- Relapsing-remitting multiple sclerosis
- Benign multiple sclerosis
- Primary progressive multiple sclerosis
The course of multiple sclerosis (MS) is unpredictable. The disease minimally affects some people while others experience a rapid progression to total disability. Most MS patients fit between these two extremes. Although every individual will experience a different combination of MS symptoms, there are a number of distinct patterns relating to the course of the disease.
Relapsing-remitting MS is the most common form of MS and typically occurs in young people. In this form of MS there are unpredictable relapses (exacerbations or attacks) during which new symptoms appear or existing symptoms become more severe. This can last for from days to months and there is partial or total recovery. The disease may be inactive for months or years. Approximately 85% of patients diagnosed with MS have relapsing-remitting multiple sclerosis.
After one or two attacks with complete recovery, this form of MS does not worsen with time and there is no permanent disability. Benign MS can only be identified when there is minimal disability ten to fifteen years after onset and initially would have been categorized as relapsing-remitting MS. Benign MS tends to be associated with less severe symptoms at onset, for example, sensory. Between 20% and 30% of patients diagnosed with MS have benign multiple sclerosis.
This form of MS is characterized by a lack of distinct attacks, but with slow onset and steadily worsening symptoms. There is an accumulation of deficits and disability that may level off at some point or continue over months and years. Approximately 10% of patients diagnosed with MS have primary progressive multiple sclerosis.
For some individuals who initially have relapsing-remitting MS, there is the development of progressive disability (i.e., nerve and muscle deterioration) later in the course of the disease often with superimposed relapses. Approximately 40% of patients diagnosed with MS have secondary progressive multiple sclerosis. Most patients suffer relapsing-remitting MS before it progresses to secondary progressive MS.
This is a rare form of MS in which the disease is progressive from its initial onset. Symptom flare-ups occur and deterioration continues in between relapses. Approximately 5% of patients diagnosed with MS have progressive relapsing multiple sclerosis.
