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 exacerbation (relapse, attack, or flare-up) of multiple sclerosis (MS) is indicated by a new sign orsymptom that lasts more than 24 hours, worsening of an old symptom that lasts more than 24 hours,or a repeated paroxysmal phenomenon (eg, bouts of vertigo or trigeminal neuralgia).