The cause of MS is still unknown. Most researchers believe that it is an autoimmune disorder: for some reason, the immune system malfunctions and attacks myelin, the protective sheath around the central nervous system. Some studies show that MS may be triggered by a common virus and that some people are more vulnerable than others to this disease because of their genetic makeup. There is no proof that MS is a hereditary disease, but a certain number of genes probably contribute to making a person susceptible to multiple sclerosis.
MS attacks the myelin sheath around the nerve fibres in the brain and spinal cord, causing inflammation and often deterioration of the myelin. The resulting “lesions” or “plaques” block or alter nerve impulses. MS symptoms vary depending on the part of the nervous system that is affected.
The symptoms of MS are unpredictable and vary greatly from one person to the next. The list of possible symptoms is long, but you will not have them all:
Visual symptoms (double or blurred vision)
These problems may include diplopia (double vision), optic neuritis (inflammation of the optic nerve), nystagmus (rapid, uncontrolled eye movements), and in very rare cases, blindness (total loss of sight).
Debilitating fatigue that occurs suddenly or is unwarranted for the expended effort: this is one of the most frequent and most troublesome symptoms of MS.
Loss of balance and coordination
These symptoms may include loss of balance, tremors, ataxia (unstable gait), vertigo, awkwardness and lack of coordination.
Muscle stiffness (spasticity)
Altered muscle tone may cause spasticity or stiffness that interferes with mobility. Painful spasms may sometimes occur.
Weak leg muscles may alter gait.
These symptoms can include prickling, “pins and needles” (paresthesia) and a burning sensation in one part of the body. Trigeminal neuralgia, sharp pain in the face, may also be caused by dysfunction of one of the main facial nerves.
Many people with MS are sensitive to heat and their symptoms are intensified in a hot environment.
Difficulties speaking or swallowing
These problems can include slurred speech, poor articulation (dysarthria), changes in the pace of speech, and difficulty in swallowing (dysphagia).
Urinary and bowel problems
Bladder dysfunction may involve a frequent or urgent need to urinate, incomplete voiding of the bladder, or incontinence. Bowel problems may include constipation, and, less frequently, bowel incontinence (loss of bowel control).
These problems may include temporary impotence, reduced libido and altered sensation.
Difficulty remembering recent events and cognitive problems
These symptoms may include difficulty with short-term memory and concentration, and altered judgement or reasoning.
An attack is described as the occurrence of a new symptom or aggravation of an old symptom that lasts a minimum of 24 hours. It generally lasts two to three weeks, but recovery (sometimes partial) may take several months. For more information, see the article entitled MS Attacks: What they are and... what you can do about them.
At first, multiple sclerosis may show up as vague, intermittent symptoms. Many of the signs and symptoms of MS can be attributed to other diseases. This is why MS can sometimes only be diagnosed after a length of time and after a number of medical tests and examinations.
Generally the doctor – usually a neurologist – first makes sure that at least two different areas of the central nervous system are affected and that symptoms appeared at two different times. A diagnosis of MS is still mainly based on clinical examinations, because there is no specific diagnostic test for MS. Nevertheless, the medical history and certain tests are useful for establishing this diagnosis:
The doctor will ask you to describe the symptoms that you have felt so far.
The neurologist looks for any indication of neurological problems, the most frequent of which are vision difficulties, lack of coordination, weakness, lack of balance, altered sensation and reflexes, and speech difficulties.
Visual and auditory evoked potentials
When the nerve fibres lose their myelin, message transmission along the nerves may be slowed. Evoked potentials measure the time (speed of impulses along neurons) the brain takes to receive and interpret these messages. For this test, small electrodes are placed on the patient’s head to record brain waves caused by visual and auditory stimulation. If demyelination has occurred, the response to the stimuli will be delayed. Since this test is external (noninvasive) and painless, hospitalization is not required.
Magnetic resonance imaging (MRI)
MRI, done with a scanner, provides very detailed images of the brain and spinal cord and shows damaged areas (lesions or plaques). However, it cannot be considered conclusive because such plaques may be caused by other diseases. The MRI image, medical history, and results of neurological and other examinations are often used to confirm a diagnosis of MS.
In this examination, cerebrospinal fluid (the fluid that bathes and protects the brain and spinal cord) is sampled to look for specific antibodies. A fine needle is inserted between two lumbar vertebrae to remove a small amount of fluid. Although unpleasant, this procedure is generally not too painful.
Is it necessary to have MRIs of the brain AND the spinal cord to obtain a diagnosis of MS?
MS attacks the myelin in the brain and the spinal cord. Most myelin is in the brain, so it is more likely that lesions will be found there. The MRI examination is used to confirm the presence of lesions. The neurologist does not need to see them all to reach a diagnosis of MS. Also, a brain scan takes 30 minutes, while a scan of the spinal cord takes 60 to 90 minutes. If the brain scans are conclusive, it is not necessary to explore the spinal cord.
The progression of multiple sclerosis is unpredictable. However, over time, doctors can identify different courses or types of MS. Some people are not affected much by the disease (benign or relapsing-remitting form with no permanent disability), while others are hit hard. Most people are between these two extremes.
The main courses are:
relapsing-remitting course: characterized by clearly defined attacks, followed by partial or full remission – this is the most common form (70% at the time of diagnosis)
primary-progressive course: relatively rare (10% to 15% at the time of diagnosis), this form is characterized from onset by almost continuous progression, without any evident remission
secondary-progressive course: about half of MS patients start with a relapsing-remitting form, then their state begins to worsen within ten years of diagnosis and they risk becoming increasingly disabled
progressive-relapsing course: relatively rare form in which continuous progression is punctuated by attacks, without remission
Most people with multiple sclerosis start out with relapsing-remitting MS. In some of them, this first manifestation of the disease will gradually change into a secondary-progressive course that can make their disabilities worse. Others will only have light attacks that will not aggravate their condition: they have the benign form of MS.
MS is not a muscle disease, but it can affect the nerve systems that control muscles. The muscles then become weakened, not because they were affected, but because the nerve impulses do not reach them as well or not at all.
Since 1995, five treatments have been approved for relapsing-remitting MS and one is now available for secondary-progressive MS. During clinical trials, these treatments were able to change the progression of MS. They reduce the frequency and severity of MS attacks and the number of brain lesions. Some of them slow the progression of disabilities. There are also treatments to alleviate such symptoms as spasticity, bladder control, pain and fatigue. For more information, see the article entitled MS Disease-Modifying Therapies in Canada.
This is a low-dose chemotherapy used in relapsing-remitting MS for people who do not respond to the four immunomodulator treatments, or in progressive forms. It is administered intravenously in small quantities because a higher dose may be toxic, particularly for the heart.
Certainly. Researchers learn more every day about the causes of MS and are trying to find ways to prevent it. Research projects subsidized by the Multiple Sclerosis Society of Canada are focusing on the following topics:
Myelin repair or regeneration
Since MS destroys myelin, we are looking for a way to halt the activity of the disease and stimulate myelin regeneration – nearly 50% of the projects subsidized by the MS Society are myelin studies
The immune system attacks myelin, so it is essential to find out what is responsible for this attack and intercept it – 28% of the MS Society’s funding goes to immunological studies
Some researchers believe that common viruses may trigger MS attacks and are trying to identify them
The study of the role played by genes in MS has made great strides – the largest research project ever undertaken in the world on genetic susceptibility to MS is under way in Canada
MRI (magnetic resonance imaging)
Since the 1980s, researchers have been using MRI to “view” the living brain and MS lesions – this technology is used to speed up the diagnostic process and, no less important, to test new treatments; Canadian researchers are the leaders in this field
This new program funds projects on determining factors in health and on ways to help people cope with multiple sclerosis – areas subsidized are epidemiology, the cost of health, psychosocial effects of MS, and attitudes towards MS.
Multiple sclerosis most often strikes young adults – men and women between the ages of 15 and 40, the time when they are building a career and starting a family. The average age at diagnosis is 30, but MS can begin in children and in people over 50. Women are affected nearly three times as likely as men.
An estimated almost 20 000 Quebecers have multiple sclerosis. The frequency rate for this disease varies between 1 in 500 and 1 in 1000 depending on the region. Canada is a high-risk country for MS, because this disease is most widespread in countries far from the equator. Every day, nearly three people in Canada learn that they have MS.
Does a diagnosis of MS mean that I will be disabled?
A diagnosis of MS is often a shock, and the first thing that many people fear is becoming disabled. Fortunately, a diagnosis of MS does not necessarily mean that you will one day be disabled. Although most people with MS have to change their lifestyle over time and may need a mobility aid to get around, they lead very productive, satisfying lives.
For most people, MS is not fatal. In fact, most people with MS have a normal or nearly normal life expectancy because of the great strides that have been made in treating the symptoms of MS and in the search for new drugs.
MS is not considered to be a hereditary disease. However, close relatives of people who have MS have a slightly higher risk than the general population. The results of family studies suggest that the risk for a child who has a parent with MS is between 3% and 5%. This risk is considered low and the neurologist will not usually recommend avoiding pregnancy. The risk increases if several family members have MS or if the disease is present in both parents’ families.
Exposure to sun does not aggravate MS, but heat may intensify certain symptoms such as fatigue. For many people with MS, heat is very unpleasant. Each person has to decide for themselves and consult their neurologist if need be.
Since heat can exacerbate symptoms, should hot tubs be avoided?
Heat intolerance shows up quickly as certain symptoms (especially fatigue) are intensified. Most people with MS cannot tolerate spas or hot tubs. However, exposure to heat will not change the long-term progression of the disease. For people who can tolerate and enjoy hot tubs, there is no problem using them.
Can stress or a major emotional shock trigger a new attack?
Major stress or an emotional shock can increase the risk of an attack. By major stress, we mean the loss of a loved one, divorce, etc. This does not mean that an attack will necessarily occur after such a stressful event. Routine daily stress does not increase the risk of having an attack.
It is preferable to discuss this with the doctor, but unless he prohibits it, alcohol consumption is allowed. It may, however, intensify fatigue and aggravate balance and bladder problems. If these symptoms are present, it may be best to limit alcohol consumption. Of course, alcohol is prohibited while using certain drugs.
To date, there is no scientific proof that diet has an influence on the progression of MS. However, a balanced, varied diet improves resistance to infections. It can prevent infections with fevers that may trigger pseudo-exacerbations (temporary increases in symptoms caused by heat). For more information, see the Healthy Eating brochure.
Physical activity for a person with MS is a big step towards feeling better. It reduces fatigue, spasticity and pain and improves muscle tone, strength and overall endurance. It is essential that you remain active, but within your limitations. For more information, see the MS and Fitness brochure.
Canone of the four immunomodulator treatments (injections) be taken during pregnancy?
Women with MS need to plan pregnancies because treatments should be stopped six months before conception. For this reason, women who take such treatments should also use contraception. Before making the decision to have a child, there should be a frank discussion with the neurologist. For more information, see the Women's health and MS brochure.
Can a woman breastfeed while having one of the four treatments (injections)?
We do not know if the drugs are excreted in mother’s milk, so treatments should not be taken when a decision is made to breastfeed. The neurologist should help assess the advantages of restarting treatment earlier after childbirth and weigh the pros and cons. For more information, see the Women's health and MS brochure.