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.
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.
- numbness and tingling
- 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.
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 most common treatment is medication.
New medications, known as disease modifying therapies (DMTs), are proving successful in slowing disease progression and keeping the condition stable.
A doctor may suggest using a DMT in the early stages of MS, as they can help to stop symptoms from getting worse.
The National Muliple Sclerosis Society list a number of DMTs that the FDA has approved for modifying the course of MS.
Clinical trials have shown that DMTs can:
- decrease the number of relapses
- slow the onset of disability
- limit new disease activity
Treatment with a DMT is long-term. It is important to understand the need to commit to regular and ongoing treatment, in order for it to be effective.
DMTs, like all medications, can have some side effects. The doctor will speak to the individual about the options available and the risks involved. They will help the individual to choose the best option.
Common risks of DMTs include:
- liver problems
- an increased risk of infection
- possible problems during pregnancy
People should also speak to a doctor before seeking to become pregnant or as soon as they find they are pregnant, as the drug may affect the unborn child.
The risks vary between medications. It is important to talk to a doctor before using any of these drugs and to monitor for any unwanted changes while using them. If a person wishes to stop taking a DMT, they should speak to their doctor before doing so.
Medication regimens vary greatly between people. For some DMTs, the doctor will give the drug by needle as an injection or an infusion, but people can take others by mouth as a tablet. Doses may be daily, weekly, or monthly.
The medication will also depend on the type of MS a person has.
Examples of this type of medication include:
- alemtuzumab (Campath)
- fingolimod (Gilenya)
- natalizumab (Tysabri)
- mitoxantrone (no brand name in the United States)
- ocrelizumab (Ocrevus)
In the past, few options were available for people with MS, but now the range of drugs is growing. If a person has been taking an older DMT, such as mitoxantrone, a doctor may recommend switching to newer drug, as the newer ones may have fewer risks.
Managing relapses and other symptoms
DMTs are important for slowing the progression of MS, but relapses can still occur.
A doctor may prescribe injectable or oral corticosteroids to help manage relapses when they occur.
Other treatments can help to treat specific symptoms such as bladder problems, mood changes, fatigue, itching, and pain.
Some researchers have suggested that a lack of vitamin D may be a possible factor in the progression of MS.
Doctors may recommend that people with PPMS take exercise, ensure they eat a healthful diet, and get some physical therapy.
People with MS may find that these alternative treatments can lessen symptoms and improve quality of life.
When to see a doctor
Anyone experiencing any of the symptoms of MS should seek medical advice.
An early diagnosis of MS can lead to a more effective management of symptoms. Catching the disease early may even slow the course of the disease.
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.
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.