Diagnosis ... the whole story.
Herewith is an update and an expansion of information on the diagnostic process so that at least some of the confusion that may accompany it can be eliminated. Establishing a diagnosis of MS is step #1 in dealing with the disease.
What has remained the same is the basic criteria for diagnosis: Two attacks at least one month apart, clinical evidence of two separate lesions, and no other explanation for the symptoms. Because of the particular nature of MS, in the past, the diagnostic process could take a long time-something that was often a tremendous source of frustration for both patients and their physicians. The biggest single change that has occurred since the Summer 85 article is found in the initials MRI.
When that article was written, MRIs (magnetic resonance imaging) were still few and far between, available only in a handful of medical centers in the country. Today these machines are found in almost every major hospital in the United States. Moreover, increasingly efficient use is being made of them.
The criteria for diagnosis may now include two attacks at least one month apart, clinical evidence of at least one lesion, and paraclinical (or laboratory) evidence of one other separate lesion. The paraclinical (or laboratory) tests may include neuroimaging, with MRI or CT scanning, evoked potential studies, or CSF analysis. This change in criteria often makes a difference in the time needed for a diagnosis.
MRI is currently the preferred method for imaging the brain to detect the presence of scarring caused by MS. It uses computers and a strong magnetic field to produce pictures of the brain. It differs from CT scanning (computerized axial tomography) in that it does not use ionizing radiation X-rays) and it is many times more sensitive to the presence of plaques in the brain than CT. Often, brains that appear to be normal on CT scans will be shown to have plaques revealed on MRI. However, although the use of MRI has influenced the time factor in diagnosis of MS, it is important to understand that MS can never be diagnosed solely on the result of an MRI. There are other diseases that can cause lesions in the brain that look like those of MS. Also, sometimes spots on an MRI, UBOS" or "unidentified bright objects," are found in healthy individuals, particularly in older persons, and are not related to an ongoing disease process. Conversely, a normal MRI does not absolutely rule out a diagnosis of MS. About 5% of patients who are confirmed to have MS on the basis of other criteria do not show lesions in the brain on MRI. (It is not yet known why this is so.)
The important fact is that a diagnosis of MS still begins in the neurologist's office. Typically, it starts with a medical history and a clinical neurological examination. If these examinations reveal "classic" histories, symptoms and signs, a diagnosis often can be established without any further testing. All the diagnostic criteria have been met. However, if the picture is more complex, the paraclinical tests are indicated. Let's take a run through the usual diagnostic process and see what happens:
You've experienced some unusual symptoms-often a variety of them-that have taken you to your physician. For most people these symptoms are subtle. Transient blurred vision, numbness in an arm or leg, or unusual fatigue, for example. Others may show more acute signs: a sudden loss of vision or double vision, bladder incontinence, or possibly an overwhelming weakness causing difficulty walking. Depending on available specialists in your geographic area, your regular doctor would most likely refer you to a neurologist. (In areas where a neurologist is not available your family physician will begin the necessary process.)
The neurologist's first step will be to obtain a complete medical history. He or she will want to know about symptoms that might have occurred in any of your body systems, and how often you've experienced them.
These symptoms can include tingling sensations, numbness, slurred speech, blurred or double vision, muscle weakness or a change in bladder and bowel habits among others.
Your physician will also want to know if your symptoms have followed a relapsing-remitting pattern; that is, have you had symptoms for 24 hours or more and then have they subsided leaving you feeling "back to normal" or perhaps only with a mild residual symptom? (This is the most common course MS follows.) He will probably also inquire about any symptom-seven mild ones-experienced years before, that you might remember.
The history will also include questions about other past medical illnesses or operations, family history, and personal habits such as smoking or use of drugs.
After the medical history comes the clinical neurological examination. This covers an extensive range of functions: one group includes mental, emotional, and language functions; the other includes movement and coordination, vision, balance and sensation. Most have different tests, some so brief and simple that you may hardly recognize what you're doing as being part of a test. For instance, your general appearance and behavior will be automatically observed as the medical history is being taken, as will your levels of alertness and responsiveness. A brief assessment of mental function will often be made, for example, by asking for repetition of a series of numbers forward and backward, or simple calculations. Orientation is tested by asking a few simple questions about dates, places, or current events. The examiner will ascertain your emotional status during conversation, noting whether your thought content is clear, whether you are easily distracted, or whether there is any evidence of confusion or fluctuations in mood.
Your doctor will also assess very specifically the 12 pairs of cranial nerves in your body. You may be interested to know what they are and what they do:
I Olfactory-sense of smell II. Optic -Vision _____ III. Oculomotor ~ IV. Trochlear ~ Muscles for eye movements ~-- movements VI. Abducens ~ movements ~ _____~ V. Trigeminal-Face and scalp sensation and chewing VII. Facial-Facial muscles and sense of taste VIII. Acoustic-Hearing and equilibrium _____ IX. Glossopharynge ~ Swallowing, X. Vagus ~-- gag reflex _____~ XI. Accessory-Muscles of neck XII. Hypoglossal-Movement of tongue
These nerves are all evaluated fairly easily. For example, the examiner might ask you to follow the movement of his or her finger, listen to a tuning fork, or perform certain facial movements such as smiling or sticking out your tongue and saying "aah."
The cerebellum, that area of your brain that controls balance and coordination, will be checked, perhaps by your being asked to touch your nose with eyes opened and then closed or to walk in a straight line - heel to toe. Gait problems and position sense can also be evaluated this way. Motor function may be evaluated by gently pulling or stretching certain muscles to examine for abnormalities in tone, such as spasticity or rigidity. Muscle strength may be tested by observation of a variety of movements and ability to resist an opposing movement by the examiner. The sensory system is examined to assess the ability to feel different sensations such as pain, temperature, vibration and position.
One of the aims is to find out whether the source of any abnormalities found are in the central nervous system or in the peripheral nerves. Areas of the skin are checked by stroking them with a wisp of cotton, for instance. Pain sensations are checked by the application of light pressure with a sharp object like a pin.
Finally, your reflexes will be tested, with a reflex hammer. You are probably all familiar with one of the tests, the "Babinski reflex" in which the sole of the foot is stroked. The reaction can be an important indicator of damage to the nerves which control movement, something that occurs commonly in MS.
None of these neurological tests is painful. In fact, they are interesting, patients report. Although in general each test is short, the whole process including obtaining a thorough history, can take up to two hours. Sometimes symptoms and signs produced by examination can be so clear to the examiner that it is often unnecessary to order any further tests to confirm the diagnosis of MS. But many times, results of the neurologic examination are not so clear-cut and further supportive testing becomes necessary.
These are the paraclinical tests. Of the paraclinical tests, the MRI which we've already talked about, and the evoked potential group of electrical diagnostic studies are the most widely used. Whereas the MRI can precisely locate lesions, which may or may not be MS, EPS may show that there is a slowing of messages in the various parts of the nervous system. The two tests complement each other and can help provide a more certain diagnosis of MS. Some or all of the following might be ordered: visual evoked potentials (VEP); brainstem auditory evoked potentials (BAEP); and/or somatosensory evoked potentials (SSEP).
For these studies, electrodes are placed on the scalp, and the body systems being tested are stimulated in various ways so that the electrical reaction produced in the central nervous system can be recorded. For example, a checkerboard screen is viewed for the VEP test. Alterations in the pattern trigger responses in the brain that produce the needed recordings for evaluation. Such a test takes about 20 minutes to perform and there is no risk or discomfort. These harmless, neurophysiologic studies are valuable because they often provide evidence of plaques along the visual, auditory, or sensory pathways that are not apparent on neurologic examination.
If there is still a question about the diagnosis, and your physician feels that the support of other tests is needed, he may ask you to have a cerebrospinal fluid (CSF) examination and some blood tests. While there is no blood test for MS, often blood tests will be ordered to rule out other causes for neurologic symptoms. Some of the other conditions that may give rise to symptoms similar to those seen in MS are Lyme disease, a group of diseases known as collagen-vascular diseases, certain rare hereditary disorders and AIDS. These tests are used much less frequently than they used to be. One other factor must be mentioned when talking about diagnosis, and that is the physicians themselves. If MRI has shortened the level of time needed for diagnosis, so has the enormous spread of knowledge about MS in the medical community. In a few cases people present symptoms that are still very difficult for the physician to interpret, and even with sophisticated technology, one must simply "wait and see." But by and large diagnosis can now move along with enough speed and certainty so that at least step #1 is no longer a frustrating, frightening trial.
By Margaret Calvano, MSLS, MSIS
Director, Information Resource Center, NMSS
With Barbara Giesser, MD Assistant Professor,
Department Neurology, Albert Einstein College of Medicine
...Preparing for an MRI for an MRI MRI is painless and requires no physical preparation (such as fasting) but it can be intimidating if you aren't prepared for it. It is helpful and reassuring to know what to expect.
When you arrive for the scan, metallic objects and credit cards are removed because of the magnetic field. You will also be asked if you have a metal implant in your body. You will be given a hospital gown and you may be asked to pass through a metallic detection device similar to those used at airport security checkpoints. Then you will be placed on the scanner bed, which is rolled into a short tunnel within the center of the scanner's magnet. During the scan, you can breathe normally but must lie perfectly still. You will be able to hear and talk with a technician during the entire procedure. There are no unwanted physical side effects to be concerned about. Psychologically, however, it's worth being prepared for the following:
* You will have to hold still for a long period of time, often 30-60 minutes with brief breaks.
* You may experience some discomfort from lying on a hard surface for that length of time.
* You may experience some claustrophobia from lying inside the machine.
* As a matter of fact, if you know you're inclined to suffer from claustrophobia (or from tremors) you may want to ask for a tranquilizer or some other medication before the scan.
* Be prepared for a banging noise which goes on during the scan. It can throw you off at first.
Efforts will be made to make you feel comfortable and relaxed - if you make your needs known. Some people report that they asked for and received earphones to listen to music.
A small pillow could be requested to reduce back discomfort. Very often a buzzer is provided to push if you need to go to the bathroom. Most important, remember the technician is always there for you to talk to. Most patients report that although "MRIs are no picnic, they're really not uncomfortable," drawing on your patience quota rather than your pain quota.
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|Title Annotation:||multiple sclerosis|
|Date:||Jun 22, 1991|
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