ABSTRACT
Multiple sclerosis is an inflammatory, demyelinating condition of the central nervous system. It occurs throughout the world, but is particularly common in North America, Australasia and northern Europe, affecting at least 500 000 people in the United States and 80 000 people in the United Kingdom, where it has a prevalence of approximately one in 800. Multiple sclerosis usually presents with an attack of neurological dysfunction which builds up over days and then improves partially or fully over weeks or months. Remitting disorders include neurosarcoidosis, systemic lupus erythematosus and Behcet’s disease, although the remissions in the conditions are usually incomplete. The pathological changes which occur in the normal and lesional brain tissue give rise to functional effects which are transient in some cases and permanent in others. The balance between these processes, and the degree to which the pathological tissue is capable of self-repair, can explain some of the clinical manifestations of relapse, remission and permanent disability.
