Regionally, the median estimated prevalence of MS is greatest in Europe (80 per 100 000), followed by the Eastern Mediterranean (14.9), the Americas (8.3), the Western Pacific (5), South-East Asia (2.8) and Africa (0.3). Regionally, the median estimated incidence of MS is greatest in Europe (3.8 per 100 000), followed by the Eastern Mediterranean (2), the Americas (1.5) and the Western Pacific.
The Multiple Sclerosis is classified into 4 forms:
- Relapsing-Remitting MS (RRMS): the most common form of multiple sclerosis (75-85%). It is cyclic form characterized by relapses with stable neurologic disability between episodes.
- Secondary-Progressive MS (SPMS): The majority of patients after an initial remitting phase evolve within a variable period of 5 to 20 years through a secondary progressive form.
- Primary-Progressive MS (PPMS). This type of MS is not very common, occurring in about 10% of MS patients, more frequent for patients after 40. PPMS is a progressive course from disease onset characterized by slowly worsening symptoms from the beginning, with no relapses or remissions.
- Progressive-Relapsing MS (PRMS). A rare form of MS (5%), PRMS is characterized by a steadily worsening disease state from the beginning, with acute relapses but no remissions, with or without recovery.