In multiple sclerosis, patches of myelin (the substance that covers most nerve fibers) and underlying nerve fibers in the brain, optic nerves, and spinal cord are damaged or destroyed.
- The cause is unknown but may involve an attack by the immune system against the body’s own tissues (autoimmune reaction).
- Usually, periods of relatively good health alternate with episodes of worsening symptoms.
- People may have vision problems and abnormal sensations, and movements may be weak and clumsy.
- Usually, doctors base the diagnosis on symptoms and results of a physical examination and magnetic resonance imaging.
- Treatment includes corticosteroids, drugs that help keep the immune system from attacking the myelin sheath, and drugs to relieve symptoms.
- Often, the disorder slowly worsens, disabling some people, but lifespan is unaffected unless the disorder is very severe.
The term “multiple sclerosis” refers to the many areas of scarring (sclerosis) that result from destruction of the tissues that wrap around nerves (myelin sheath). This destruction is called demyelination. Sometimes the nerve fibers that send messages (axons) are also damaged. Over time, the brain may shrink in size because axons are destroyed.
In the United States, about 400,000 people, mostly young adults, have multiple sclerosis. About 10,000 new cases are diagnosed each year. Worldwide, about 2.5 million people have multiple
Most commonly, multiple sclerosis begins between the ages of 20 and 40, but it can begin anytime between ages 15 and 60 years. It is somewhat more common among women. Multiple sclerosis is
rare in children.
Most people have periods of relatively good health (remissions) alternating with periods of worsening symptoms (flare-ups or relapses). Relapses can be mild or debilitating. Recovery during
remission is good but incomplete. Thus, the disorder worsens slowly over time.
- Drugs that help keep the immune system from attacking myelin sheaths
- Measures to control symptoms
For an acute attack, corticosteroids are most commonly used. They probably work by suppressing the immune system. They are given for short periods to relieve immediate symptoms (such as loss of vision, strength, or coordination) if the symptoms interfere
with functioning. For example, prednisone may be taken by mouth, or methylprednisolone may be given intravenously. Although corticosteroids may
shorten relapses and slow the progression of multiple sclerosis, they do not stop its
progression. Corticosteroids are rarely used for a long time because they can have many side effects, such as increased susceptibility to infection, diabetes, weight gain, fatigue, osteoporosis, and ulcers. Corticosteroids are started and stopped as needed.
Drugs to help control the immune system
Drugs that help keep the immune system from attacking myelin sheaths are usually also used. These drugs help reduce the number of future relapses. They include the following:
- Interferon-beta injections reduce the frequency of relapses and may help delay disability.
- Glatiramer acetate injections may have similar benefits for people with early mild multiple sclerosis.
- Mitoxantrone, a chemotherapy drug, can reduce the frequency of relapses and slow the progression of the disorder. It is given for only up to 2 years and only when other drugs do not work because it can eventually lead to heart damage.
- Natalizumab is an antibody given intravenously as an infusion once a month. It is more effective than other drugs in reducing the number of relapses and preventing further damage in the brain. However, natalizumab may increase the risk of a rare, fatal infection of the brain and spinal cord (progressive multifocal leukoencephalopathy). Natalizumab is used only by specially trained doctors, and people who take it must be checked periodically for signs of progressive multifocal leukoencephalopathy. Blood tests for the JC virus, which causes progressive multifocal leukoencephalopathy, are done periodically.
- Alemtuzumab (used to treat leukemia) is effective in treating multiple sclerosis that occurs in relapsing patterns (relapsing-remitting pattern and progressive relapsing pattern). It is given intravenously. However, it increases the risk of
serious autoimmune disorders and certain cancers. Consequently, alemtuzumab is usually used only when treatment with two or more other drugs has been ineffective.
- Immune globulin, given intravenously once a month, occasionally helps when other drugs have been ineffective.
- Fingolimod, teriflunomide, and dimethyl fumarate, which are relatively new drugs, may be used to treat multiple sclerosis that occurs in relapsing patterns. These drugs can be taken by mouth.
- Daclizumab is a monoclonal antibody used to treat multiple sclerosis that occurs in relapsing patterns. It is given as an injection under the skin once a month. It can cause liver damage.
Plasma exchange is recommended by some experts for severe relapses not controlled by
corticosteroids. However, the benefits of plasma exchange have not been established.
For this treatment, blood is withdrawn, abnormal antibodies are removed from it, and
the blood is returned to the person.
Other drugs can be used to relieve or control specific symptoms:
- Muscle spasms: The muscle relaxants baclofen or tizanidine
- Urinary incontinence: Oxybutynin or tamsulosin
- Pain due to abnormalities in nerves: Anticonvulsants (such as gabapentin, pregabalin, or carbamazepine), sometimes tricyclic antidepressants (such as amitriptyline), or opioids
- Tremors: The beta-blocker propranolol
- Fatigue: Amantadine (used to treat Parkinson disease) or, less often, drugs used to treat excessive sleepiness (such as modafinil, armodafinil, or amphetamine)
- Depression: Antidepressants such as sertraline or amitriptyline, counseling, or both
- Constipation: Stool softeners or laxatives taken regularly People with urine retention can learn to catheterize themselves and thus empty their bladder.
People with multiple sclerosis can often maintain an active lifestyle, although they may tire easily and may not be able to keep up with a demanding schedule. Encouragement and reassurance help.
Regular exercise such as riding a stationary bicycle, walking, swimming, or stretching reduces spasticity and helps maintain cardiovascular, muscular, and psychologic health.
Physical therapy can help with maintaining balance, the ability to walk, and range of motion and can help reduce spasticity and weakness. People should walk on their own for as long as possible. Doing so improves their quality of life and helps prevent depression.
Avoiding high temperatures—for example, by not taking hot baths or showers—can help because heat can worsen symptoms. People who smoke should stop. Because people who have low levels of vitamin D tend to have more severe multiple sclerosis and because taking vitamin D may reduce the risk of developing osteoporosis, doctors usually recommend that people take vitamin D supplements. Whether vitamin D supplements can help slow the progression of multiple sclerosis is being studied. People who become weak and unable to move easily may develop pressure sores, so they and their caregivers must take extra care to prevent the sores.
If people are disabled, occupational therapists can help with rehabilitation. They can help people learn to function despite disabilities caused by the disorder. Social workers can recommend and help arrange for needed services and equipment.
- Multiple Sclerosis Association of America (MSAA)
- Merck Manuals – Multiple Sclerosis
- National Multiple Sclerosis Society