| The principal dilemma in current management of | | | | diagnostic process. In usual descending order of |
| multiple sclerosis is that while early diagnosis enables | | | | importance they are the clinical evaluation, magnetic |
| damage-sparing treatment to begin, diagnosing MS too | | | | resonance imaging (MRI) scanning and examination of |
| early increases the likelihood of treating people who | | | | the cerebrospinal fluid. Each of these is important in its |
| don't actually have the disease. Current | | | | own way, but one component almost never stands on |
| disease-modifying drugs are all given by injection and | | | | its own merits, requiring one or both of the other |
| cost about $14,000 per year. Apart from being | | | | components for corroboration. |
| inconvenient and expensive, there is some risk of harm | | | | The clinical evaluation refers to the time-honored |
| from them which, if the patient doesn't actually have | | | | process in which the physician elicits the history of the |
| MS, occurs without any offsetting benefit. | | | | symptoms and performs a physical examination. The |
| The dilemma would not be great if multiple sclerosis | | | | physical examination consists mainly of the neurological |
| was easy to diagnose, but unfortunately MS is among | | | | examination, which is a battery of mini-tests that |
| the most difficult diagnoses in all of medicine to make, | | | | inventories the performance of different components |
| at least while still in its early stages. Early in the course | | | | of the nervous system. |
| of symptoms, MS can resemble other conditions; | | | | Even a test as high-tech and powerful as the MRI |
| moreover, other conditions can resemble MS. | | | | scan can lead to diagnostic errors. False-positives |
| Affecting 2.5 million people worldwide and 350,000 | | | | often occur when a patient has a scan for a totally |
| people in the U.S. alone, multiple sclerosis is not exactly | | | | unrelated reason--like headaches, for example--and |
| a rare disease. It affects women at least twice as | | | | has pockets of increased signal within the brain for |
| often as men and begins early in adulthood with most | | | | which the radiologist raises the possibility of multiple |
| cases starting between the ages of 20 and 40. | | | | sclerosis. When the abnormal scan leads to |
| MS is a so-called autoimmune disease, meaning that a | | | | consultation with a neurologist, the neurologist often |
| person's immune system--ordinarily useful and essential | | | | determines that multiple sclerosis is out of the question, |
| in fighting off infections--becomes overactive and | | | | and the areas of increased signal are either benign or |
| attacks the individual's own bodily tissues. Rheumatoid | | | | due to another problem entirely. MRIs less frequently |
| arthritis is another example of an autoimmune disease, | | | | produce false-negatives for multiple sclerosis, but even |
| but in MS the immune attack is not directed against | | | | so, this imaging test is believed to show just the tip of |
| joints as it is in rheumatoid arthritis. Instead, the immune | | | | the iceberg in this disease, failing to demonstrate |
| system attacks large clusters of nerve-fibers generally | | | | important changes that occur at the microscopic level. |
| deep within the central nervous system which includes | | | | Examining the cerebrospinal fluid (CSF) is another |
| the brain and spinal cord. | | | | valuable tool in diagnosing MS. The CSF bathes the |
| These attacks can produce a wide variety of | | | | inside and the outside of the brain and the outside of |
| symptoms depending on what the usual function was | | | | the spinal cord, so its cellular and chemical composition |
| of the nerve-fibers that are under attack. When the | | | | often reflects what's going on within those structures. |
| attacked nerve-fibers have to do with vision, the | | | | CSF is obtained by means of lumbar puncture, also |
| symptoms are visual, like loss of visual clarity or even | | | | known as spinal tap, a safe procedure in which a |
| doubling of vision. When the nerve-fibers are involved | | | | needle is inserted through the lower back and into the |
| with the process of bodily sensation, then the | | | | CSF space. The fluid is collected as it drips out the |
| symptoms can be numbness or tingling. In fact, visual | | | | back of the needle. In cases of active MS there are |
| or sensory symptoms are the most common initial | | | | usually abnormal proteins produced by the immune |
| symptoms in multiple sclerosis. But initial symptoms | | | | system that can be detected and measured in the |
| might instead consist of dizziness, weakness, | | | | CSF. However, here too there are false-positives and |
| clumsiness or difficulty with urination. The sheer | | | | false-negatives, so that some people with abnormal |
| diversity of early symptoms that can be due to multiple | | | | proteins don't have MS and other people with normal |
| sclerosis is one of the chief difficulties in recognizing it | | | | proteins still do have the disease. |
| for what it is and properly diagnosing it. | | | | So the diagnostic process--including clinical evaluation, |
| It's useful in this regard to consider the twin issues of | | | | MRI scanning and CSF examination--is fraught with the |
| "false-positives" and "false-negatives." In short, every | | | | possibility of error at each step of the way. Yet there |
| medical test and every diagnosis is subject to these | | | | is considerable incentive to make the diagnosis as |
| errors. False-positive means that a test or a doctor | | | | early in the disease as possible (which is also when |
| indicates that a disease is present when it is, in fact, | | | | the risk of diagnostic errors is greatest) in order to |
| absent. A false-negative error occurs when a test or | | | | initiate treatment that tames the out-of-control immune |
| a doctor indicates that a disease is absent when it is, in | | | | system. Sifting through the diagnostic information to |
| fact, present. Despite the increased confidence that | | | | make a timely and accurate diagnosis almost always |
| expanding medical knowledge and ever-more | | | | requires the assistance of a neurologist, and even with |
| sophisticated tests provide, false-positives and | | | | the help of these specialists in disorders of the |
| false-negatives are a fact of life and still apply to | | | | nervous system, sometimes the diagnosis gets revised |
| every test and every diagnosis. | | | | as time passes and clues become more definite. |
| In multiple sclerosis there are three cornerstones to the | | | | |