by Dr. J. Marc Girard MD FRCP (C) 2nd Edition Multiple Sclerosis Society of Canada Quebec Division

Transcription

1 by Dr. J. Marc Girard MD FRCP (C) 2nd Edition Multiple Sclerosis Society of Canada Quebec Division

2 Production: Multiple Sclerosis Society of Canada (Quebec Division) Text: Dr. J. Marc Girard, MD FRCP(C) First published, 2000, revised Review:Dr. J. Marc Girard, Barbara McClintock, Paroles écrites and Diane Rivard Translation: Paroles écrites Graphic Design: Mardigrafe inc. Printing: Imprimerie Art 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 Multiple Sclerosis Society of Canada (Quebec Division) 2002, 2nd edition Legal deposit 2nd quarter 2002 Bibliothèque nationale du Québec National Library of Canada Multiple Sclerosis Society of Canada (Quebec Division) 2002

3 The Diagnosis of Multiple Sclerosis by J. Marc Girard, MD FRCP(C) Diagnosing multiple sclerosis has become easier in recent years with the advent of such new laboratory technologies as magnetic resonance imaging (MRI). In addition, drugs that can modify the progression of the disease now exist, so rapid diagnosis has become very important. Despite all these developments, diagnosis of MS does not depend entirely on laboratory tests. The physician will primarily base his diagnosis on clinical data obtained from a detailed questionnaire that he will fill out with you, and a thorough neurological examination to determine if there have been at least two attacks of multiple sclerosis in your medical history, at two different times in your life, and affecting two different parts of your brain. Laboratory tests such as MRI, evoked potentials and lumbar puncture do not replace clinical data: they are complementary to it. Diagnosing multiple sclerosis is like assembling a jigsaw puzzle: when the various pieces are put together the questionnaire, neurological examination and lab tests they result in a definite diagnosis. Of all these pieces, the questionnaire and the examination are definitely the most important. 1

4 I CLINICAL DIAGNOSIS OF MS 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 the symptoms that led you to seek medical attention and to find out if, in your medical history, there were 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 2

5 you did not think they were related to the illness: the physicians 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, 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. 3

6 A 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 of the symptoms present as first signs of the illness (table 1) as well as the frequency of the appearance of these symptoms as the disease progresses (table 2). 4

7 TABLE 1 Frequency of Symptoms as the First Signs of MS Numbness in the limbs 33% Problems with balance or walking 18% Loss of vision in one eye 17% Double vision 13% Paralysis 10% Facial sensory attack 3% Lhermitte symptom 3% Pain 2% TABLE 2 Frequency of Symptoms Reported During Progression of the Illness Problems with balance 78% Numbness 71% Fatigue 65% Weakness in both legs 62% Urinary difficulties 62% Sexual difficulties 60% Loss of vision in one eye 55% Weakness of a limb 52% Memory loss 50% Problems with coordination 45% Double vision 43% Abnormal sensations 40% Pain 25% Facial paralysis 15% Epilepsy 5% Hearing loss 4% Facial pain (painful twitch) 2% 5

8 1) 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 break 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, 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. Among those 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, either because of 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 augmented by changes in position and may be accompanied by nausea and vomiting. These symptoms, which are due to a 6

9 plaque in the vestibular region the balance centre in the brain are generally of short duration. 2) 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. The limbs affected by paralysis vary depending on the location of the plaque in the brain. If the plaque affects the right side of the brain, the paralysis will show up in the left side: the arm, the leg, and sometimes half of the face. If the plaque is the spinal cord, the paralysis will affect both sides of the body: both legs only, if the plaque is located in the lower spine, or the arms and legs, if the plaque is located in the neck area of the spinal cord. 3) Sensory Manifestations Generally, the patient describes sensory manifestations as a sensation of tightening around the thorax, 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, as described in the above paragraph. 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, 7

10 not everyone with numbness suffers from this disease. Moreover, if the patient has not had other symptoms in the past, the neurological examination will often be normal. One particular manifestation of the illness is the Lhermitte symptom, 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 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 limited to MS, as it is found in other illnesses. 4) Vision Problems One of the most alarming symptoms of the disease is the loss of sight in one eye: this is optic neuritis and is caused by a plaque on the optic nerve. This condition starts with blurred vision and can progress in less than one day to complete loss of sight. There frequently is also pain that increases with eye movement. Fortunately, the 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 symptom is double vision or diplopia, which does not generally appear unless the patient looks in certain directions. 8

11 5) Fatigue Fatigue is a very frequent symptom of MS. It is abnormal, sometimes obliging 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 heat due to the weather, physical effort, hot baths or 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 correct themselves once the temperature returns to normal (pseudo-exacerbations). Contrary to the other symptoms of multiple sclerosis, fatigue is not related to a plaque located in a particular spot in the brain. The cause of this fatigue is still unknown. 6) Urinary Difficulties and Constipation The most frequent urinary symptom 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 con- 9

12 stantly eliminated by the kidneys, so as soon as there is less than half a cup of urine in the bladder, it starts contracting, obliging the patient to head for the toilet or have an accident. Sometimes, when the disease is more advanced, the bladder becomes lazy and urination becomes more difficult. For people with MS, the most common intestinal problem is constipation. Another problem which occurs, but less frequently, is anal incontinence (loss of control over intestines). 7) Sexual Difficulties For men, sexual difficulties may be related to obtaining and maintaining an erection, while women show signs of diminishing 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. 8) Memory Loss In recent years, various studies have shown that about 50% of MS patients suffer memory loss. Their problems are usually slight, but for some people, this can interfere with their work or daily lives. Difficulty remembering things or concentrating is often related to fatigue. 9) 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, 10

13 MS. Some multiple sclerosis attacks may have paroxysmal symptoms, i.e. brief symptoms that last several seconds or minutes but occur several times a day. The best known of these paroxysmal symptoms are trigeminal neuralgia, a sharp pain on one side of the jaw, and tonic seizure, an abrupt, repeated spasm in a limb. 11

14 B 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 with the aid of 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 and which appears very pale following optic neuritis. He will ask you to look in different directions, searching for paralysis in the muscles used for movement and responsible for double vision. He will check to see if your eyes jump around in an abnormal fashion (nystagmus), a condition frequently encountered in MS. He will observe your face, looking for after-effects of previous 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 12

15 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 the reflexes in an individual with MS are more active by comparing them with those of a healthy person of the same age. He will also compare the reflexes on one side of the body with those on the other side for the same person, and the reflexes in the legs with those in the arms. Heightened reflexes, more than muscle strength, may be the only sign that remains from an old paralysis that has recuperated. 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 reflex. The 13

16 presence of this sign, augmented 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 is often disappointing 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 controlled 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 moves 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. 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 cere- 14

17 bellum, the brain s centre of coordination. When you have difficulty finding the target, when movement is not smooth, or a slight trembling appears before you reach the target, an attack on the cerebellum is indicated. The physician will also check for abnormal operation 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. 15

18 II 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 for the final 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 that confirm the presence of a second lesion. The clinician will also use the tests to ensure that there has not been 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? 1) Imaging The use of magnetic resonance imaging (MRI) in recent years has revolutionized the diagnosis of multiple sclerosis. This technique is used to see plaques in the brain that could not be viewed previously with the CT-scan. This technique is very sensitive, meaning that it frequently shows several plaques that are not related to the symptoms you feel. These plaques are proof of previous slight attacks or attacks that did not cause any symptoms. 16

19 Since this test is becoming increasingly reliable, it is now used more to expedite diagnosis. Patients who have had a first attack of MS and for whom MRI reveals several plaques will be diagnosed with monosymptomatic multiple sclerosis. These are patients whose diagnosis is not completely certain, because there have not been two attacks at two different times, but for whom the risk of developing the disease is sufficiently high, in some cases, to justify preventive treatment for multiple sclerosis. Magnetic resonance imaging does, however, have its limits. Because of its aforementioned sensitivity, MRI may show abnormal images that resemble plaques but are not. The physician s diagnosis is, first and foremost, still a clinical matter. Magnetic resonance imaging helps with the diagnosis but does not replace the neurologist. 2) Cerebrospinal Fluid (CSF) With lumbar puncture (spinal tap), the neurologist can take a sample of the cerebrospinal fluid by inserting a needle into the back between the vertebrae. This fluid circulates through the brain and spinal cord. When analyzing this fluid, the neurologist looks for an abnormal increase in proteins, an increase in IgG, which is a form of antibody, and oligoclonal bands, which also result from abnormal production of antibodies. Although used less frequently since magnetic resonance imaging became available, lumbar puncture remains necessary for some cases where there is doubt about a diagnosis after the clinical examination and magnetic resonance imaging. 3) Evoked Potentials With this system, it is possible to evaluate the time it takes for a visual or sensory message to reach the brain. In MS, it 17

20 18 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. 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 time it takes for visual stimulation to reach your brain. The same type of test can be done for touch, you will be given small electric shocks in the hand or the leg. A slowdown in one of these areas will suggest to the physician that there are lesions at different locations than those found during the previous clinical examination. This is compatible with the principle of attack on the white matter in more than one area (space) and over time.

21 Conclusion The diagnosis of MS is often difficult at the onset of the illness, but by following the progression of the disease, it becomes easier owing to the appearance of different neurological deficiencies. The diagnosis is, above all, based on the medical history, neurological examination, and certain laboratory tests that reveal the presence of multiple lesions dispersed throughout the central nervous system. Despite the range of increasingly precise laboratory tests, the diagnosis of multiple sclerosis depends on the clinical judgment of a neurologist. Dr. J. Marc Girard is a neurologist with the Centre hospitalier de l Université de Montréal (CHUM), Hotel-Dieu Hospital, in Montreal. He has contributed his expertise to the Multiple Sclerosis Society of Canada (Quebec Division) for over 10 years. 19

22 Notes

23 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. Multiple Sclerosis Society of Canada QUEBEC DIVISION 666 Sherbrooke St. West Suite 1500 Montreal, Quebec H3A 1E7 Telephone: (514) (toll free) Fax: (514) (toll free) SPMS (7767) Web Site: To access the Multiple Sclerosis Society of Canada local chapter nearest you: Toll-free number in Canada: info@mssociety.ca Internet: This brochure has been produced with an unconditional grant from