What You Need to Know About Multiple Sclerosis
During a multiple sclerosis attack, inflammation occurs in random areas of the white matter of the central nervous system. These areas of inflammation are called plaques. This process is followed by destruction of myelin, the fatty covering that insulates nerve cell fibers in the brain and spinal cord. Myelin facilitates the smooth, high-speed transmission of electrochemical messages between the brain, the spinal cord, and the rest of the body. When myelin is damaged, transmission of messages through that part of the nervous system may be slowed or blocked completely, leading to diminished or lost function.
The name "multiple sclerosis" signifies both the number (multiple) and condition (sclerosis, from the Greek term for scarring or hardening) of the demyelinated areas in the central nervous system.
The vast majority of patients with multiple sclerosis are mildly affected, but in the worst cases, multiple sclerosis can render a person unable to write, speak, or walk. A physician can diagnose multiple sclerosis in some patients soon after the illness begins. In others, however, doctors may not be able to identify the cause of the symptoms right away, leading to years of uncertainty and multiple diagnoses, punctuated by baffling symptoms that mysteriously come and go.
(Click Multiple Sclerosis Diagnosis for a closer look at how this condition is diagnosed.)
Most people experience their first symptoms of multiple sclerosis between the ages of 20 and 40. And although scientists have documented cases of multiple sclerosis in young children and elderly adults, symptoms rarely begin before age 15 or after age 60.
No one knows exactly how many people have multiple sclerosis. It is believed that there are currently about 250,000 to 350,000 people in the United States who have been diagnosed with multiple sclerosis. This estimate suggests that approximately 200 new cases of multiple sclerosis are diagnosed each week.
Whites are more than twice as likely as other races to develop multiple sclerosis. In general, women are affected at almost twice the rate of men; however, among patients who develop the symptoms of multiple sclerosis at a later age, the gender ratio is more balanced.
Multiple sclerosis is five times more prevalent in temperate climates -- such as those found in the northern United States, Canada, and Europe -- than in tropical regions. Furthermore, the age of 15 seems to be significant in terms of risk for developing the disease: Some studies indicate that a person moving from a high-risk (temperate) to a low-risk (tropical) area before the age of 15 tends to adopt the risk (in this case, low) of the new area and vice versa. Other studies suggest that people moving after age 15 maintain the risk of the area where they grew up.
(Click Multiple Sclerosis Statistics for more information.)