Multiple sclerosis (MS) affects nerves in the brain and spinal cord, causing a wide range of symptoms including problems with muscle movement, balance and vision.
Each nerve fibre in the brain and spinal cord is surrounded by a layer of protein called myelin, which protects the nerve and helps electrical signals from the brain travel to the rest of the body. In MS, the myelin becomes damaged.
This disrupts the transfer of these nerve signals, causing a wide range of potential symptoms, such as:
- loss of vision – usually only in one eye
- spasticity – muscle stiffness that can lead to uncontrolled muscle movements
- ataxia – difficulties with balance and co-ordination
- fatigue – feeling very tired during the day
Read more about the symptoms of multiple sclerosis.
Types of multiple sclerosis
Around eight out of 10 people with MS are diagnosed with the relapsing remitting type of MS.
Someone with relapsing remitting MS will have flare-ups of symptoms, known as relapses. These can last from a few days to a few months.
These will be followed by periods where symptoms are mild or disappear altogether. This is known as remission and can last for days, weeks or sometimes months.
Usually after around 15 years, around half of people with relapsing remitting MS will go on to develop secondary progressive MS.
In secondary progressive MS, symptoms gradually worsen over time. Some people may still have relapses, but without full recovery from symptoms.
The least common form of MS is primary progressive MS. In this type, symptoms gradually get worse over time and there are no periods of remission.
There is currently no cure for MS but there are a number of treatments that can help.
Relapsing remitting MS can be treated with disease-modifying drugs. These are designed to reduce the number of relapses someone has. They may also be able to slow the progression of MS. But they are not suitable for all people with MS.
Some of these drugs can also be used for treating secondary progressive MS, if someone is still experiencing relapses.
At the moment, there is no treatment that can slow the progress of primary progressive MS.
There are also a wide range of treatments, including physiotherapy, that can help relieve symptoms and make day-to-day living easier. Steroids can also be used to speed up recovery from relapses.
Read more about the treatment of multiple sclerosis.
MS is known as an autoimmune condition. This is where something goes wrong with the immune system (the body’s defence against infection) and it mistakenly attacks healthy body tissue – in this case, the myelin covering of nerves.
This can cause multiple sections of the brain and spinal column to become damaged and hardened (sclerosis), which can disrupt the nerve signals passing through these areas.
Exactly what causes the immune system to act in this way is unclear, but most experts think a combination of genetic and environmental factors are involved.
Read more about the possible risk factors and causes of multiple sclerosis.
Who is affected
It is estimated that there are currently around 100,000 people with MS in the UK.
MS is most commonly diagnosed in people aged 20-40, although it can happen at any age. Children can also get MS, although this is rare.
For reasons that are unclear, MS is three times as common in women than men, and more common in white people than black and Asian people.
MS can be a challenging and frustrating condition to live with but new treatments over the past 20 years have considerably improved the quality of life of people with the condition.
MS is not fatal, but some complications that can arise from severe MS, such as pneumonia, can be.
As a result, the average life expectancy for people with MS is around five to 10 years lower than the population at large. This gap appears to be getting smaller, perhaps because of improved medical care.