Multiple sclerosis is an autoimmune disease that affects the central nervous system. It disrupts the flow of information within the brain and between the brain and the body.
In people with multiple sclerosis (MS), the immune system attacks the central nervous system (CNS). As this continues to happen, symptoms get worse.
This article examines the different types of MS that can affect people and how their symptoms differ from each other.
There are four primary types, or disease courses, of MS.
By determining the specific type of MS a person has, doctors and researchers can focus their treatments and studies to produce better results.
The symptoms will appear and progress differently for each type, and some types involve long periods of remission, where symptoms disappear for a while.
The treatment and outlook may different, depending on the type.
Clinically isolated syndrome (CIS)
This is considered the first of the MS types. To be diagnosed with CIS, the neurologic symptoms that are caused by inflammation or the loss of myelin must last 24 hours. CIS may lead to other types of MS, but some people with CIS never progress.
Relapsing-remitting MS (RRMS)
This is the most common form of MS, and it accounts for approximately 80 to 85 percent of initial diagnoses of MS. RRMS involves clear episodes of inflammatory activity and well-defined attacks of new or recurrent neurologic symptoms. A person with RRMS will typically experience full or partial recovery between episodes.
With RRMS, the disease does not progress between relapses.
Primary-progressive MS (PPMS)
This type of MS is less common, accounting for about 10 to 15 percent of all cases. With PPMS, neurological function is impaired and gets worse as the disease progresses. People with PPMS do experience occasional plateaus in progression of the disease. There may be temporary, minor improvements to the symptoms during progression, but there are no relapses.
In the past, doctors used another category, progressive-relapsing MS (PRMS), to describe a form of MS that progresses from the beginning, with clear, acute relapses. However, this now comes under PPMS, as it follows a similar pattern.
Secondary-progressive MS (SPMS)
SPMS is normally seen as the next stage of the disease for people who already have RRMS. Around 50 percent of people with RRMS develop SPMS within 10 years, and nearly 90 percent do so after 25 years.
SPMS is similar to RRMS, but it may or may not involve occasional relapses, minor remissions, and plateaus.
Symptoms vary from person to person. Even if people have the same type of MS, the symptoms may present differently.
However, some symptoms are commonly associated with all types of MS.
These include:
- numbness and tingling
- fatigue
- weakness
- vision problems
- dizziness or coordination problems
While people with different types of MS may show similar symptoms, people with a particular type of the disease are likely to present specific symptoms.
For example, people with RRMS often experience tingling or numbness, episodes of visual loss in one or the other eye, urinary urgency, double vision, fatigue, weakness, and balance problems.
By contrast, PPMS typically causes less damage to the brain but has more effect on the spinal cord. People with this type of the disease may have problems walking, stiff legs, and trouble with balance.
Unlike with RRMS, these symptoms get progressively worse and there are no periods of relapse between them. SPMS features less distinct periods of relapse. A person with SPMS may have symptoms, such as bowel and bladder problems, weakness and coordination issues, stiff and tight legs, depression, fatigue, and problems with thinking.
Diagnosing MS
A person who has CIS may have similar symptoms as someone with MS, but they will have experienced the symptoms just once.
To be diagnosed with MS, a person must display evidence of damage in at least two separate areas of their CNS, such as the brain, the spinal cord, and the optic nerves. The problems must have occurred at least one month apart. Other conditions may have similar symptoms, so a doctor will need to rule out all other possible diagnoses.
The causes of MS remain unknown, but certain environmental and genetic factors appear to trigger the disease.
Risk factors that increase the chance of developing MS include:
- Age: Symptoms of relapsing types of MS normally appear in people between of 20 and 50 years. Progressive forms tend to occur about 10 years later than relapsing forms.
- Gender: In relapsing forms, women are 2 to 3 times more likely to be affected than men. However, the progressive forms occur equally in men and women.
- Family history: A person with a close relative who has MS is at higher risk of developing it.
- Location: MS is more common in people who live in a temperate climate.
- Infections: A number of viruses have been identified as possible causes of MS.
- Personal history of autoimmune disorders: People with thyroid disease, type 1 diabetes, and inflammatory bowel disease are at higher risk of developing MS.
It is difficult to predict how each type of MS will directly affect a person or which type has the best outlook.
RRMS tends to have a better outlook as there may be years between flare-ups and the disease does not progress between episodes.
However, people with RRMS usually develop SPMS, which is progressive and respond less well to medications, compared with other types.
Because of the way PPMS develops, they tend to be more debilitating. Symptoms will progress even during a relapse, which may or may not occur.
It can be helpful to connect with others who have a similar type of MS. MS Healthline is a free app that provides support through one-on-conversations and live group discussions with people who get it. Download the app for iPhone or Android.