What Is Multiple Sclerosis?

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Jack Osbourne -- the son of legendary rocker Ozzy -- was looking for help with his suddenly blurred vision. Doctors found the cause of the problem – he has multiple sclerosis (MS). Though other celebrities like Montel Williams and Terri Garr have also publically spoken about their battles with the disease, Osbourne's recent revelation has folks wondering what, exactly, is MS?

What is MS?

MS is considered an autoimmune disease, meaning the immune system attacks healthy tissue in the body as though it were threat. MS is a chronic disease that strikes the central nervous system -- brain, spinal cord, optic nerve -- by attacking myelin, the sheath that surrounds and protects our nerve fibers. Once those fibers are damaged, nerve signals to and from the brain and spinal cord get disrupted, causing a multitude of symptoms, like tremors, loss of balance and muscle spasms.

Who has it?

According to the National Multiple Sclerosis Society, about 400,000 Americans are currently living with MS. Though the disease is two to three times more common in women, female patients tend to have a better prognosis than men.

MS is most commonly diagnosed between ages 20 and 40, and is more prevalent in Caucasians with northern European ancestry, though it can occur in any race or ethnic group.

Having a parent or sibling with MS ups the risk of developing the condition to 1 to 3 percent chance -- the risk without a family history is just .1 percent, according to the Mayo Clinic.

Symptoms and treatment

The course and progression of MS varies from person to person. About 85 percent of MS patients fall into the "relapsing-remitting" category, which is characterized by flare ups that cause a worsening of neurological function, followed by a partial or full recovery. In other cases, the progression can be slow (primary-progressive) or steadier (secondary-progressive and progressive-relapsing).

The symptoms of MS can run the gamut from mild to severe. They include numbness in one or more limbs; double or blurred vision; tingling or pain; tremors or lack of coordination; fatigue and dizziness. Other symptoms may be hearing loss, slurred speech, decreased concentration and painful muscle spasms.

In addition to drug therapy to slow the progression of MS and control its symptoms, people living with the condition may find additional relief by sleeping more, getting regular exercise, keeping the body's temperature normal, eating well and managing stress.