The Diagnosis of Multiple Sclerosis

Transcription

1 The Diagnosis of Multiple Sclerosis by Dr. J. Marc Girard, Neurologist, MD, FRCP(c) 3 rd edition

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3 A NEUROLOGIST HAS JUST GIVEN YOU A DIAGNOSIS of multiple sclerosis. Or you recently underwent a magnetic resonance imaging scan of your brain and your family doctor says that it may have detected multiple sclerosis lesions. Or maybe you have been having strange neurological symptoms and you are afraid you may have multiple sclerosis. If any of these situations applies to you, this brochure is for you. In the following pages, we will describe the data a physician needs to make a clinical diagnosis of multiple sclerosis (MS) and the use of laboratory examinations to confirm it. After reading it, you will understand that diagnosis is not always easy; that it may require a long period of observation by your doctor, which means uncertainty for you; and that even though magnetic resonance imaging (MRI) is extremely useful for diagnosis, it may provide false results and thus it cannot be used alone to diagnose this disease. We hope you find this information useful! 2

4 CLINICAL DIAGNOSIS OF MS For some diseases, it is easy to make a diagnosis just by doing certain laboratory tests. Thus, diabetes can be diagnosed by means of a simple blood test revealing a high sugar level, while a lung X-ray showing an area of consolidation is diagnostic of pneumonia. The increased blood sugar and the consolidation on the X-ray are biological markers that are specific to these diseases. In the case of MS, there are no really specific markers. Even though MRI has made a huge contribution to the diagnosis of MS in recent years, the physician must base the diagnosis first and foremost on the history you give him (symptoms) and the anomalies he sees during your neurological examination (signs). MRI as a test method is indeed very sensitive, as it rarely misses MS lesions if they are present; however, it is not very specific, in the sense that something that looks abnormal on the MRI, raising the possibility of MS, may simply be a variant of normality. So a physician must be cautious in making a diagnosis of MS. He may sometimes be aided by other tests such as the search for oligoclonal bands in the fluid that is sampled during a lumbar puncture or visual evoked potentials, which may reveal certain deficits. To reach a diagnosis of multiple sclerosis, the physician must be sure that two different areas (criterion of dissemination in space) of the white matter in the central nervous system (brain and spinal cord) have sustained damage that cannot be explained by other illnesses. He must also show that these attacks occurred at two different times in the progression of the illness (criterion of dissemination in time). Diagnosis will be easy if the attacks were serious (paralysis, for example) with a short interval in between. On the other hand, it will be much more difficult if the symptoms are slight (numbness) and spread over a long period. When the first medical evaluation is completed, the questionnaire is crucial in order to understand 3

5 the symptoms that led you to seek medical attention and to find out if, in your medical history, there have been any signs of neurological attacks. Some of these you may report without any prompting; others you may have forgotten because they were benign or because you did not think they were related to the illness: the physician s questions will remind you of them. In the neurological examination, the clinician will search for either objective signs confirming the symptoms reported at the time of the consultation, or slight abnormalities, unnoticeable in everyday life, that are after-effects of past symptoms which have regressed. In this first evaluation, the doctor always tries to demonstrate the aforementioned main principle: an attack on the white matter with dissemination in time and space. 4

6 SYMPTOMS OF MS Because MS is essentially a disease of the white matter in the central nervous system, the symptoms that may be exhibited are many and varied, and depend on the location of the plaque in the brain. As other neurological illnesses may attack the white matter, none of the symptoms found in MS are specific to that disease. It is the progression of these signs, that is to say, their appearance and disappearance, among individuals from 10 to 60 years old, that is specific to multiple sclerosis. The following tables show the frequency rate of the symptoms present as first signs of the illness (table 1) as well as the frequency rate of the appearance of these symptoms as the disease progresses (table 2). TABLE 1 Frequency of Symptoms as the First Signs of MS Numbness in the limbs 30-50% Fatigue 20% Problems with balance or walking 18% Double vision (diplopia) 17% Loss of vision in one eye 16% Dizziness 14% Paralysis of lower limbs 10% Urinary problems 10% 5

7 TABLE 2 Frequency of Symptoms Reported During Progression of the Illness Numbness 90% Weakness in both legs 90% Fatigue 80% Urinary problems 80% Problems with balance 50-80% Loss of vision in one eye 65% Weakness of a limb 52% Sexual difficulties 50% in women 75% in men Memory problems 50% Problems with coordination 45% Double vision (diplopia) 40% Abnormal sensations 40% Pain 40% Lhermitte s sign 30% Facial paralysis 15% Facial pain (painful twitch) 10% Epilepsy 5% Hearing loss 4% Ref.: Paty DW, Ebers GC, Multiple Sclerosis, Philadelphia: FA Davis, 1997:

8 Problems with Balance or Walking Balance and walking require the harmonious coordination of several regions of the central nervous system. A plaque in one of these areas may be sufficient to destroy this control. Thus, a lesion on the spinal cord may entail weakness in both legs (paraparesis) which starts discreetly, such as abnormal fatigue when walking or running, or difficulty climbing stairs or getting up out of a chair. In the most serious cases, walking can be so difficult that the use of a cane or wheelchair becomes necessary. With this weakness may come spasticity, which appears as a sensation of stiffness in the legs. In people who are affected more seriously, spasticity may cause painful spasms which may appear spontaneously or after stimulation, such as turning over in bed at night. When the part of the nervous system called the cerebellum is affected, the patient will have a gait similar to someone who is drunk: a constant tendency to disequilibrium, making it difficult to walk in a straight line. The patient constantly looks for support to remain upright, walks with legs spread apart for balance, or has difficulty grasping objects with his hands, because of either a coordination problem or trembling in the arms. Problems with walking may be linked to dizziness or vertigo. The patient notices a sensation of spinning a moving floor that is worsened by changes in position and may be accompanied by nausea and vomiting. These symptoms, which are due to a plaque in the vestibular region the balance centre in the brain are generally of short duration. 7

9 Paralysis As mentioned previously, paralysis appears as a weakness in one or both legs that makes walking difficult, or as a difficulty in using an arm or hand that may be accompanied by weakness in the leg on the same side of the body, or by facial distortion. Sensory Manifestations Generally, the patient describes sensory manifestations as a sensation of tightness around the chest, numbness and prickling, or sometimes as painful sensations like stings, burns and electric shocks in the body or limbs. These sensory problems will have a distinctive distribution, sometimes affecting only the hands or feet, sometimes both legs and part of the abdomen and torso and sometimes the arm and leg on the same side, always depending on the location of the plaque in the brain or spinal cord. Patients for whom a sensory attack is the first sign of the illness make up the group for whom the diagnosis of MS is the most difficult. In fact, although numbness is frequent in MS, not everyone with numbness suffers from this disease. Moreover, if the patient has not had other symptoms of MS in the past, the neurological examination will often be normal. One particular manifestation of the illness is the Lhermitte s sign, named in honour of the French neurologist who described it. The patient notices that bending his head forward brings on a momentary electric shock that shoots through his shoulders to his hands and fingers and sometimes down along his back into his legs. This frequent symptom is due to the presence of a plaque in the spinal cord in the neck, but once again is not specific to MS, as it is found in other illnesses. 8

10 Vision Problems One of the most alarming symptoms of the disease is the partial loss of vision in one eye: this is optic neuritis and is caused by a plaque on the optic nerve. This inflammatory attack starts with blurred vision and can progress in just a few days to complete loss of sight. There may also be pain that increases with eye movement. Fortunately, blindness is reversible in most cases, leaving vision that is sometimes slightly blurred, worse in the centre of the field of vision (scotoma), with reduced colour perception in the affected eye that is sometimes imperceptible to the patient. Another visual problem is double vision or diplopia, which does not generally appear unless the patient looks in certain directions. Fatigue H V C K Z H V D S O C V R K N H O C K D V R Z S V D K R D S Z C O S H N O R C People with MS often feel tired and some find this to be the worst symptom of all. The fatigue is abnormally severe, sometimes forcing the patient to rest during the day because he is completely worn out, despite light or normal activity. This fatigue often persists beyond the attack periods. It is frequently accompanied by intolerance to any increase in body temperature due to hot weather, physical effort, hot baths, saunas, or even a fever. On occasion, these conditions are conducive to the reappearance of past symptoms which had disappeared (weakness or loss of vision). These are alleviated once the temperature returns to normal (pseudo-exacerbations). 9

11 Urinary Difficulties and Constipation The most frequent urinary symptom in MS is the sensation of urgency felt by the patient, requiring frequent urination, day and night. In fact, attacks on the spinal cord cause the bladder to lose its capacity to accumulate urine. Urine is constantly eliminated by the kidneys, so as soon as there is a small amount of urine in the bladder, it starts contracting, meaning the patient has to head for the washroom to avoid having an accident. When it comes to the bowels, however, the opposite is often true, and many people with MS complain of constipation. Sexual Difficulties For men, sexual problems generally take the form of difficulty achieving and maintaining an erection, while women show signs of decreased vaginal sensitivity during penetration, or difficulty reaching orgasm. These difficulties are generally secondary effects of the lesions on the spinal cord, often the same as those responsible for urinary difficulties. 10

12 Memory Problems In recent years, various studies have shown that about 50% of MS patients suffer from memory loss. These problems are usually slight, but for some people, they can interfere with their work or daily lives. Difficulty remembering things or concentrating is often related to fatigue. Other Symptoms Other signs are found less frequently. Loss of hearing in one ear can be associated with MS, but one must be certain that other illnesses are not responsible before concluding that it is, in fact, MS. There may be sudden movements of the limbs that last only a short time but occur several times a day. These spasms can easily be treated with appropriate medication and generally return to normal after a few weeks. Finally, MS can give rise to paralysis of one side of the face (Bell s palsy) or to a sharp pain on one side of the jaw or the gums (trigeminal neuralgia), which may occur several times a day but can also be alleviated with appropriate medication. 11

13 SIGNS OF MS In the neurological examination, the physician tries to objectively explain the symptoms that led you to consult him, and will search for abnormalities that show evidence of previous attacks. The physician will carefully examine your vision, evaluating your visual acuity in each eye by asking you to read an eye chart while you are wearing your corrective lenses. A previous attack on the eye may have left slight abnormalities. He will look inside your eye with an ophthalmoscope to observe the optic nerve at the very back, which appears very pale following optic neuritis. He will ask you to look in different directions, to find out whether the muscles used for eye movement and responsible for double vision are paralyzed. He will check to see if your eyes jump around in an abnormal fashion (nystagmus), a condition frequently encountered in MS. He will also observe your face, looking for small after-effects of earlier paralysis, and will check the back of your throat to make sure there are no abnormalities that might make swallowing difficult. Afterwards, he will check the muscle strength in your arms and legs. It is not unusual to note small differences in the strength of limbs that were affected in the past but have recovered. These abnormalities are not easily noticed, but do not generally escape the eye of an experienced clinician. The physician will also verify your muscle tone to detect and assess spasticity. Reflex testing may seem amusing to you during the examination but it is essential for the clinician s conclusions. He will check to see if your reflexes are more active than normal. Heightened reflexes, even more than muscle weakness, may be the only sign that remains from an old paralysis that the patient has recovered from. 12

14 The physician will also pay close attention to the plantar skin reflex obtained by scraping the outside of the sole of the foot with a pointed object. Normally, the toes flex downwards towards the sole, but in the case of an old paralysis, the toes will point upwards. This is Babinski s sign. The presence of this sign, heightened reflexes and weakness all confirm to the clinician that the patient s paralysis was definitely caused by an attack on the central nervous system. The evaluation of sensory functions can be misleading because, despite the presence of severe numbness, it frequently happens that no objective deficiency is found during the examination. The neurologist will then evaluate several sensory functions that are not mediated by the same regions of the brain: touch, using a facial tissue. vibration sense, using a tuning fork on your fingers and toes, as well as position sense by asking you to close your eyes and identify in which direction the examiner is moving your thumb or big toe. sensitivity to pain, using a sharp needle and asking you to compare your perception of the prick from one part of your body to the other. Always make sure that the physician uses a new needle for each patient, given the risks that now exist for transmitting illnesses by needle. more rarely, when indicated, the physician will evaluate your perception of temperature by asking you to distinguish between tubes of hot and cold water applied to your skin. 13

15 You will surely remember the part of the examination where the doctor asks you to touch your nose with your index finger and then touch his finger, which he keeps moving around. With this test, the neurologist evaluates your cerebellum, the brain s coordination centre. When you have difficulty finding the target, when movement is not smooth, or when a slight trembling appears before you reach the target, he diagnoses an attack on the cerebellum. The physician will also check for abnormal functioning of the cerebellum by asking you to rapidly tap each of your fingers on your thumb or to turn your hand quickly at the wrist as you would when screwing in an electric light bulb (marionette test). He may just watch you walk. Simple observation of a person s gait is essential since an informed clinician can determine the extent of spasticity, weakness, or cerebellum problems that are responsible for walking difficulties. 14

16 LABORATORY DIAGNOSIS OF MS Once the questionnaire and neurological examination are completed, the physician has a number of elements suggesting the diagnosis of MS. Laboratory tests have several objectives in confirming this diagnosis. If the clinical evaluation does not reveal a previous attack on the white matter, the laboratory tests may reveal some lesions that were not discovered in the clinical examination and confirm the presence of a second lesion. The clinician will also use the tests to ensure that this is not a case of another illness imitating MS. When the diagnosis is known, he may use tests to follow the progression of the illness. What are these laboratory examinations? Magnetic Resonance Imaging (MRI) The arrival on the scene of magnetic resonance imaging has revolutionized the diagnosis of multiple sclerosis. For the first time, physicians have a tool that is able to see plaques in the brain, which could not be done with the CT scan. On the other hand, MRI cannot be used alone to make a diagnosis of MS. Several other diseases can resemble MS on the image, and even healthy people may have an MRI result with abnormalities resembling those that result from MS, although they will never have the disease. Thus, MRI is simply an aid to the physician s diagnosis. 15

17 Because of our better understanding of MRI, radiologists now use new criteria to interpret the results obtained with this technology. These criteria enable the neurologist to more easily identify patients who are at a high risk of having or developing the disease. Because of the confidence that MRI can give, certain patients who have only had one episode of neurological problems can be told by a neurologist that they have a high probability of having MS, even if they have not yet had a second attack. These patients are part of a new category among the types of multiple sclerosis: Clinically Isolated Syndrome (CIS). In some of these cases, the neurologist may immediately suggest treatment for MS. Cerebrospinal Fluid (CSF) Although it is less widely used than it was before the arrival of MRI, lumbar puncture is still useful in establishing a diagnosis of MS. The information it provides is different from, and complementary to, that obtained in the clinic or with MRI. Lumbar puncture (spinal tap) involves taking a sample of the cerebrospinal fluid, which circulates through the brain and spinal cord. The test is done by inserting a needle into the lower back between the vertebrae. The analysis of the CSF can detect an abnormal increase in certain proteins and in IgG (a type of antibody), and the presence of oligoclonal bands, which also result from abnormal production of antibodies. However, these tests are not always abnormal in people with MS, and people who have anomalies may actually have other diseases. Consequently, lumbar puncture will be useful in cases where the clinical and MRI data do not allow one to make a firm diagnosis. 16

18 Evoked Potentials With this procedure, it is possible to evaluate the time it takes for a visual, auditory or sensory message to reach the brain. In MS, it is not unusual to find a slower speed of transmission of information to the brain. Visual evoked potentials are often abnormal in MS because the optic nerves are frequently damaged, so this test can be an opportunity to uncover a history of mild optic neuritis that may have gone unnoticed. The test consists of having you sit in front of a television screen, staring at the image of a checkerboard that flashes. By applying electrodes to the back of your head and using a computer plugged into the machine, it is possible to calculate the average time it takes for a visual stimulus to travel from the retina to your brain. Longer visual evoked potentials represent another way of confirming that the disease is disseminated in space. Conclusion MS can be difficult to diagnose. Consequently, this must be done by an experienced physician, generally a neurologist. The diagnosis depends, first and foremost, on the demonstrated existence of multiple lesions dispersed throughout the central nervous system, as proven by the patient history, neurological examination and certain laboratory tests. In recent years, we have seen some major advances in our understanding of MS and in the diagnosis and treatment of this disease. These impressive developments give healthcare professonals who are involved in helping people with this disease real hope that great strides will soon be made in the treatment of MS. 17

19 About the author: Dr. J. Marc Girard is a neurologist, and has been a member of the neurology department at with CHUM Hôtel- Dieu Hospital, in Montreal, since He has also practised at the multiple sclerosis clinic at Notre-Dame Hospital for a number of years. He has taken part in numerous research protocols on the use of various drugs in the treatment of multiple sclerosis, including the study of the first medication found to actually treat the disease, Betaseron. Dr. Girard has been active within the Quebec Division of the Multiple Sclerosis Society of Canada for several years now. In 1996, he was very much involved in the public campaign that led the Quebec government to agree to reimburse interferon beta-1b. He was a member of the Quebec Division s board of directors for five years and has been on the editorial committee of the quarterly newsletter MS Quebec and the website for over 16 years! He gives freely of his time and often presents lectures, in person or online, and answers the questions of people with MS on the Ask the Expert web page of the Multiple Sclerosis Society of Canada at Production: Text: Translation: : Review: Graphic Design: Printing: Multiple Sclerosis Society of Canada, Quebec Division Dr. J. Marc Girard Zofia Laubitz Dr. J. Marc Girard, Zofia Laubitz, Jennifer Burgess Pevec and Diane Rivard. Kaki Design inc. Impression Trans-Graphique inc. Did you like this publication? Did you find it useful? Please share your comments and suggestions with us (see the address on the back). Note: The masculine gender has been used to make the text more readable. ISBN (first edition, 2000 and reprinted, 2002) ISBN (2006 edition) Multiple Sclerosis Society of Canada, Quebec Division 2006, 3 rd edition Legal deposit 4 th quarter 2006 Bibliothèque et Archives nationales du Québec National Library of Canada Multiple Sclerosis Society of Canada, Quebec Division 2006

20 550 Sherbrooke Street West East Tower, Suite 1010 Montreal, Quebec H3A 1B9 Telephone: Toll-free number: Fax: or (toll-free) Internet: Our Mission To be a leader in finding a cure for multiple sclerosis and enabling people affected by MS to enhance their quality of life. This publication was produced thanks to an unconditional grant from