Multiple sclerosis is a disorder of the brain and spinal cord. It can cause various symptoms. In most cases, episodes of symptoms come and go at first for several years. In time, some symptoms can become permanent and can cause disability. Although there is no cure for multiple sclerosis, various medicines and therapies may reduce the number of flare-ups and can help to ease symptoms and disability.
What is multiple sclerosis?
Multiple sclerosis (MS) is a disease where patches of inflammation occur in parts of your brain and/or spinal cord. This can cause damage to parts of your brain and lead to various symptoms (described below).
Understanding the brain, spinal cord, and nerves
Many thousands of nerve fibres transmit tiny electrical messages (impulses) between different parts of your brain and spinal cord. Each nerve fibre in the brain and spinal cord is surrounded by a protective sheath made from a substance called myelin. The myelin sheath acts like the insulation around an electrical wire. It is needed for the electrical impulses to travel correctly along your nerve fibres.
Nerves are made up from many nerve fibres. Nerves come out of your brain and spinal cord and take messages to and from your muscles, skin, body organs and tissues.
Multiple sclerosis causes
MS is thought to be an autoimmune disease. This means that cells of the immune system, which normally attack germs (bacteria, viruses, etc), attack part of your body. When the disease is active, parts of your immune system, mainly cells called T cells, attack the myelin sheath which surrounds your nerve fibres in the brain and spinal cord. This leads to small patches of inflammation.
Something may trigger your immune system to act in this way. One theory is that a virus or another factor in the environment triggers your immune system if you have a certain genetic makeup. Your genetic makeup is the material inherited from your parents which controls various aspects of your body.
The inflammation around the myelin sheath stops the affected nerve fibres from working properly and symptoms develop. When the inflammation clears, the myelin sheath may heal and repair and nerve fibres start to work again. However, the inflammation, or repeated bouts of inflammation, can leave a small scar (sclerosis) which can permanently damage nerve fibres. In a typical person with MS, many (multiple) small areas of scarring develop in the brain and spinal cord. These scars may also be called plaques.
How does multiple sclerosis progress?
Once the disease is triggered, it tends to follow one of the following four patterns.
Relapsing-remitting form of MS
Nearly 9 in 10 people with MS have the common relapsing-remitting form of the disease. In a relapse, an attack (episode) of symptoms occurs. During a relapse, symptoms develop (described below) and may last for days but usually last for 2-6 weeks. They sometimes last for several months. Symptoms then ease or go away (remit). You are said to be in remission when symptoms have eased or gone away. Further relapses then occur from time to time.
The type and number of symptoms that occur during a relapse vary from person to person, depending on where myelin damage occurs. The frequency of relapses also varies. Having one or two relapses every two years is fairly typical. However, relapses can occur more or less often than this. When a relapse occurs, previous symptoms may return, or new ones may appear.
This relapsing-remitting pattern tends to last for several years. At first, full recovery from symptoms, or nearly full recovery, is typical following each relapse. In time, in addition to myelin damage, there may also be damage to the nerve fibres themselves.
Eventually, often after 5-15 years, some symptoms usually become permanent. The permanent symptoms are due to accumulation of scar tissue in the brain and to the gradual nerve damage that occurs. The condition typically then slowly becomes worse over time. This is called secondary progressive MS. Typically, about two thirds of people with relapsing-remitting MS will have developed secondary progressive MS after 15 years.
Secondary progressive form of MS
There is a steady worsening of your symptoms (with or without relapses) in this form of MS. Many people with the relapsing-remitting form later develop this type of MS.
Primary progressive form of MS
In about 1 in 10 people with MS, there is no initial relapsing-remitting course. The symptoms become gradually worse from the outset and do not recover. This is called primary progressive MS.
In less than 1 in 10 people with MS, there are only a few relapses in a lifetime and no symptoms remain permanent. This is the least serious form of the disease and is called benign MS.
Who gets multiple sclerosis?
About 1 in 500 people in the UK develop MS. It can affect anyone at any age, although it is rare in young children. It often first develops in people aged between 30 and 50. MS is the most common disabling illness of young adults in the UK. It is more than twice as common in women as in men.
MS is not strictly an hereditary disease. However, you have an increased chance of MS developing if you have a close relative with MS. For example, if your mother, father, brother or sister has MS, then you have about a 2 in 100 chance of developing MS (compared with about a 1 in 500 chance in the general population).
Multiple sclerosis symptoms
MS causes a wide variety of symptoms. Many people experience only a few symptoms and it is very unlikely that you would develop all the symptoms described here if you have MS. Symptoms of MS are usually unpredictable.
You may find that your symptoms worsen gradually with time. More commonly, symptoms come and go at different times. Periods when your symptoms worsen are called relapses. Periods when your symptoms improve (or even disappear altogether) are called remissions.
Relapses can occur at any time and your symptoms may differ within each relapse. Although relapses usually occur for no apparent reason, various triggers can include infections, exercise and even hot weather. The symptoms that occur during a relapse depend on which part, or parts, of your brain or spinal cord are affected. You may have just one symptom in one part of your body, or several symptoms in different parts of your body. The symptoms occur because the affected nerve fibres stop working properly.
The more common symptoms include:
The first symptom of MS for around one in four people with MS is a disturbance of vision. Inflammation (swelling) of the optic nerve can occur. This is called optic neuritis. This can cause pain behind your eye and also some loss of your vision. This usually only affects one eye. Other eye symptoms may include blurring of your vision or having double vision.
Muscle spasms and spasticity
Tremors or spasms of some of your muscles may occur. This is usually due to damage to the nerves that supply these muscles. Some muscles may shorten (contract) tightly and can then become stiff and harder to use. This is called spasticity.
There are two main types of pain that may occur in people with MS:
- Neuropathic pain - this occurs due to damage to the nerve fibres. This can cause stabbing pains or a burning sensation over parts of your skin. Areas of your skin may also become very sensitive.
- Musculoskeletal pain - this type of pain can occur in any of your muscles that are affected by spasms or spasticity.
Extreme tiredness (fatigue) is one of the most common symptoms of MS. This tiredness is more than the tiredness you would expect after exercising or exertion. This fatigue can even affect your balance and concentration. There are different treatments for fatigue which are often a combination of self-management strategies, physiotherapy and exercise.
Emotional problems and depression
You may find that you laugh or cry more easily, even for no reason. Also, many people with MS have symptoms of depression or anxiety at some stage. It is important to see your doctor and talk about any of these symptoms you may have. Treatment for depression and anxiety is often effective.
Other symptoms which may occur include:
- Numbness or tingling in parts of your skin. This is the most common symptom of a first relapse.
- Weakness or paralysis of some muscles. Your mobility may be affected.
- Problems with your balance and co-ordination.
- Problems with your concentration and attention.
- Tremors or spasms of some of your muscles.
- Problems with passing urine.
- In men, inability to have an erection.
- Difficulty with speaking.
These are symptoms that may develop later in the course of the disease when some of the above symptoms become permanent. They may include contractures, urine infections, 'thinning' of your bones (osteoporosis), muscle wasting and reduced mobility.
Multiple sclerosis diagnosis
Almost all the symptoms that can occur with MS can also occur with other diseases. It is often difficult to be sure if a first episode of symptoms (a first relapse) is due to MS. For example, you may have an episode of numbness in a leg, or blurring of vision for a few weeks, which then goes. It may have been the first relapse of MS or just a one-off illness that was not MS.
Therefore, a firm diagnosis of MS is often not made until two or more relapses have occurred. So, you may have months, or years, of uncertainty if you have an episode of symptoms and the diagnosis is not clear.
Do any tests help?
In most cases, no test can definitely prove that you have MS after a first episode of symptoms or in the very early stages of the disease. However, some tests are helpful and may indicate that MS is a possible, or probable, cause of the symptoms.
A magnetic resonance imaging (MRI) scan of the brain is a useful test. This type of scan can detect small areas of inflammation and scarring in your brain which occur in MS. Although very useful in helping to make a diagnosis of MS, MRI scans are not always conclusive, especially in the early stages of the disease. A scan result should always be viewed together with your symptoms and physical examination.
Since MRI scans became available, other tests are now done less often. However, they are sometimes done and include:
- Lumbar puncture. In this test a needle is inserted, under local anaesthetic, into the lower part of your back. It takes a sample of some of the fluid that surrounds your brain and spinal cord. This is called cerebrospinal fluid (CSF). Certain protein levels are measured. Some proteins are altered in MS, although they can be altered in other conditions too.
- Evoked potential test. In this test, electrodes measure if there is slowing or any abnormal pattern in the electrical impulses in certain nerves.
Multiple sclerosis treatment
At present, although there is no cure for MS, certain symptoms of MS can often be eased. Treatments generally fall into four categories:
- Medicines that aim to modify the disease process.
- Steroid medication to treat relapses.
- Other medicines to help ease your symptoms.
- Other therapies and general support to minimise disability.
Medicines that aim to modify the disease process
These medicines are known as immunomodulatory agents. They include interferon beta, glatiramer, dimethyl fumarate, teriflunomide, alemtuzumab, natalizumab and fingolimod. These medicines do not cure MS and they are not suitable for everyone with MS. Natalizumab is a newer treatment for patients with more advanced and very active MS. Fingolimod, teriflunomide and dimethyl fumarate are the only tablet forms of disease-modifying treatment. All the others are given by injection.
Studies have shown that these medicines reduce the number of relapses in some cases. They may also have a small effect on slowing the progression of the disease. The exact way in which they work is not clear but they all interfere with the immune system in some way.
As there is still some uncertainty as to the role of these medicines and how effective they are, guidelines have been drawn up by the Association of British Neurologists as to when they may be prescribed on the NHS. A specialist (neurologist) will advise on whether one of the treatments is recommended for you. If you are prescribed any of these treatments you will be closely monitored. With the help of this monitoring, over time, it should become clear how effective the treatments are.
Each of the different disease-modifying medicines has pros and cons. The Multiple Sclerosis Trust (see under 'Further Reading', below) provides an MS Decisions page which is designed to help you decide which is the best medicine for you.
Newer medicines and combinations of medicines are also being studied.
Steroids (sometimes called corticosteroids)
A steroid is often prescribed if you have a relapse which causes disability. A high dose is usually given for a few days. Sometimes steroid tablets are used or the steroid may be given through your veins. The steroids work by reducing inflammation. A course of steroids will usually shorten the duration of a relapse. This means that your symptoms usually improve more quickly than they would otherwise have done.
However, steroids do not affect the ongoing progression of the disease.
Other treatments to improve symptoms
Depending on the symptoms that you develop, other treatments may be advised to combat the symptoms. For example:
- Anti-spasm medicines to ease any muscle spasms.
- Painkillers which are sometimes needed. There are specific types of painkillers which can improve neuropathic pain.
- Medicines which can help with some urinary problems that may develop.
- Antidepressant medicines which are sometimes advised if you develop depression.
- Medicines which can often help with erectile problems which may develop.
- There is debate as to the benefits of cannabis for people with MS.
Other treatments, therapies and support
A range of therapies may be advised, depending on what problems or disabilities you develop. They include:
- Occupational therapy.
- Speech therapy.
- Specialist nurse advice and support.
- Psychological therapies.
Multiple sclerosis prognosis
MS affects different people in many different ways. This means that it is very difficult to predict your outlook (prognosis) if you have MS. There are currently no tests to predict how your MS will progress.
Most people with MS will be able to continue to walk and function at their work for many years after their diagnosis. The majority of people diagnosed with MS will not need to use a wheelchair on a regular basis.
However, some people with MS do become disabled over time, and a minority become severely disabled.
The treatment of MS is a rapidly developing area of medicine. The research into newer and better disease-modifying treatments brings a great deal of hope that the outlook for people with MS will continue to improve in the future. The specialist who knows your case can give more accurate information about the outlook for your particular situation.
Further reading and references
Multiple sclerosis: management of multiple sclerosis in primary and secondary care; NICE clinical guideline (October 2014 - last updated November 2019)
Cannabis-based medicinal products; NICE Guidance (November 2019)
Scolding N, Barnes D, Cader S, et al; Association of British Neurologists: revised (2015) guidelines for prescribing disease-modifying treatments in multiple sclerosis. Pract Neurol. 2015 Aug15(4):273-9. doi: 10.1136/practneurol-2015-001139. Epub 2015 Jun 22.
Beta interferon and glatiramer acetate for treating multiple sclerosis; NICE Technology Appraisal Guidance (TA527), June 2018
Natalizumab for the treatment of adults with highly active relapsing-remitting multiple sclerosis; NICE Technology Appraisal Guidance, August 2007
Fingolimod for the treatment of highly active relapsing–remitting multiple sclerosis; NICE Technology Appraisal Guidance, April 2012
Dimethyl fumarate for treating relapsing‑remitting multiple sclerosis; NICE Technology Appraisal Guidance, August 2014
Lunde HMB, Assmus J, Myhr KM, et al; Survival and cause of death in multiple sclerosis: a 60-year longitudinal population study. J Neurol Neurosurg Psychiatry. 2017 Aug88(8):621-625. doi: 10.1136/jnnp-2016-315238. Epub 2017 Apr 1.
Introducing MS Decisions; Multiple Sclerosis Trust