Experts recognize four types of multiple sclerosis based on how the disease develops and what course it takes. Some researchers also suggest using a staging system to clarify the complicated progression of the disease.
Types of MS
The four types of MS are:
They are distinguished by the frequency of symptoms and whether you experience progressive disability as part of your condition.
Clinically isolated syndrome
One way to think of clinically isolated syndrome is as a sort of "pre-MS." If you have a single neurological event that is consistent with symptoms of MS, it's considered clinically isolated until you have further episodes. If your CIS symptoms recur, it becomes a form of MS.
RRMS (relapsing-remitting MS)
RRMS is the most common type of multiple sclerosis, making up about 85% of all MS diagnoses. In relapsing-remitting MS, you experience bouts of MS symptoms (relapses or MS flare-ups) that can last days or weeks. In between bouts of symptoms, you'll have periods with little to no symptom activity (remission) that usually last 12 to 18 months.
SPMS (Secondary progressive MS)
Most people with RRMS will develop secondary progressive MS (SPMS). As RRMS progresses, relapses become longer and more frequent, and remission periods shorter.
Eventually, symptoms are present all (or almost all) the time, and the patient's general condition gradually declines. This is secondary progressive MS.
The disease course for SPMS is complex. Patients may have active or non-active SPMS, depending on whether they're currently experiencing symptoms. They may also have progressive or non-progressive periods, based on whether their overall state of disability is worsening or remaining stable.
PPMS (primary progressive MS)
Primary progressive MS is similar to SPMS. Like SPMS, it is marked by ongoing symptoms and a gradual increase in disability. However, there are a few important differences:
- Primary progressive MS is not preceded by RRMS.
- PPMS tends to progress more quickly and cause more significant disability.
- While SPMS often has a complicated course, including periods of remission and periods in which disability remains stable, PPMS is usually characterized by a steady decline in function without remission.
Stages of MS
The four types of MS are well-established, but it’s also valuable to classify the stages of MS. In this classification system, there are four stages of multiple sclerosis:
- Sub-clinical phase: Some people may have activity associated with MS before they ever experience symptoms or clinically isolated syndrome. This is called the "sub-clinical phase."
- High-risk phase: In the high-risk phase or early stage of MS, a person begins to have symptoms associated with multiple sclerosis.
- Relapsing-remitting phase: Symptoms are present and diagnosable. The relapse-remission cycle begins, and the patient has periods of symptoms alternating with asymptomatic periods.
- Progressive phase: In the final stage of MS, the disease worsens, and remission periods get shorter or disappear entirely. Not everyone with RRMS will experience this phase.
FAQs About the Different Types of MS
