What is multiple sclerosis (MS)?

MS is a disease where patches of inflammation occur in parts of the brain and/or spinal cord. This can cause damage to parts of the 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 the 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 the nerve fibre.

Nerves are made up from many nerve fibres. Nerves come out of the brain and spinal cord and take messages to and from muscles, the skin, body organs and tissues.

What causes multiple sclerosis (MS)?

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 the body. When the disease is active, parts of the immune system, mainly cells called T cells, attack the myelin sheath which surrounds the nerve fibres in the brain and spinal cord. This leads to small patches of inflammation.

Something may trigger the immune system to act in this way. One theory is that a virus or another factor in the environment triggers the immune system in some people with 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 (MS) 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. A relapse is when 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.

Benign 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 (MS)?

About 1 in 600 people in the UK develop MS. It can affect anyone at any age, although it is rare in young children. It most commonly first develops around the age of 30. MS is the most common disabling illness of young adults in the UK. It is twice as common in women as in men.

MS is not strictly an hereditary disease. However, there is an increased chance of MS developing in close relatives of affected people. For example, a person with a mother, father, brother or sister with MS has about a 2 in 100 chance of developing MS (compared with about a 1 in 600 chance in the general population).

Multiple sclerosis (MS) symptoms

MS causes a wide variety of symptoms. Many people experience only a few symptoms and it is very unlikely that a person will develop all the symptoms described here. Symptoms of MS are usually unpredictable.

Some people find that their 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:

Visual problems

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 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.

Pain

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.

Fatigue

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 the skin. This is the most common symptom of a first relapse.
• Weakness or paralysis of some muscles. Mobility may be affected.
• Problems with your balance and co-ordination.
• Problems with concentration and attention.
• Tremors or spasms of some of your muscles.
• Dizziness.
• Problems with passing urine.
• Inability to have an erection in men.
• Difficulty with speaking.

Secondary symptoms

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 the bones (osteoporosis), muscle wasting and reduced mobility.

How is multiple sclerosis (MS) diagnosed?

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 the 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 the 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 the back. It takes a sample of some of the fluid that surrounds the 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 (MS) 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 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, fingolimod and mitoxantrone. 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 in each individual case. People who are prescribed these treatments are 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 below) provides an MS Decisions page which is designed to help patients decide which is the best medicine for them.

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 develop. They include:

• Physiotherapy.
• Occupational therapy.
• Speech therapy.
• Specialist nurse advice and support.
• Psychological therapies.
• Counselling.

What is the outlook (prognosis)?

MS affects different people in many different ways. This means that it is very difficult to predict the outlook for people with MS. There are currently no tests to predict how MS will progress in a person.

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 research into newer and better disease-modifying treatments brings hope that things may well improve in the future.

Research has shown that, on average, the degree of disability a person experiences five years after the onset on their MS is, on average, about three quarters of the expected disability at 10-15 years.

Note: the treatment of MS is a rapidly developing area of medicine. New treatments continue to be developed and the information on outlook above is very general. The specialist who knows your case can give more accurate information about the outlook for your particular situation.