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A study published on June 3, 1997 in the American Journal of Medicine found that autonomic nervous system dysfunction is present in many patients with Chronic Fatigue Syndrome. 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 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. Freeman, who is also the director of the Autonomic and Peripheral Nerve Laboratory at Beth Israel Deaconess and Anthony L. Komaroff, MD, Division of General Medicine, Brigham and Women's Hospital, wrote the study, "Does Chronic Fatigue Syndrome involve the Autonomic Nervous System?"
In 23 CFS patients they studied, the Boston Investigators found prominent features of autonmic dysfunction, and abnormalities in tests of autonomic function, including the tendency toward low blood pressure during what is known as the tile table test, patients were asked to lie on a table angled at between 60 degrees. Some individuals felt dizzy and fainted or almost fainted, syas Freeman. The investigators also noted that many 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, analagous to the experience of patients with the mysterious Guillain-Barre syndrome in which the myelin sheath that covers the nerve is damaged. As with CFS, 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 rescent 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 CFS. 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 CFS 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 medication, says Freeman.
SOURCE: Beth Israel Deaconess Medical Center.
This article reprinted with permission from the Summer 1997 issue of Medical Professionals/Persons With CFIDS (MPWC NEWS) Newsletter. Lori L. Clovis -- Editor.
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