Multiple sclerosis

What is multiple sclerosis?

Multiple sclerosis is a chronic disease of the central nervous system that is characterized by inflammation of nerves in the brain and spinal cord. It also causes demyelination, a process of loss or destruction of the nerve’s myelin sheath, which functions to insulate the nerve and speed conduction of nerve signals.

How many people get multiple sclerosis?

Multiple sclerosis affects an estimated 2.5 million people worldwide and is one of the major causes of disability in adults under the age of 65. Approximately 330,000 people in the United States are afflicted with multiple sclerosis and about 200 new cases are diagnosed each week. Multiple sclerosis is typically diagnosed between the ages of 20 and 50, and the disease is two to three times as common in women as in men. Studies indicate that in addition to environmental components, genetic factors make certain individuals more susceptible than others, although there is no evidence that multiple sclerosis is directly inherited. It occurs more commonly among people with northern European ancestry, but people of other ethnic backgrounds are not immune.

What causes multiple sclerosis?

The pathogenesis of multiple sclerosis involves an autoimmune attack on the myelin sheath that surrounds and insulates nerves, resulting in areas of scarring. Although studies do indicate that genetic factors may make certain individuals more susceptible to the disease, multiple sclerosis is not directly inherited.

How is multiple sclerosis diagnosed?

The clinical symptoms of multiple sclerosis are caused by the disruption of nerve transmission and generally affect sensory and motor functions, including vision, coordination, strength, sensation, speech, swallowing, bladder control, sexuality and cognitive function. Although no single laboratory test is yet available to prove or rule out multiple sclerosis, magnetic resonance imaging can be very helpful in reaching a definitive diagnosis.

Is multiple sclerosis fatal?

The extent of neurological impairment in multiple sclerosis depends on the site and extent of the damage. Therefore, the nature and severity of specific symptoms vary greatly between individuals. The course of disease is difficult to predict and symptoms may relapse, progress or undergo spontaneous remission. Most people with multiple sclerosis can expect 95 percent of the normal life expectancy.

Multiple sclerosis typically takes one of four courses, each of which may be mild, moderate or severe.

• Up to 75 percent of patients begin with a relapse-remitting course of multiple sclerosis (RRMS), the most common form of the disease. RRMS is characterized by partial or total recovery after attacks (also called exacerbations, relapses or flares).
  
  
• Of the percentage of patients who begin with RRMS, more than half will develop secondary-progressive multiple sclerosis (SPMS) within 10 years, and 90 percent will develop it within 25 years. SPMS describes a relapsing-remitting course of disease, which later becomes steadily progressive. Attacks and partial recoveries may continue to occur.
  
  
• Primary-progressive multiple sclerosis (PPMS) describes a progressive course of disease from the onset, during which symptoms generally do not remit. Fifteen percent of people with multiple sclerosis are diagnosed with PPMS.
  
  
• The most rare form of the disease is progressive-relapsing multiple sclerosis (PRMS)—a progressive course of disease from the outset that is also characterized by obvious acute attacks. Less than 10 percent of people with multiple sclerosis appear to have PRMS at diagnosis.

How is multiple sclerosis treated?

Currently, there is no cure for multiple sclerosis, but the disease can be managed and treated, particularly using agents that modulate immune system activity or have anti-inflammatory effects. The National Multiple Sclerosis Society recommends treatment with one of the licensed “disease modifying” drugs as soon as possible after the diagnosis of a relapsing form (the most common kind) of multiple sclerosis. Interferon beta 1a (Avonex, Rebif), interferon beta 1b (Betaseron) and glatiramer acetate (Copaxone) are currently used in the management of multiple sclerosis and are believed to alter the course of disease, reduce future disability and improve quality of life. These drugs help to lessen the frequency and severity of multiple sclerosis attacks, reduce the accumulation of lesions (areas of damage) in the brain, and slow the progression of disability. Medications such as corticosteroids and muscle relaxants, as well as physical therapy and counseling, may also be used to relieve symptoms.

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