Multiple sclerosis Health Article

Definition

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

Alternative Names

MS; Demyelinating disease

Causes, incidence, and risk factors

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

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)