What is multiple sclerosis?

Multiple sclerosis, often called MS, is a disease that affects the central nervous system-the brain and spinal cord. It can cause problems with muscle control and strength, vision, balance, feeling, and thinking.

Your nerve cells have a protective covering called myelin. Without myelin, the brain and spinal cord can't communicate with the nerves in the rest of the body. MS gradually destroys myelin in patches throughout the brain and spinal cord, causing muscle weakness and other symptoms. These patches of damage are called lesions.

MS is different for each person. You may go through life with only minor problems. Or you may become seriously disabled. Most people are somewhere in between. Generally, MS follows one of four courses:

• Relapsing-remitting, where symptoms fade and then return off and on for many years.
• Secondary progressive, which at first follows a relapsing-remitting course and then becomes progressive. "Progressive" means it steadily gets worse.
• Primary progressive, where the disease is progressive from the start.
• Progressive relapsing, where the symptoms come and go but nerve damage steadily gets worse.

Whatever your symptoms are, treatment and self-care can help you maintain your quality of life. There is no cure for MS, but it is not fatal except in rare cases.

What causes MS?

The exact cause is unknown, but most experts believe MS is an autoimmune disease. In this kind of disease, the body’s defenses, called the immune system, mistakenly attack normal tissues. In MS, the immune system attacks the central nervous system-the brain and spinal cord.

Experts don't know why MS happens to some people but not others. There may be a genetic link, because the disease seems to run in families. Where you grew up may also play a role. MS is more common in those who grew up in colder regions that are farther away from the equator.

What are the symptoms?

Symptoms depend on which parts of the brain and spinal cord are damaged and how bad the damage is. Early symptoms may include:

• Muscle problems. You may feel weak and stiff, and your limbs may feel heavy. You may drag your leg when you walk. You may drop things more than usual and be less coordinated.
• Visual problems. Your vision may be blurred or hazy. You may have eyeball pain (especially when you move your eyes), blindness, or double vision. Optic neuritis-sudden loss of vision that is often painful-is a fairly common first symptom.
• Sensory problems. You may feel tingling, a pins-and-needles sensation, or numbness. You may feel a band of tightness around your trunk or limbs or a feeling of electricity moving down your back and limbs.
• Balance problems. You may feel lightheaded or dizzy or feel like you're spinning.