Piecing together the clues

The following is extracted from the MS Society's 'What is MS?' booklet.

There are many things we know about MS, some of which still baffle us. We know what forms MS can take and how it can develop, but we are not sure why it does so. We have plenty of clues about the causes, but still cannot quite piece them together.

Treatments are available to help manage symptoms, including new drugs that can sometimes reduce relapses and so affect the course of MS.

MS is the most common neurological disorder among young adults and affects over 80,000 people in the UK. It is not infectious. People are usually diagnosed between the ages of 20 and 40, or sometimes later. In rare cases MS has been diagnosed in children. It is more common in women than in men - the ratio is 3 to 2.

The most common sort of MS is 'relapsing and remitting', which means that from time to time symptoms flare up and then calm down; they come and go. Over time, MS may progress further, causing disability, poor coordination and other symptoms.

MS is a complex condition involving many factors. We know that it affects the workings of the central nervous system - the brain and the spinal cord.

How does MS happen?

MS symptoms result from damage to myelin, the protective coating surrounding all the nerve fibres in the brain, the eye and the spinal cord. Myelin works like insulating cable, helping to conduct messages quickly and efficiently between the brain or spinal cord and the rest of the body.

When myelin is damaged, messages are slower or distorted or do not get through at all. Damaged areas of myelin are known as plaques or lesions.

Myelin damage causes symptoms

The nature of MS symptoms depends upon where damage occurs to myelin in the central nervous system. Damage to nerves responsible for movement can result in poor coordination. Damage to nerves responsible for sensation can result in numbness or tingling. There may be nothing wrong with actual muscles or senses; it is simply that not all the right messages are getting through.

How is MS diagnosed?

MS is not easy to diagnose. A neurologist will not usually diagnose it until there have been at least two occurrences of symptoms involving different areas of the central nervous system. It may be necessary to have several different tests to identify MS, and the most common tests are:

· Neurological examination - to find changes in eye movements, coordination of legs or hands etc.
· 'Evoked potentials' - a test to find the time it takes for the brain to receive and interpret messages. Electrodes are used but the test is non-invasive and painless.
· MRI scan - computer images of the brain and spinal cord.
· Lumbar puncture - a needle is inserted into the lower back under local anaesthetic and a small sample of cerebrospinal fluid is taken.

What causes MS?

Many factors are involved but no single cause has been identified:

· Environment - a virus or bacterial infection may be involved and some scientists believe that a virus disturbs the immune system or indirectly sets of a process whereby the immune system attacks itself.
· Genetic factors - although there is no single gene linked to MS, some people do seem to have particular genes, which give them a 'genetic predisposition' to MS.
· Family links - MS is not hereditary but it can occur in more than one family member.
· Climate and geography - countries with temperate climates have a higher incidence of MS cases and MS is more common in areas in northern latitudes such as Scotland. It is not clear why this is the case.

Are there different types of MS?

There are four main types of MS and a great deal of variation within each. MS shows up differently in each person.

· Benign MS - this starts with a small number of mild attacks followed by complete recovery. People are only classified as having benign MS when they have little sign of disability 10 to 15 years after the onset of symptoms. About 20% of people with MS have this form.
· Relapsing-remitting MS - relapses (also known as attacks or exacerbations) tend to be unpredictable and can last for hours, days, weeks or months. They can vary from mild to severe and during a relapse new symptoms may appear. Remissions can last any length of time and symptoms usually disappear. After several attacks there may be some residual damage to the myelin, resulting in the person being slightly more affected than before the relapse. About 25% have this form.
· Secondary progressive MS - Many people start with relapsing-remitting MS and then develop secondary progressive MS. This means that disability does not go away after a relapse and progressively worsens between attacks. About 40% of people with MS develop this form, usually after 15 to 20 years from the initial onset of MS.
· Primary progressive MS - Some people with MS never have distinct relapses or remissions and from the start they experience steadily worsening symptoms. About 15% have this form (also known as chronic progressive).

What are the symptoms?

MS varies from person to person and no one experiences every symptom.

Symptoms vary in severity and duration. They can range from mild and short-lived to severe and long-lasting. Some symptoms such as pain and fatigue are hidden and may be harder for people unfamiliar with MS to understand.

Certain triggers seem to make symptoms worse. The most common tend to be overdoing things, exercise which raises core body temperature, fever, heat and humidity.

Symptoms can start with double or blurred vision, pain in the back of the eye or nerve pain in the face. Some people experience ringing in the ears or hearing problems, tingling or numbness in the legs, feet, arms or hands. Others experience giddiness and loss of balance, especially in the dark.

Some may find it hard to concentrate, become forgetful or experience anxiety, depression or mood swings. Other symptoms may include fatigue, pain, and problems with speech, bladder or bowel control. Sexual function or sensation can be affected and a person may need more stimulation to remain aroused.

There are many effective treatments and they should be discussed with a doctor or an MS nurse.

People who have been diagnosed with MS recently may feel a sense of loss or bereavement and may experience shock or bewilderment. They may also feel angry and want to deny the diagnosis. All these reactions are normal. The MS Society's booklet 'Making the most of life with MS' has information on coping with these reactions.

The free phone MS Helpline, counselling lines and local contacts are there to help and support people with MS, whether they are newly diagnosed or have been living with the condition for many years.