Overview of the epidemiology, diagnosis, and disease progression associated with multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system that affects approximately 400,000 people in the United States. The etiology of MS is unknown, but it is likely the result of a complex interaction between genetic and environmental factors and the immune system. The clinical manifestations of MS are highly variable, but most patients initially experience a relapsing-remitting course. Patients accumulate disability as a result of incomplete recovery from acute exacerbations and/or gradual disease progression. This article briefly reviews the immunopathology of MS, the symptoms and natural course of the disease, and the recently revised MS diagnostic criteria.