the spinal column. It can be used to look for an abnormally high level of white blood cells and certain proteins that are characteristic of MS, or to rule out other possible disorders of the central nervous system.
  • Evoked potential (EP) testing. These are tests that record the nervous system's electrical responses to specific forms of sensory stimulation, usually visual, hearing, and general sensory perception.

After ruling out other possible causes of the patient's symptoms, the doctor can base a diagnosis of MS on showing that damage has occurred to the myelin in at least two separate areas of the central nervous system and that the areas of damage occurred at least one month apart.


There is no cure for MS. The disease is managed by the use of drugs intended to modify the course of the disease; treat initial symptoms and relapses; improve the patient's safety and ability to function through physical rehabilitation; and provide emotional support.

Therapy for MS may include:

  • Disease-modifying drugs. There are six of these that were approved by the Food and Drug Administration (FDA) as of 2008. These compounds are intended to slow the progression of MS and postpone relapses. They cannot, however, be taken by women who are pregnant or planning a pregnancy.
  • Drugs to treat specific symptoms. Spasticity can be treated with muscle relaxants; visual symptoms often respond well to a drug called Solu-Medrol; fatigue can be treated by antidepressants; and muscle or back pain can be treated with aspirin with or without codeine.
  • Relapses are most often treated with cortisone and other steroid medications.
  • Rehabilitation for patients with MS may include several types of therapy depending on the patient's specific symptoms. Occupational therapy, physical therapy, speech therapy, and training for a different occupation may all be needed.

Patients with MS are often advised to avoid hot showers, saunas, or hot tubs, and vigorous exercise, as heat appears to trigger relapses of the disease. Those who live in hot, humid climates should have an air conditioner in at least one room of their house.

Some patients with MS benefit from complementary and alternative (CAM) treatments, including yoga, relaxation techniques, hypnosis, meditation practice, pet therapy, and humor therapy.


The prognosis for MS varies; most patients are relatively symptom-free and able to complete school or work for almost twenty years. The patients with a more favorable prognosis are those who are female; those who are younger than thirty when their symptoms started; those who have infrequent attacks; those who have the relapsing-remitting form of the disease; and those who have less severe symptoms.

Patients are more likely to die from complications associated with MS than from the disease itself. However, it is estimated that the disease shortens a patient's life span by about seven years.


There is no known way to prevent MS.

The Future

Researchers are working on a definitive diagnostic test for MS as well as better treatments and an improved understanding of the role of the immune system in the disease process. Some scientists think that identification of the genetic factors involved in the disease combined with further study of environmental factors may help find ways to prevent the disease.


Clinically isolated syndrome (CIS) : A term applied to patients who have had one episode of illness that suggests they have MS but do not yet meet the full criteria for diagnosis.

Myelin: A fatty substance that insulates nerve fibers and allows for speedy and accurate transmission of nerve impulses.

Progressive: A term that refers to a disease that gets worse over time. MS is a progressive disease.

Relapse: A return or recurrence of the symptoms of a disease.

Remission: A period of relief from the symptoms of a disease.

Sclerosis: Hardening or scarring of tissue.

Spasticity: Stiffness or spasms in the muscles.

SEE ALSO Cerebral palsy

For more information


Birnbaum, Gary. Multiple Sclerosis. New York: Oxford University Press, 2008. Brill, Marlene Targ. Multiple Sclerosis. Tarrytown, NY: Marshall Cavendish Benchmark, 2008.

Furney, Kym Orsetti. When the Diagnosis Is Multiple Sclerosis: Help, Hope, andInsights from an Affected Physician. Westport, CT: Praeger Publishers, 2008.

Webster, Barbara D. All of a Piece: A Life with Multiple Sclerosis. Baltimore: Johns Hopkins University Press, 1989.


Als, Hilton. “Profiles: A Pryor Love.” New Yorker, September 13, 1999. Available online at http://www.newyorker.com/archive/1999/09/13/1999_09_13_068_TNY_LIBRY_000019041?currentPage=all (accessed June 8, 2008). This is a profile of the comedian Richard Pryor, diagnosed with multiple sclerosis in 1986 and forced to retire in 1994.


Didion, Joan. “After the Diagnosis.” In All of a Piece: A Life with Multiple Sclerosis,by Barbara D. Webster. Baltimore: Johns Hopkins University Press, 1989. Available online at http://www.lifewithms.com/after~1.htm (updated August 17, 2007; accessed June 8, 2008). This is an essay by a well-known American writer about living with multiple sclerosis, excerpted from a book about the disease.

Mayo Clinic. Multiple Sclerosis. Available online at http://www.mayoclinic.com/health/multiple-sclerosis/DS00188 (updated December 6, 2006; accessed June 7, 2008).

National Institute of Neurological Disorders and Stroke (NINDS). Multiple Sclerosis: Hope through Research. Available online at http://www.ninds.nih.gov/disorders/multiple_sclerosis/detail_multiple_sclerosis.htm (updated April 8, 2008; accessed June 7, 2008).

National Multiple Sclerosis Society. About MS. Available online at http://www.nationalmssociety.org/about-multiple-sclerosis/index.aspx (accessed June 8, 2008).

Virtual Medical Centre. 3D Animation of Multiple Sclerosis. Available online at http://www.virtualrenalcentre.com/diseases.asp?did=159 (accessed June 8, 2008). The animation takes about a minute and a half to play.