There are 4 courses of the disease. In each case, the MS may be mild, moderate or severe.
- Relapsing – there are acute and unpredictable “exacerbations” (acute attacks, also called “flare-ups”). During this period symptoms get worse.
- Remitting – and then there are periods of full or partial recovery. Sometimes there is no recovery.
- The attacks may evolve over days or even weeks, and recovery can take weeks, or even months. In between the attacks there is calm, and symptoms do not worsen.
Primary-Progressive MS (PPMS): About 15% of patients have this type.
- There are no clear relapses or remissions.
- The progression of the disease is steady.
- It is the most common form of MS in those who develop the disease after 40 years of age.
Secondary-Progressive MS (SPMS):
- Starts off as a relapsing-remitting type of MS. Relapses and partial recoveries occur.
- However, in between cycles the disability does not go away.
- Eventually it becomes a progressive disease with no cycles.
- The progressive stage may start very early on, years, or even decades later.
Progressive-Relapsing MS (PRMS): The least common form.
- Symptoms worsen progressively, steadily
- There are acute attacks. Some recovery may follow, or may not.
- In the early stage, it seems the patient has primary progressive MS.