Multiple Sclerosis : Diagnosing, Highly Variable

by Food and Drug Administration (FDA)

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Diagnosing MS

MS is "notoriously difficult to diagnose," says Reingold. There is no single test to detect it.

Until recently, to meet the diagnostic criteria for MS, a person must have had two separate attacks at least a month apart and in different parts of the body. But early on in the disease process, some people have infrequent relapses or symptoms so mild that they might not recognize a second attack, says Walton.

In Ferko's case, her eye doctor told her "not to worry about it" after her first symptom, optic neuritis, cleared up. Five years later, another doctor diagnosed her second symptom, leg numbness, as a pinched nerve.

Recent advances in technology, particularly magnetic resonance imaging (MRI), a non-invasive form of taking pictures of the brain to detect MS lesions, have aided physicians in diagnosing people with MS. "Now patients can come in with a single clinical episode and a neurologist can use an assortment of lab tools, including MRI, to determine more rapidly than waiting for a second clinical attack if there is a second lesion in the brain or spinal cord," says Reingold.

"This has led to people being given the diagnosis sooner than otherwise," says Walton. "We may now be making diagnoses of MS in more people with the least severe forms. In addition, it is possible that by treating patients earlier, the course of their disease may be less severe."

Highly Variable

One of the frustrations for newly diagnosed patients is the uncertainty of living with a potentially debilitating disease. Dennis Bourdette, M.D., chairman of the neurology department at Oregon Health & Science University in Portland, Ore., describes MS as "highly variable." "In the first few years of the condition, we don't have any way of confidently identifying individuals who may have a benign course and who will have a more active course."

"There is a series of clues that can help guide us in understanding more about what might happen," says Reingold, "but the variability of the disease from person to person makes giving an individual prognosis for multiple sclerosis very, very uncertain. Most physicians still are uncomfortable with sitting down with a newly diagnosed individual and saying we believe that this may be what is going to be the course of your disease over the next 20 to 30 years."

Relapses also are variable. When they strike, how long they last, and what organs or functions they affect differ from person to person.

"Nobody really knows why relapses occur," says McDermott. In some people, they seem to be triggered by certain events that cause trauma to the body, she says, such as an accident, surgery, viral infection, or other illness.

Temperature changes may trigger a worsening of symptoms in some individuals. This effect is usually reversible when the temperature returns to normal, but it can sometimes be confused for a clinical relapse. Some people are sensitive to heat, says Reingold, but others are more sensitive to cold. "You need to learn what your disease is like for you, and then you'll learn to cope with it."

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.