Fatigue Syndrome News Is Promising—but Preliminary


by Guy McKhann, M.D.

November 16, 2009

One of the hardest things for a patient to deal with is uncertainty: about diagnosis, about possible outcomes, and about therapy. I tell such patients, “We are going to review the medical history, do a number of tests, some of which you have had before, and then try to make a diagnosis. You might not like our diagnosis, but at least we know what we are dealing with.”  In other words, let’s see if we can remove the uncertainty from the equation.

This strategy often works, but it has been less successful for the many patients who come to the doctor with an array of symptoms that include muscle and joint pains, difficulty concentrating and remembering, and a feeling of exhaustion, made worse by only minimal exercise. But the overwhelming symptom is persistent fatigue, not relieved by resting. Some struggle along, barely making it through the day. Others are essentially bedridden. These patients bounce around, or are bounced around, among internists, neurologists, rheumatologists, psychiatrists, physical therapists, and others. The problem is confounded by an overlapping group of descriptive names such as fibromyalgia, chronic Lyme disease, and chronic fatigue syndrome, separate diseases with many similar symptoms. Further complicating the problem is the lack of any definitive tests to establish a diagnosis.
 
In my experience, these patients can be classified in two large groups. The first comprises people who have been going through life well, without significant illness or complaints about their health. They then have an acute bout of fever and flu-like symptoms—as many people are having now. However, these people don’t get better—the feelings of fatigue, aches and pains, and just not being right persist for weeks, months or even years. We search in vain for some precipitating factor—a virus, some other infection or peculiar toxic exposure—without success.

The second group is different; there is no clear-cut start. These patients just slide into a series of symptoms that are hard to pin down. It is members of this group who try the patience of internists and are often labeled psychogenic.
 
It is in this setting that the recent report by Judy Mikovits and colleagues (covered Oct. 12 in the New York Times) has generated much interest. They found that a relatively new virus, called XMRV, is present in about two-thirds of those diagnosed with chronic fatigue syndrome, compared with only 3.7 percent of controls.  Not surprisingly, many patients who have been struggling with the uncertainty surrounding their disease are feeling quite vindicated.

Does this mean that the long-sought viral basis for chronic fatigue syndrome has finally been found? Not yet. This is a promising first step, but several further steps need to be taken, and soon. First these findings must be evaluated in other labs, which should be done in two ways: Populations of patients newly diagnosed with chronic fatigue syndrome and suitable controls need to be enrolled and tested for XMRV, and samples from the patients need to be tested in more than one laboratory in a blinded way—one in which the other labs do not know the diagnosis associated with the samples being tested.

The first approach—recruiting a second or third patient population and controls—is essential, yet difficult. The diagnosis is not clear-cut, and to the extent possible, researchers should be sure they are studying the same type of patient. I would focus on the first group I mentioned above: those who were previously healthy and start with an acute onset. In such situations it is sometimes necessary for an independent panel to review each case and decide, without knowing the viral results, whether a patient meets the diagnostic criteria.

Why so much caution? We in the scientific community have been burned before. The most striking example is multiple sclerosis where, over the years, there have been multiple reports of various viruses associated with the disease. None has held up—yet.

On the other hand, skepticism also met initial reports that a virus was the cause of a syndrome that appeared on the scene about 30 years ago: AIDS. The underlying virus, HIV, now affects millions around the world.

Keep tuned on this one.