MS is the most common neurological disorder among young adults and affects around 85,000 people in the UK. People are usually diagnosed between the ages of 20 and 40, but it can be later. Children can also get MS, but this is rare. It is more common in women than in men - the ratio is 3:2. You cannot catch MS.
Most commonly, MS is relapsing and remitting - which means that from time to time the condition flares up and then calms down; symptoms come and go. Over time, MS may progress further, causing disability, poor co-ordination and other symptoms.
MS is a complex condition involving many factors. There is no doubt that the fundamental problems occur in the central nervous system - the brain and spinal cord.
MS is the result of damage to a substance called myelin. Myelin is a protective sheath surrounding all the nerve fibres in the brain and spinal cord.
It works like insulating cable, helping to conduct electrical impulses between the brain or spinal cord and the rest of the body, and preventing them from being short-circuited. When myelin is healthy and functioning properly, electrical impulses get through quickly and efficiently allowing for easy and co-ordinated movement. When myelin is damaged, messages are slower, distorted, or non-existent and do not get through properly. This causes many of the symptoms of MS. Damaged areas of myelin are known as plaques or lesions.
Symptoms depend on the location of plaques. Myelin damage can affect nerves to the eyes, parts of the brain, the brain stem and spinal cord. Damage to motor nerves can affect movement. Damage to sensory nerves can result in numbness or tingling. There is nothing wrong with the actual muscles or sensory organs; it is simply that not all the right messages are getting through.
MS is not easy to diagnose. There are no tests which are specific for MS or 100 per cent conclusive. Some MS symptoms can also point to other conditions. A GP or neurologist will not diagnose MS until there have been at least two episodes involving at least two areas of the central nervous system on at least two separate occasions. These episodes must be at least one month apart and last for at least 24 hours. This means that there is an inevitable delay between the first symptom and a diagnosis of MS.
A clinical diagnosis, based on seeing your doctor for various MS-type symptoms over a period of time, needs to be backed up by tests. As abnormal results from these tests can also point to other illnesses, it may be necessary to have several tests to specifically isolate MS. A GP will usually refer a patient to a neurologist to make or confirm the diagnosis.
The following are the most common tests for MS, although there are others:
This method tests for abnormalities in nerve pathways, both motor and sensory. The neurologist looks for any changes in eye movements, limb co-ordination, balance, sensation, speech and reflexes, as well as any signs of weakness.
Evoked potentials test the time it takes for the brain to receive and interpret messages. This is a totally non-invasive and painless test. Small electrodes are placed on the head to monitor brain waves responding to stimuli to the eyes and ears. You will be asked to look at a screen which is made up like a giant black and white board. In a healthy person, the response is virtually instantaneous. If demyelination has taken place, messages take longer to get through.
The MRI (Magnetic Resonance Imaging) scanner is a high-tech piece of equipment, linked to a computer, which takes detailed pictures of the brain and spinal cord. It is very accurate and can pinpoint the exact location and size of plaques. Over 90 per cent of people with MS have plaques that show up on MRI scans. Despite this, it is not a conclusive MS test. Some people who are diagnosed with MS do not reveal any myelin damage on MRI scans. The MRI scanner is now used in most areas of the country to diagnosis MS.
This is a test which has been used for many years in the diagnosis of MS. A needle is inserted into the lower back, under local anaesthetic, and a small sample of cerebrospinal fluid (which flows around the brain and the spinal cord) is taken from the spinal cord. This fluid is tested for particular antibodies.
Conditions that mimic MS can be ruled out using other tests. These include CT (Computer Axial Tomography) scans which give a cross-sectional image of the brain; tests to reveal certain antibodies in the blood and inner ear tests to check balance.
MS has many factors and probable causes although a single causative agent has not been identified.
The environmental agent may be a virus or a bacterial infection. One theory is that a virus disturbs the immune system, or indirectly sets off an auto-immune process; this means that the immune system attacks itself. As scientists have been unable to find one particular virus which is responsible for MS, some researchers now think that a common virus may act as a delayed trigger.
It is thought that environmental factors are influential in the first 15 years of life. Many people with MS have had viral illnesses such as measles, chickenpox, flu, herpes or glandular fever as a child or a teenager.
Some people with MS have particular genes which give them a 'genetic predisposition' to MS, in other words make them more likely to develop the condition. These genes are also common in the general population.
There can be familial links between people with MS, but MS is not an inherited disease. In the UK the chances of a child having MS when a parent is affected are 20 to 40 times greater than for the general population. The lifetime risk in such cases is estimated to be three in 100, but this is still very small and much lower than that of developing cancer or heart problems. The risk of being affected by MS for the UK population in general is one in 1000.
Countries with temperate climates have a higher incidence of MS cases, and the condition is more common in areas in northern latitudes such as Scotland. No one knows why this is the case. Some studies have suggested that individuals who migrate to areas with temperate climates after the age of 15 retain the likelihood of developing MS corresponding to their country of origin, rather than developing the increased likelihood associated with temperate climates.
MS shows up differently in each person. Many people with MS are only mildly affected throughout their lives. At the other extreme a few people deteriorate rapidly from the beginning and can have a shortened life span. Most people with MS experience something in between these two scenarios.
There are four main types of MS, and a great deal of variability within each of them.
This type starts with a small number of mild attacks followed by complete recovery. It does not worsen over time and there is no permanent disability. The first symptoms are usually sensory.
It is only possible to classify people as having benign MS when they have little sign of disability 10 to 15 years after the onset of the disease. However, occasionally disability may develop even after many years of the disease remaining inactive. Around 20 per cent of people with MS have the benign form.
Most people with MS start with the relapsing-remitting type. This means they have attacks followed by remissions. During remission they have fewer or no symptoms.
Relapses (also known as attacks or exacerbations) tend to be unpredictable and their causes are unclear. During a relapse new symptoms may occur or previous symptoms may return. A relapse may last for hours, days, weeks or months and vary from mild to severe. At their worst, acute relapses may require hospital treatment.
Remissions are periods of recovery. They can last any length of time - often years. No one knows exactly what makes the disease process go into remission. Even during remission there will still be plaques visible on MRI scans.
In the early stages of relapsing-remitting MS, people are generally symptom-free during remissions. However, after several attacks, and as demyelination progresses, there may be some residual damage, resulting in the person being slightly more affected than before the relapse. Around 25 per cent of people with MS have the relapsing-remitting form.
This type starts in the same way as relapsing-remitting MS but after repeated attacks the remissions stop and the MS moves into what is known as the progressive phase.
Around 40 per cent of people develop secondary progressive MS. The time it takes to move into the secondary progressive phase varies. It usually happens within 15 to 20 years of the first onset of MS.
Some people with MS never have distinct relapses and remissions. From the start they experience steadily worsening symptoms and progressive disability. This may level off at any time, or may continue to get worse.
Around 15 per cent of people with MS have the primary progressive form of the disease, which is also known as chronic progressive.
MS varies considerably from one person to another. It can cause different symptoms which affect various parts of the body. Many people only experience a few of these symptoms and no one has all of them. It is possible to have a variety of symptoms at different times and although some symptoms are very common, there is not a typical set that applies to everyone.
Symptoms vary in severity and duration. They can be mild and short-lived, or severe and longer-lasting. Many are somewhere in between.
Some symptoms are more common in the early stages of the disease, while others occur later. They may be obvious to other people or hidden and 'silent' - difficult for people without MS to understand.
Symptoms may start with double or blurred vision, pain at the back of the eye or nerve pain in the face. Some people experience ringing in the ears or hearing problems, tingling ('pins and needles') or numbness in the legs, feet, arms or hands. Others experience giddiness and loss of balance, especially in the dark. Some people also find it hard to concentrate and may become forgetful, or experience anxiety, depression, or other changes in behaviour.
Other symptoms may include fatigue (especially in hot weather), weakness, difficulty in walking or muscle pain. Some people experience problems with speech or with bladder or bowel control. Men may find it more difficult to get an erection, although this can come and go like other symptoms, and both men and women may need more stimulation to stay aroused.
Without proper diagnosis, these symptoms are not necessarily specific to MS, and can be associated with a number of conditions. Treatments are available to help with most MS symptoms and should be discussed with a doctor or neurologist.
Certain triggers can rapidly produce symptoms, especially problems with eyesight and muscle weakness. The most common triggers tend to be overdoing it, heat and humidity, exercise which raises core body temperature, and fever.
(source: the MS Society UK Website)