Multiple Sclerosis

Specialty Area: Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease affecting the central nervous system (the brain and spinal cord). MS occurs when the immune system attacks nerve fibers and myelin sheathing in the brain and spinal cord. Myelin sheathing is a fatty substance that surrounds and insulates healthy nerve fibers to help transmit electrical messages along the nerves to various parts of the body. The abnormal immune attack causes inflammation which destroys nerve cell processes and myelin and interrupts these electrical messages. Because the messages don’t get through efficiently, both conscious and unconscious functions of the body can be impacted. The disease received its name because it causes many areas of the brain and spinal cord to become hardened (sclerosed) as scar tissues forms over damaged myelin. The course of the disease is unpredictable and varies from person to person.

Types of Multiple Sclerosis

There are several types of multiple sclerosis that reflect different courses of the illness:

Relapsing-Remitting MS: At the time of diagnosis, 90 percent of patients will have relapsing-remitting pattern of disease. This form of multiple sclerosis is characterized by the onset of the following symptoms over a period of hours to days:

• Numbness
• Tingling
• Blurred vision
• Unsteady gait

These symptoms tend to persist for days or weeks, and then disappear partially or completely on their own or with treatment. Patients may then remain symptom-free for weeks, months or even years. The periods of disease activity are called exacerbations or relapses. The periods without symptoms are called remissions. Without treatment, most people with MS will develop disease symptoms that will gradually worsen over time. In most cases, this will be without discernable relapses and remissions.

Secondary Progressive MS: If the condition progresses to a point where there are no discernable relapses and remissions, the diagnosis is secondary progressive MS.

Primary Progressive MS: About 10-15 percent of patients will have gradual worsening from the start of their MS disease. This is referred to as primary progressive MS.

Benign MS: Benign MS is a mild course where an individual will have mild disease after having MS for about 15 years. This occurs in about 5-10 percent of patients. There is no good way of predicting which patients will follow this course.

Who Gets Multiple Sclerosis?

• MS usually affects young adults, typically between the ages of fifteen and fifty.
• MS affects women more often than men.
• MS affects people of European descent more often than individuals of African or Asian ancestry.
• MS occurs more frequently in temperate zones than states near the equator.
• People with family members diagnosed with MS are at a slightly higher risk for developing the disease.

What Causes Multiple Sclerosis?

The exact cause of MS is unknown. It appears to be an autoimmune disease in which the immune system is stimulated to attack myelin in the central nervous system. The source of the initial stimulus has not been clearly identified. In certain people who inherit a predisposition to MS, the trigger may be infections (such as viruses) or other factors in the environment. Individuals may also have a genetic predisposition for developing the disease as people with family members diagnosed with MS are at a slightly higher risk.