Multiple sclerosis (MS) affects women more than men. The disorder is most commonly diagnosed between ages 20 and 40, but can be seen at any age.
MS is caused by damage to the myelin sheath , the protective covering that surrounds nerve cells. When this nerve covering is damaged, nerve impulses are slowed down or stopped.
The nerve damage is caused by inflammation. Inflammation occurs when the body's own immune cells attack the nervous system. Repeated episodes of inflammation can occur along any area of the brain, optic nerve, and spinal cord.
Researchers are not sure what triggers the inflammation. The most common theories point to a virus or genetic defect, or a combination of both.
Geographic studies indicate there may be an environmental factor involved.
People with a family history of MS and those who live in a geographical area where MS is more common have a slightly higher risk of the disease.
Symptoms vary, because the location and severity of each attack can be different. Episodes can last for days, weeks, or months. These episodes alternate with periods of reduced or no symptoms (remissions).
Fever, hot baths, sun exposure, and stress can trigger or worsen attacks.
It is common for the disease to return (relapse). However, the disease may continue to get worse without periods of remission.
Because nerves in any part of the brain or spinal cord may be damaged, patients with multiple sclerosis can have symptoms in many parts of the body.
There is no known cure for multiple sclerosis at this time. However, there are therapies that may slow the disease. The goal of treatment is to control symptoms and help you maintain a normal quality of life.
Medications used to slow the progression of multiple sclerosis are taken on a long-term basis, they include:
Interferons (Avonex, Betaseron, or Rebif), glatiramer acetate (Copaxone), mitoxantrone (Novantrone), and natalizumab (Tysabri)
The outcome varies, and is hard to predict. Although the disorder is chronic and incurable, life expectancy can be normal or almost normal. Most people with MS continue to walk and function at work with minimal disability for 20 or more years.
The following typically have the best outlook:
People who were young (less than 30 years) when the disease started
People with infrequent attacks
People with a relapsing-remitting pattern
People who have limited disease on imaging studies
The amount of disability and discomfort depends on:
How often you have attacks
How severe they are
The part of the central nervous system that is affected by each attack
Most people return to normal or near-normal function between attacks. Slowly, there is greater loss of function with less improvement between attacks. Over time, many require a wheelchair to get around and have a more difficult time transferring out of the wheelchair.
Those with a support system are often able to remain in their home.
The condition deteriorates to the point where home care is no longer possible
Review Date: 8/5/2010.
Reviewed by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. Previously reviewed by Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital.