It is generally accepted that there are 3 main subtypes of MS;
The majority of people, around 75% of those diagnosed with MS, are classified as having RRMS, this is where the disease comes in waves or relapses where symptoms will manifest and after the relapse they will either partially resolve or fully resolve over a period of weeks. This is then followed by a period of remission.
If left untreated about 80% of those diagnosed with RRMS will go on to develop what we call secondary progressive MS, but in most cases RRMS will be treated. In SPMS, the disease begins to worsen more steadily, with or without occasional attacks, and without remissions.
And for a small minority, about 10 to 15% will be diagnosed with PPMS where they will have characterized by steadily worsening neurologic function from the beginning. The rate of progression may vary over time with or without occasional attacks, slight remissions.
Now it is important to note while these might appear to be distinct subgroups, it is probably better to consider MS as a single disease which manifests in a spectrum extending from relapsing MS through progressive forms, and sometimes this can be subdivided into additional subtypes like progressive relapsing MS.
Our MS in a Minute videos were created to provide fast and factual definitions of commonly used terms in MS.