The puzzling picture of multiple sclerosis

FDA Consumer, July-August, 1989 by Margie Patlak

THE PUZZLING PICTURE OF MULTIPLE SCLEROSIS

Neal Schmidtke of Waukesha, Wis., used to keep in shape by bounding up stairs two at a time and running to his appointments. But in January of 1987, when he was 31, Schmidtke started tiring quickly and feeling weak in the knees. By summer, clumsiness replaced his athletic prowess when he started having numbness in his hands and feet and frequent muscle twitches. Soon he could no longer shave or even stand in the shower. After blacking out a few times in August, Schmidtke embarked on a medical odyssey through four months of tests adding up to $20,000 in doctor bills and a near-certain diagnosis of multiple sclerosis.

Each year, 8,000 Americans are told they have multiple sclerosis, a debilitating ailment whose cause and cure are unknown. Even diagnosing multiple sclerosis is difficult and fraught with uncertainties. Symptoms vary greatly among patients and, over time, even within a single individual. This variability stems from the very nature of the disease.

The symptoms of multiple sclerosis are due to patchy destruction of the fatty sheath, called myelin, that envelops and insulates the nerves in the brain and spinal column. Scar tissue forms wherever the myelin jacket is lost, causing a hardening, or "sclerosis." The scar tissue slows or blocks the passage of messages along these nerves, which govern body movements and permit sensations of temperature and pain, among others. Because different nerves service different parts of the body, symptoms of multiple sclerosis vary according to which nerves have myelin destruction. A patient whose sclerosis is mainly limited to the nerves controlling the limbs, for example, will have numbness and, in extreme cases, paralysis of the extremities, whereas another patient may suffer more from vision problems because the optic nerves are affected.

Some common symptoms of multiple sclerosis are weakness, tingling, numbness, loss of coordination and balance, dizziness, fatigue, impotence, muscle spasms, slurred speech, burning or painful sensations, and blind spots in the center of vision. Blurred or double vision is often the first sign of the disease; a common late symptoms is loss of bowel and bladder control. Patients are spared any mental disabilities, except in rare instances.

Usually symptoms come and go mysteriously. Attacks (the occurrence or worsening of symptoms) are considered by many doctors to be a sign of myelin destruction, while remissions (cessation or lessening of symptoms) are thought by some doctors to signify myelin repair, although this remains to be proven.

Most patients initially have a series of attacks followed by periods of complete or partial recovery. As years go by, the attacks become more frequent and there is less improvement during remissions until, in the late stages of disease, patients usually experience a progressive decline with no remissions.

Multiple sclerosis is rarely fatal; however, the average life expectancy of a patient is 93 percent of that of the general population. Nor is the disease always disabling; 1 out of 5 patients only has one attack, with little to no progression thereafter. Studies show that two-thirds of patients are still able to walk with or without the assistance of walking aids 25 years after their disease was diagnosed. Of those, at least half can engage in most of the activities they performed before developing the disorder for as long as 15 to 20 years after its onset. In a small percentage of patients, the disease progresses very rapidly and leads to premature death from disease complications such as pneumonia and other infections.

Tricky to Diagnose

Most of the nearly 500,000 American men and women diagnosed with multiple sclerosis first get symptoms between the ages of 20 and 50. Diagnosis is difficult and often slow because so many neurologic and other disorders cause some of the same symptoms seen with multiple sclerosis. A person who is having trouble in only one part of the central nervous system, for example, often has to undergo special X-ray tests to rule out other causes, particularly tumors and strokes.

Unsuspected patches of myelin destruction are sometimes detected in sensory evoked potential tests. These painless tests use electrodes attached to the skin to measure how quickly nerve messages travel from the eye, ear or skin to the brain.

Magnetic resonance imaging (MRI) can also locate demyelinated areas in the brain and spinal cord. The patient lies still for about a half hour in a large doughnut-shaped magnet, while the tissues are pulsed with radio waves. Radio signals emitted by diseased tissue differ from those of healthy tissue.

Spinal taps--in which a small sample of spinal fluid is drawn for analysis--are often done to measure the levels of certain anti-bodies and cells that are usually elevated in patients with multiple sclerosis.

The sporadic nature of the disease also makes it difficult to diagnose. For example, a person may have vision problems typical of multiple sclerosis, but not have the disease. Most such people never experience the problem more than once. Those with recurrences usually have multiple sclerosis, but another episode of vision disturbance may not surface for months or even years after the first. Often multiple sclerosis cannot be firmly diagnosed until a person has had at least two episodes of dysfunction involving more than one area of the central nervous system that cannot be otherwise explained.