It has a higher incidence in northern Europe, northern United States, southern Australia, and New Zealand than in other areas of the world. There seems to be a familial tendency toward the disorder, with higher incidence in certain family groups than in the general population. An increase in the number of immune cells in the body of a person with MS indicates that there may be a type of immune response that triggers the disorder. The most frequent theories about the cause of multiple sclerosis include a virus-type organism, an abnormality of the genes responsible for control of the immune system, or a combination of both factors. They may last days to months, then reduce or disappear, then recur periodically.
Fever can trigger or worsen attacks, as can hot baths, sun exposure, and stress .
This may include decreased or abnormal sensation, decreased ability to move a part of the body, speech or vision changes, or other loss of neurologic functions. The type of neurologic deficit may indicate, to some extent, the location of the damage to the nerves. Treatment is aimed at controlling symptoms and maintaining function to give the maximum quality of life. Medications vary depending on the symptoms that occur. Baclofen, dantrolene, diazepam or other anti-spasmodic medications may be used to reduce muscle spasticity .