Multiple sclerosis is a disease of the central nervous system, brain, optic nerve, and spinal cord. In multiple sclerosis, the protective covering known as myelin that protects the nerves becomes damaged. Damaged myelin and damaged nerves disrupt the smooth flow of nerve impulses within the brain and between the brain, spinal cord, and body, causing the symptoms of multiple sclerosis. The areas of inflammation or damage that occur in the central nervous system are known as lesions or plaques.
Approximately 400,000 individuals have multiple sclerosis in the United States and 2.5 million worldwide. Most people are diagnosed with multiple sclerosis between the ages of 15 and 50. Women are more likely than men to develop the relapsing form of multiple sclerosis. Caucasians have a higher incidence of multiple sclerosis than those of African heritage. African Americans may experience more problems with vision and mobility. People living further from the Equator have a higher risk of multiple sclerosis.
The relapsing form of multiple sclerosis is the most common type. Relapses are referred to as exacerbations, attacks, or flares. Relapses occur when inflammation occurs along the nerves disrupting the myelin, causing new symptoms or a temporary worsening or recurrence of symptoms. Treatments are available to reduce the severity and duration of a relapse.
Lesions of multiple sclerosis may be viewed on an MRI scan of the brain or spinal cord. By evaluating the size and location of lesions, areas of inflammation, and myelin or nerve damage, disease activity within the nervous system may be measured. Other tests that might be performed include lumbar puncture and evoked potential studies, which measure the speed of the brain’s response to visual, auditory, or sensory stimuli.
Multiple sclerosis symptoms are variable and unpredictable. No two people have exactly the same symptoms, and each person’s symptoms can change or fluctuate over time. One person might experience only one or two of the possible symptoms while another person may experience many more.
Extensive research is currently being undertaken to better understand the function of the immune system.
- The cause of multiple sclerosis is still unknown. A combination of factors appears to be involved. Scientists currently believe the disease is triggered by an as yet unidentified environmental factor(s) in a person who is genetically predisposed to respond.
- Numbness and tingling
- Dizziness and vertigo
- Walking and gait difficulties
- Visual problems
- Bladder problems
- Bowel problems
- Cognitive changes
- Sexual problems
- Emotional changes
- Speech problems
- Swallowing problems
- Hearing loss
- Long-term treatments are only available for individuals with relapsing forms of the disease
- Disease-modifying therapies may reduce the number and severity of flares or exacerbations, delay disease progression, reduce the number of active lesions, and potentially decrease disability progression
- Treatments are being explored for neuroprotection (protecting the nerves) and remyelination (regenerating the protective nerve covering).