Chronic fatigue syndrome seems to occur sometimes after a virus infection. Now, researchers have shown that some patients with the syndrome have evidence of virus in their muscles, and this in turn is linked to abnormal muscle function.
Dr. R. J. M. Lane and others at Imperial College in London, UK, looked for RNA from enteroviruses in muscle biopsies taken from 48 patients with chronic fatigue syndrome and from 29 people with normal muscles
Muscle biopsy samples from 10 of the 48 chronic fatigue patients were positive for enterovirus RNA, Lane’s team reports in the Journal of Neurology, Neurosurgery, and Psychiatry. “All 29 human tissue controls…were negative for enterovirus sequences.”
The investigators say the RNA most closely that from coxsackie B virus.
In addition, the patients with chronic fatigue syndrome went through an exercise test on the day of the biopsy, and the researchers measured the patients’ blood levels of lactic acid before and after the test.
Twenty-eight patients had an abnormal lactate response to exercise, “reflecting impaired muscle energy metabolism.” Moreover, 9 of the 10 subjects who tested positive for the presence of virus in their muscles had this abnormal response.
The team concludes that their findings support the notion that chronic fatigue syndrome has different causes, “and that some cases have a peripheral component to their fatigue related to muscle dysfunction.”
SOURCE: Journal of Neurology, Neurosurgery, and Psychiatry, October 1, 2003.