The incidence is greater in urban dwellers and among affluent socioeconomic groups. The cause of MS is unknown but there is growing evidence that it may result from a combination of genetic, environmental and immunologic factors. In general, the incidence of MS appears to be increasing. MS is more frequent in areas that are distant from the equator. It is likely that a viral infection initiates the MS process, followed by an autoimmune response in a genetically predisposed host.
Symptoms develop as nerve conduction slows and then fails completely.
The typical attack is relatively sudden in onset, persists for 3 to 12 weeks then clears. Memory and attention deficits also occur. Classically, MS is characterized by periods of remissions and exacerbations that occur at unpredictable intervals over a period of several years with initial episodes tending to resolve completely. It is the accumulated burden of multiple attacks that causes persistent symptoms. Treatment is directed against the underlying disease process and toward alleviating symptoms.