To describe the natural history of a condition or disease. To describe the natural history of a condition or disease. To determine effectiveness or cost effectiveness of treatments/services and/or health care products. To measure or monitor safety and harm. To measure quality of care.
According to the NMSS, attacks or flare-ups of symptoms only qualify as exacerbations if: 1  they occur at least 30 days from an earlier flare-up. 2  symptoms last for 24 hours or longer.
An attack is followed by a time of recovery when you have no few or no symptoms, called remission. It can last weeks, months, or longer. The disease doesn't get worse during these breaks. After 10 to 20 years, RRMS usually changes to a different type of MS called secondary progressive multiple sclerosis. You wonât have relapses as often, but the disease gets gradually worse.