Multiple sclerosis is an autoimmune disease that affects the brain and spinal cord (central nervous system).

Multiple sclerosis (MS) affects woman more than men. The disorder most commonly begins 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.

MS is a progressive disease, meaning the nerve damage (neurodegeneration) gets worse over time. How quickly MS gets worse varies from person to person.

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 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.

MS is more likely to occur in northern Europe, the northern United States, southern Australia, and New Zealand than in other areas. 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 with a higher incidence rate for MS have a 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.

Muscle symptoms:

• Loss of balance
• Numbness or abnormal sensation in any area
• Pain because of muscle spasms
• Pain in the arms or legs
• Problems moving arms or legs
• Problems walking
• Problems with coordination and making small movements
• Slurred or difficult-to-understand speech
• Tremor in one or more arms or legs
• Uncontrollable spasm of muscle groups (muscle spasticity)
• Weakness in one or more arms or legs

Eye symptoms:

• Double vision
• Eye discomfort
• Uncontrollable rapid eye movements
• Vision loss (usually affects one eye at a time)

Other brain and nerve symptoms:

• Decreased attention span
• Decreased judgment
• Decreased memory
• Depression or feelings of sadness
• Dizziness and balance problems
• Facial pain
• Hearing loss
• Fatigue

Bowel and bladder symptoms:

• Constipation
• Difficulty beginning urinating
• Frequent need to urinate
• Stool leakage
• Strong urge to urinate
• Urine leakage (incontinence)

Symptoms of MS may mimic those of many other nervous system disorders. The disease is diagnosed by ruling out other conditions.

People who have a form of MS called relapsing-remitting may have a history of at least two attacks, separated by a period of reduced or no symptoms.

The health care provider may suspect MS if there are decreases in the function of two different parts of the central nervous system (such as abnormal reflexes) at two different times.

A neurological exam may show reduced nerve function in one area of the body, or spread over many parts of the body. This may include:

• Abnormal nerve reflexes
• Decreased ability to move a part of the body
• Decreased or abnormal sensation
• Other loss of nervous system functions

An eye examination may show:

• Abnormal pupil responses
• Changes in the visual fields or eye movements
• Decreased visual acuity
• Problems with the inside parts of the eye
• Rapid eye movements triggered when the eye moves

Tests to diagnose multiple sclerosis include:

• Cerebrospinal fluid tests, including CSF oligoclonal banding
• Head MRI scan
• Lumbar puncture (spinal tap)
• Nerve function study (evoked potential test)
• Spine MRI

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 may include:

• Immune modulators to help control the immune system, including interferons (Avonex, Betaseron, or Rebif), monoclonal antibodies (Tysabri), glatiramer acetate (Copaxone), mitoxantrone (Novantrone), methotrexate, azathioprine (Imuran), cyclophosphamide (Cytoxan), and natalizumab (Tysabri)
• Steroids may be used to decrease the severity of attacks

Medications to control symptoms may include:

• Medicines to reduce muscle spasms such as Lioresal (Baclofen), tizanidine (Zanaflex), or a benzodiazepine
• Cholinergic medications to reduce urinary problems
• Antidepressants for mood or behavior symptoms
• Amantadine for fatigue

The following may help MS patients:

• Physical therapy, speech therapy, occupational therapy, and support groups
• Assistive devices, such as wheelchairs, bed lifts, shower chairs, walkers, and wall bars
• A planned exercise program early in the course of the disorder
• A healthy lifestyle, with good nutrition and enough rest and relaxation
• Avoiding fatigue, stress, temperature extremes, and illness

For additional information, see multiple sclerosis resources.

The outcome varies, and is unpredictable. 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:

• Females
• 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. As the disorder gets worse, there is greater loss of function with less improvement between attacks.

• Depression
• Difficulty swallowing
• Difficulty thinking
• Less and less ability to care for self
• Need for indwelling catheter
• Osteoporosis or thinning of the bones
• Pressure sores
• Side effects of medications used to treat the disorder
• Urinary tract infections

Call your health care provider if:

• You develop any symptoms of MS
• Symptoms get worse, even with treatment
• The condition deteriorates to the point where home care is no longer possible

Calabresi P. Multiple sclerosis and demyelinating conditions of the central nervous system. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 436.

Gray OM, McDonnell GV, Forbes RB. A systematic review of oral methotrexate for multiple sclerosis. Mult Scler. 2006;12:507-510.

Farinotti M, Simi S, Di Pietrantonj C, McDowell N, Brait L, Lupo D, Filippini G. Dietary interventions for multiple sclerosis. Cochrane Database Syst Rev. 2007 Jan 24;(1):CD004192.

Miller DH, Leary SM. Primary-progressive multiple sclerosis. Lancet Neurol. 2007;6:903-912.