MS ExplainedTypes of MS

Typically MS is a condition in which there is a period of relapses - also called attacks, episodes or exacerbations - which initially get better but are then followed by episodes where recovery is not complete, and eventually a period of slow progression with more persistent symptoms. However, this is a broad generalisation of a wide spectrum of experiences of MS.

The range of possible symptoms and the levels of severity of those symptoms mean the way MS affects one person may vary widely from someone else. Some people will live with the condition for many years with few or very minor symptoms. Others may experience no relapses at all but find that their symptoms and level of disability increase gradually from the onset of MS.

There are a number of 'types' of MS that are used to try to broadly group individuals in accordance with how the condition has developed. However, each type encompasses a wide range of experiences of MS and it is sometimes difficult to ascertain what type an individual has. It is also impossible to predict how an individual's MS will develop over time.

Relapsing remitting MS

The majority of people with MS are diagnosed with the relapsing/ remitting form. This means they will have periods when symptoms flare up - a relapse - followed by periods of good or complete recovery - a remission.

A relapse is the appearance of a new symptom or the reappearance of old symptoms that lasts more than 24 hours. A relapse often lasts for considerably longer than that and may persist for weeks or months. Many people also find that some of their symptoms will vary from day to day, being worse one day and better the next. This fluctuation is not classed as a relapse.

As a very broad average, people with relapsing remitting MS have one or two attacks a year, although for the individual, the number and frequency of relapses and the nature and severity of symptoms experienced are unpredictable.

Secondary progressive MS

Many people who are initially diagnosed with relapsing remitting MS find that over time the frequency of relapses decreases but disability increases. As this progressive phase follows a period of relapsing remitting MS it is known as secondary progressive MS.

As with relapsing remitting MS, people's experience of secondary progressive MS can vary widely. Some people find that the increase or progression of disability is very gradual, whilst for others it can occur more quickly.

Studies that have monitored people with MS over a long period of time suggest that after ten years, half those people who were diagnosed with relapsing remitting MS will have developed secondary progressive MS.

Primary progressive MS

About 10% of people with MS are diagnosed with a form in which disability increases from the outset, usually with the absence of distinct relapses. As this type is progressive from onset it is known as primary progressive MS . Unlike the relapsing and secondary progressive types where there is a proportion of two or three women for each man with MS, primary progressive MS is evenly distributed between the sexes.

Again, there is a variety of experience of primary progressive MS. Some people can have a persistent increase in disability whilst others may experience plateaux or a more gradual worsening of symptoms.

Benign MS

People with benign MS have very mild attacks separated by long periods with no symptoms. It is estimated that about 10% of people with MS have this form of the condition.

As the defining characteristic of benign MS is the long-term absence of symptoms, it can only be diagnosed retrospectively after ten or more years. The phrase is sometimes used inaccurately to describe a period of mild symptoms following diagnosis.

Rather than being a static form of MS, benign MS is probably a slower version of relapsing/ remitting MS in which the disease activity is not apparent. Over a long period of time, some people may find that their MS has started to display a clearer relapsing remitting pattern.