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
Types of multiple sclerosis
Relapsing remitting MS
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.
Secondary progressive MS
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.
Primary progressive MS
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.
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.
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.
Symptoms of multiple sclerosis
The central nervous system (brain and spinal cord) controls all of your body's actions. When MS damages the myelin coating around the nerve fibres that carry messages to and from your brain, symptoms can occur in any part of your body.
There are many different symptoms of MS and they affect each person differently. Some of the most common symptoms include:
extreme tiredness (fatigue)
numbness and tingling
blurring of vision
problems with mobility and balance
muscle weakness and tightness
Most people with MS only have a few of these symptoms and it is unlikely someone would develop all possible symptoms.
The symptoms are unpredictable. Some people's MS symptoms develop and increase steadily over time, while for others, they come and go periodically.
These periods when symptoms get worse are known as relapses. Periods when symptoms improve or disappear are known as remissions.
In around one in five cases of MS, the first noticeable symptom is problems with one of your eyes. You may experience:
some loss of vision in the affected eye – this can range from mild to severe (total loss of vision occurs in one in 35 cases)
eye pain; usually made worse when moving the eye
flashes of light when moving the eye
These symptoms are the result of optic neuritis, which is inflammation (swelling) of the optic nerve that transmits visual information to the brain. This normally only affects one eye.
Other visual problems that can occur in MS include:
eye pain in both eyes
involuntary eye movements (usually from side to side), known as nystagmus
Abnormal sensations can also be a common initial symptom of MS. This can take the form of numbness or tingling in different parts of your body.
Muscles in your arms and legs may also feel unusually weak.
Muscle spasms and spasticity
If messages between your brain and muscles are disrupted, this can cause problems with muscle movements. It can cause muscles to contract tightly and painfully (spasm) or your muscles may also become stiff and resistant to movement, known as spasticity.
Around half of people with MS experience pain, which can take two forms:
Neuropathic pain – caused by damage to the nerve fibres in the brain and spinal cord. It can be a stabbing pain, extreme skin sensitivity, or a burning sensation.
Musculoskeletal pain – this is not caused directly by MS, but can occur if there is excess pressure on muscles or joints as a result of spasms and spasticity.
MS can affect balance and co-ordination. It can make walking and moving around difficult, particularly if you also have muscle weakness and spasticity. You may experience:
ataxia – difficulty with co-ordination
tremor – shaking of the limbs, which is rare, but can be severe
dizziness and vertigo can happen late on and can make you feel as if your surroundings are spinning
Extreme tiredness (fatigue)
Feeling extremely tired (fatigue) is a common symptom of MS that many people describe as one of the most troublesome.
It is estimated that as many as nine out of 10 people with MS will experience episodes of fatigue.
People with MS have reported feeling an overwhelming sense of weariness where even the most simple physical or mental activity seems to be a tremendous struggle to carry out.
Fatigue may be worse in hot weather, after exercising, or during illness.
Problems with thinking, learning and planning
Around half of people with MS have problems with thinking, learning and planning (known as cognitive dysfunction). They may experience:
problems understanding and using language
a shortened attention span
problems learning and remembering new things (long-term memory is usually unaffected)
problems understanding and processing visual information, such as reading a map
difficulty with planning and problem solving – people often report that they know what they want to do, but can’t grasp the method of how to do it
problems with reasoning, such as mathematical laws or solving puzzles
Mental health issues
Around half of all people with MS experience at least one episode of depression at some point in their life.
It is unclear whether the depression arises from the damage to the brain caused by MS, or due to the stress of having to live with a long-term condition, or both.
Anxiety can also be a problem for people with MS, possibly due to the unpredictable nature of the condition.
Some people with MS can sometimes experience rapid and severe mood swings, suddenly bursting into tears, laughing or shouting angrily for no apparent reason.
MS can have an effect on sexual function.
Men with MS often find it hard to obtain or maintain an erection (erectile dysfunction). They may also find it takes a lot longer to ejaculate when having sex or masturbating, and may even lose the ability to ejaculate altogether.
For women, problems include difficulty reaching orgasm as well as decreased vaginal lubrication and sensation.
Both men and women with MS may find they are less interested in sex than they were before. This could be directly related to the MS, or it could be the result of living with the condition.
Bladder problems are common in MS.
They may include:
difficulty emptying the bladder completely
having to urinate more frequently
having a sudden, urgent need to urinate which can lead to unintentionally passing urine (urge incontinence)
having to get up frequently during the night to pass urine (nocturia)
Many people with MS have problems with their bowel.
Constipation is the most common problem, affecting around half of people with MS. They may pass stools much less frequently than normal, and find this difficult.
Bowel incontinence is less common but is often linked to constipation. If a stool becomes stuck, it can irritate the wall of the bowel, causing it to produce more fluid and mucus that can leak out of the anus (back passage).
Speech and swallowing difficulties
Around a third of people with MS experience difficulty chewing or swallowing (dysphagia) at some point. In some cases, speech may also become slurred, or difficult to understand.
However, for most people with MS, speech and swallowing symptoms are mild and only last for a few minutes at a time. They are often at their worst during a relapse.
In a small number of cases a person has a small number of relapses followed by a complete recovery. This is known as benign MS.
A diagnosis of benign MS can only be made with confidence if you have been largely free of symptoms for more than 20 years.
Causes of multiple sclerosis
The exact reason why someone develops multiple sclerosis (MS) is not known. What is known so far suggests it is caused by a combination of environmental and genetic factors.
MS is an autoimmune condition. This means your immune system mistakes the myelin for a foreign substance and attacks it. The myelin becomes inflamed in small patches (called plaques or lesions), which can be seen on an MRI scan.
This can disrupt the messages travelling along nerve fibres. It can slow them down, jumble them, send them down a different nerve fibre, or stop them from getting through completely.
When the inflammation goes away, it can leave behind scarring of the myelin sheath (known as sclerosis). These attacks can eventually start to destroy the myelin sheath (demyelination), which can damage the underlying nerve fibre.
Why do people develop multiple sclerosis?
It is not understood what causes the immune system to attack myelin, although there are several theories. Most experts agree that MS is probably caused by a combination of genetic and environmental factors. This means it's partly caused by genes you inherit from your parents and partly caused by outside factors that may trigger the condition.
MS is not defined as a genetic condition because there is no single gene that causes it. It's not directly inherited, although research has shown people who are related to someone with MS are more likely to develop it.
Researchers have found that if one twin develops MS then the second twin has around a one in four chance of also developing MS.
The chance of a brother, sister or child of a person with MS also developing MS themselves is less than one in 30.
It's possible that different combinations of genes make developing MS more likely, and research into this is continuing. However, genetic theories cannot explain the wide variation in occurrences of MS throughout the world.
Sunlight and vitamin D
Research into MS around the world has shown that it's more likely to occur in countries far from the equator. For example, MS is relatively common in the UK, North America and Scandinavia, but rare in Malaysia or Ecuador.
It’s possible that people living further from the equator are exposed to less sunlight and, therefore, have less vitamin D in their bodies. Some studies have found a link between lower levels of vitamin D and incidence of MS.
Some researchers have suggested that vitamin D supplements may reduce the risk of MS. However, this has not been proven.
Smoking is another factor that appears to increase someone’s risk of developing MS. It is not yet clear exactly why this is, although one theory is that the chemicals in the cigarette smoke affect the immune system.
Another theory is that a virus may be involved in the development of MS. The Epstein-Barr virus (EBV) has been the subject of most of the current studies.
MS is thought to be an autoimmune condition, where the body's own immune system attacks healthy tissue. One possible explanation is that a virus might cause a strong response from the immune system, which leads it to target healthy parts as well as the virus.
More research is needed to further understand how EBV may increase the risk of developing MS.
Diagnosing multiple sclerosis
If you have unexplained symptoms that are similar to those of multiple sclerosis (MS), see your GP. If your GP suspects MS, they will ask you for a detailed medical history, including past signs and symptoms as well as the current state of your health.
Your GP can refer you to a neurologist (a specialist in conditions of the central nervous system).
If your GP suspects MS, you should see a neurologist within six weeks.
Diagnosing MS is complicated because no single laboratory test can positively diagnose it.
Several conditions have symptoms similar to those of MS, so your neurologist may rule them out first.
It may also not be possible to confirm a diagnosis if you have had only one ‘attack’ of MS-like symptoms. A diagnosis can usually only be made with confidence once there is evidence of at least two separate attacks.
To confirm MS, your neurologist may carry out a number of tests.
Your neurologist will look for changes or weakness in your eye movements, leg or hand co-ordination, balance, speech and reflexes. This will show whether your nerve pathways are damaged.
Magnetic resonance imaging (MRI) scan
An MRI scan creates a detailed image of your brain and spinal cord.
MRI scans can show whether there is any damage or scarring of the myelin in your central nervous system. The results of the MRI scan confirm a diagnosis in over nine out of 10 people who have MS.
The procedure is painless and usually takes between 10 and 30 minutes. A standard MRI scanner is like a giant tube or tunnel. You may feel claustrophobic when going into the tunnel and the machine is noisy.
Tell your neurologist if you have any concerns about this experience.
Evoked potentials test
An evoked potentials test involves placing small electrodes on your head. These monitor how your brain waves respond to what you see and hear. It is painless and can show whether it takes your brain longer than normal to receive messages.
A lumbar puncture is also sometimes called a spinal tap. A sample of your cerebrospinal fluid (the fluid that surrounds your brain and spinal cord) is taken using a needle inserted into the area around your spinal cord.
This is done under local anaesthetic, which means that you will be awake, but the area the needle goes into will be numbed. The sample is tested for antibodies, the presence of which means that your immune system has been fighting a disease in your central nervous system.
A lumbar puncture is usually only needed if other tests for MS are inconclusive.
Blood tests are usually performed to rule out other causes of your symptoms, such as vitamin deficiencies. In addition, antibody tests may be required, for example to rule out a very similar condition calledneuromyelitis optica (NMO).
Diagnosing the different types of multiple sclerosis
Once a diagnosis of MS has been made, your neurologist may be able to identify which type of MS you have.
However, this often only becomes clear over time as the symptoms of MS are so varied and unpredictable.
A diagnosis of relapsing remitting multiple sclerosis (RRMS) may be made if:
you have two relapses of your symptoms more than 30 days apart
you have one relapse and an MRI scan shows new myelin damage or scarring three months later
A diagnosis of secondary progressive multiple sclerosis (SPMS) may be made if:
you have had relapses of your symptoms in the past
you have become steadily more disabled for at least six months, with or without relapses
MS never starts out as secondary progressive. However, it is possible for someone to be told they have this type if they have had unexplained symptoms for some time.
A diagnosis of primary progressive multiple sclerosis (PPMS) may be made if you have had no previous relapses of your symptoms, and:
you have become steadily more disabled for at least one year
an MRI scan shows damage and scarring to myelin
a lumbar puncture shows antibodies in the fluid surrounding your brain and spinal cord
In rare cases, some people with primary progressive multiple sclerosis can have relapses. This can make it even harder to clearly identify what type of MS they have.
Treating multiple sclerosis
The National Institute for Health and Care Excellence (NICE) has published a clinical guideline for MS.
The guideline provides comprehensive evidence-based information on the benefits and limitations of various methods of diagnosing, treating and caring for people with MS. This helps health professionals and patients decide on the most appropriate treatment.
The NICE guideline states that if you have MS, you should have access to a specialist neurological rehabilitation team. This is because MS is a complex disorder that can impact on many aspects of your life so you will need to receive treatments from a number of different health professionals working together.
Members of your care team may include:
a neurologist (a specialist in treating conditions that affect the nervous system)
a speech and language therapist
an occupational therapist
a continence adviser
a social worker
a specialist MS nurse who will often serve as a point of contact
You should have a way of contacting your team, for example by calling an MS specialist nurse. You should have someone who gives you reliable information about MS and its symptoms and treatments, and the wider issues that can affect people with MS and their family or carers.
Want to know more?
Department of Health: NSF for long-term conditions (PDF, 127Mb)
NICE: Multiple sclerosis (PDF, 114kb)
Neurological Alliance: Publications and resources
Living with multiple sclerosis
A diagnosis of MS is life changing. You may need long-term treatment to control your symptoms and you may have to adapt your daily life.
Self-care is an integral part of daily life. It means you take responsibility for your own health and wellbeing, with support from people involved in your care. Self-care includes the things you do each day to stay fit, maintain good physical and mental health, prevent illness or accidents, and effectively deal with minor ailments and long-term conditions. People living with long-term conditions can benefit enormously if they receive support for self-care. They can live longer, have less pain, anxiety, depression and fatigue, have a better quality of life, and be more active and independent.
Because MS is a long-term condition, you'll be in regular contact with your healthcare team. A good relationship with the team means you can easily discuss your symptoms or concerns. The more the team knows, the more they can help you.
Everyone with a long-term condition such as MS is encouraged to get a flu jab each autumn to protect against flu (influenza). It's also recommended that they get an anti-pneumoccocal vaccination. This is a one-off injection that protects against a specific serious chest infection called pneumococcal pneumonia.
Healthy eating and exercise
Regular exercise and a healthy diet are recommended for everyone, not just people with MS. They help prevent many conditions, including heart disease and many forms of cancer. Try to eat a balanced diet, containing all the food groups, to give your body the nutrition it needs. Exercising regularly can help relieve stress and reduce fatigue.
Want to know more?
Your health, your way: What is self-care?
Multiple Sclerosis Trust: Diet factsheet (PDF, 136kb)
Multiple Sclerosis Society: Diet and nutrition
Multiple Sclerosis Society: Exercise and physiotherapy
Multiple Sclerosis Trust: Fitness and leisure
Relationships and support
Coming to terms with a long-term condition such as MS can put a strain on you, your family and your friends. It can be difficult to talk to people about your condition, even if they're close to you.
Dealing with the deterioration of symptoms, such as increasing difficulty with movement and tremors, can make people with MS very frustrated and depressed. Inevitably, their spouse, partner or carer will feel anxious or frustrated, too.
Be honest about how you feel and let your family and friends know what they can do to help. Don't feel shy about telling them that you need some time to yourself, if that's what you want.
If you have any questions, your GP or MS nurse may be able to reassure you. You may find it helpful to talk to a trained counsellor or psychologist, or to someone at a specialist helpline. Your GP surgery will have information on these.
Some people find it helpful to talk to other people who have MS, either at a local support group or in an internet chatroom.
Want to know more?
MS Society: MS Support
MS Society: Forum
MS Society: MS Helpline
Multiple Sclerosis Trust: My MS