Chronic Fatigue Syndrome does not appear to be a new illness. Relatively small outbreaks of similar disorders have been described in the medical literature since the 1930s. Furthermore, case reports of comparable illnesses date back several centuries, some possibly linked to bacterial, viral, or protozoal infections such as brucellosis, yellow fever, hepatitis, influenza, and malaria.
Fatigue syndromes also have been long recognized outside the setting of an infectious illness. For example, the clinical descriptions of Chronic Fatigue Syndrome and the rheumatologic disorder fibromyalgia, first described in the l9th century, overlap considerably. Chronic Fatigue Syndrome and depression also share some symptoms.
Interest in what now is called Chronic Fatigue Syndrome was renewed in the mid-1980s after several studies found slightly higher levels of antibody to Epstein-Barr virus (EBV) in patients with Chronic Fatigue Syndrome-like symptoms than in healthy individuals. Most of these patients had experienced an episode of infectious mononucleosis a few years before the onset of their new chronic, debilitating illness. As a result, for a time the Chronic Fatigue Syndrome-like illness became popularly termed "chronic EBV."
In subsequent investigations, it became clear that elevated EBV antibody titers were not diagnostic for Chronic Fatigue Syndrome: Some healthy people have high EBV titers and some people with Chronic Fatigue Syndrome do not. Currently, it is not considered useful to test for antibodies to EBV in a patient with symptoms suggestive of Chronic Fatigue Syndrome. More than 90 percent of adults in developed countries have been exposed to EBV by age 30, and moderately elevated antibody titers have not been associated with any EBV-related disease. Chronic EBV is an inappropriate label for this illness and should be abandoned.
The name "chronic fatigue syndrome," chosen because it reflects the most common symptom, was selected for the illness by a group of experts in 1988. When the International Chronic Fatigue Syndrome Study Group updated the case definition, they decided to retain this name until the discovery of a specific cause of or marker for the illness suggests a more fitting name.
Symptom complexes similar to Chronic Fatigue Syndrome also are known as epidemic neuromyasthenia, myalgic encephalomyelitis, postviral fatigue syndrome, and chronic fatigue and immune dysfunction syndrome in different parts of the world. No immune dysfunction specific to Chronic Fatigue Syndrome has been found, however, and there is no evidence linking encephalomyelitis to the pathology of the illness.
Source: National Institutes of Health.
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