Multiple sclerosis (MS) is a chronic disease that affects the central nervous system. It affects more than 2 million people worldwide and is 3 times more common in women than in men.
A person's risk of developing MS is increased if they have a close relative with the condition.
The cause of MS is not known, but theories include that it is an autoimmune disease; that it is caused by genetic or environmental factors (it is more common the further away from the equator you live); and that it is caused by a virus.
There is currently no known cure for MS although there are treatment options. MS affects different people in different ways, and treatment often involves symptom management.
Types of MS
Relapsing-remitting MS (RRMS). This is the most common form of MS and about 3 in every 4 people with MS begin with a relapsing-remitting stage.
With RRMS, new symptoms appear or existing symptoms worsen over a period of days, weeks or even months, followed by a partial or complete recovery, which is then followed by another relapse. For some people, these relapses get worse and the disability stays. Their health gradually declines. This is known as secondary progressive MS (see below).
Primary progressive MS (PPMS). One or 2 people in every 10 with MS are diagnosed with PPMS. These people usually find that their symptoms become gradually worse, with no separate attacks.
Secondary progressive MS (SPMS). Most people with RRMS will eventually experience SPMS. In this form, disability generally worsens slowly, independent of any relapses.
How is MS diagnosed?
A range of tests can be used to diagnose MS, including an MRI to detect lesions in the central nervous system, a physical examination to check reflexes and responses, blood tests, lumbar punctures and other types of tests to measure nerve activity.
Sometimes it can take years to reach a diagnosis because there is no single test for MS. A person will be diagnosed with MS if there is evidence of lesions in different parts of the central nervous system, at different times, with no other explanation than MS.
For more information about MS, including about symptoms, the different types of MS, medications and treatments, and how to talk to children about MS, see the MS Australia website.
Last reviewed: November 2016