There are four main types of MS you should be aware of…
- Clinically isolated syndrome (CIS)
- Relapsing-Remitting MS (RRMS). This is the most common form of multiple sclerosis
- Secondary-Progressive MS (SPMS). In SPMS, symptoms worsen steadily over time, with or without the occurrence of relapses and remissions
- Primary-Progressive MS (PPMS) + Progressive-Relapsing MS (PRMS)
Clinically isolated syndrome (CIS) is one of the first episodes of neurologic symptoms. It generally lasts at least 24 hours and is caused by inflammation or demyelination i.e. loss of the myelin sheath that covers the nerve cells in the central nervous system (CNS). CIS is either monofocal or it could be multifocal:
- Monofocal episode: The patient experiences a single neurologic sign or symptom e.g. an attack of optic neuritis (that’s caused by a single lesion).
- Multifocal episode: The patient experiences more than one sign or symptom e.g. an attack of optic neuritis and numbness or tingling in the legs. Examination shows lesions in more than one place.
The clinically isolated syndrome (CIS) usually has no associated fever or infection and is followed by a complete or partial recovery.
In relapsing remitting MS (RRMS) patients have distinct attacks of symptoms which then fade away either partially or completely. Around 85 percent of people with MS are diagnosed with this type.
Note: A relapse is defined by the return of old symptoms or “the appearance of new symptoms” for a period of 24 hours or more – in the absence of a change in core body temperature or infection”.
Secondary Progressive MS (SPMS) is a stage of MS which comes after relapsing remitting MS in most cases. Specialists agree that secondary progressive MS is due to a “sustained and chronic build-up of disability and independent of any relapses”. Most people with relapsing remitting MS sadly will eventually develop secondary progressive MS.
Patients with primary progressive multiple sclerosis (PPMS) may first notice an issue with their walking and should either see a podiatrist or their doctor because of the leg weakness. This is rarest form however primary-progressive multiple sclerosis (PPMS) and is progressive from the start. Between 10 and 15 % of people with multiple sclerosis have this type of the disease. Unlike some other types of MS, there are no relapses or remissions.
In Progressive-Relapsing MS (PRMS) patients with distinct attacks of symptoms or relapses may or may not fully recover after these flares. Between relapses, the disease continues to get slowly worse . PRMS is the least common type of multiple sclerosis and only affects about 5% of people with the condition.
Note: Due to new guidelines defining the courses of MS published in 2014, Progressive-relapsing MS is no longer recognized as a separate course of MS due to overlap with other phenotypes and is now considered a part of primary progressive multiple sclerosis (PPMS).