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| |  Autonomic Nervous System Dysfunction Linked To Chronic Fatigue BOSTON, June 3, 1997 -- A study published in the current issue of the American Journal of Medicine (AJM) found that autonomic nervous system dysfunction is present in many patients with chronic fatigue syndrome (CFS). This may be explained in part by a postviral autonomic neuropathy (damage to the autonomic nervous system), cardiovascular deconditioning, or both, say the researchers. They also found that psychiatric illness was not responsible for autonomic test abnormalities. Led by lead author and neurologist Roy Freeman, MD, of Beth Israel Deaconess Medical Center and Harvard Medical School, the study determined that in CFS patients damage to the autonomic or involuntary nervous system interferes with the body's ability to regulate blood pressure, resulting in hypotension, or low blood pressure. Symptoms of chronic fatigue include fatigue, malaise following physical activity, depression, musculoskeletal pain, headaches and sore throat. Some patients experience tenderness in their lymph nodes, difficulty concentrating or falling asleep. One in 1000 American adults aged 18 and older may suffer from the illness. The cause is unknown and the syndrome is difficult to diagnose, says Freeman, who is also the director of the Autonomic and Peripheral Nerve Laboratory at Beth Israel Deaconess. In the 23 CFS patient they studied, the Boston investigators found prominent features of autonomic dysfunction, and abnormalities in tests of autonomic function, including the tendency toward low blood pressure during what is known as the tilt table test. During this test, patients were asked to lie on a table angled at between 60 degrees. Some individuals felt dizzy and fainted or almost fainted, says Freeman. The investigators also noted that many CFS patients had a rapid heart rate, or tachycardia, particularly on standing. It is well recognized that rapid heart rate occurs in response to low blood pressure or hypotension and may induce fainting. Freeman says that autonomic neuropathy may be an immune-mediated phenomenon in which the nerves are damaged trying to fight off an invading virus, analogous to the experience of patients with the mysterious Guillain-Barre syndrome in which the myelin sheath that covers the nerves is damaged. As with chronic fatigue, the cause of Guillain-Barre is also unknown, although it may result from a viral infection. The new AJM study builds on the results of two recent studies of CFS patients, in which researchers at Johns Hopkins University demonstrated that CFS patients fainted when placed on a tilt table, suggesting that hypotension might cause the fatigue and other symptoms in chronic fatigue syndrome. According to Freeman, this made the Harvard researchers wonder what the autonomic reasons for this might be. "Our findings are important to some patients with chronic fatigue because it explains why they might faint on the tilt table, why they might experience debilitating fatigue, and how they can improve certain aspects of their condition through a program of gradual exercise and medication," says Freeman. The study was co-authored by Anthony L. Komaroff, MD, Division of General Medicine, Brigham and Women's Hospital. Beth Israel Deaconess Medical Center is a major clinical, teaching, and research affiliate of Harvard Medical School.
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