Heart Rate, Blood Pressure Problems Triggered by Standing Upright In Teens With CFS

Research findings may help explain debilitating symptoms, excessive school absences

VALHALLA, NY — Researchers have found that when teenagers with chronic fatigue syndrome (CFS) stand upright, in as little as six minutes they experience orthostatic tachycardia syndrome (OTS), symptoms of which include a dramatic increase in heart rate and decrease in blood pressure, and their legs and feet can swell and turn blue.

In a new study in the August 1999 Journal of Pediatrics, Dr. Julian Stewart and colleagues at New York Medical College found that on a head-up tilt test, 92 percent of CFS patients (23 of 25) experienced OTS and the remaining eight percent (two of 25) fainted. None of the controls had OTS, although 70 percent of adolescents with a prior history of fainting and 31 percent of healthy controls fainted. In contrast to the OTS response of the CFS patients, in which standing caused the heart to race, the controls who fainted had a vasovagal response, in which both heart rate and blood pressure fell.

In addition, standing upright caused the legs and feet of CFS patients to swell and turn blue, meaning that blood was pooling in their legs, depleting the remainder of their body (most significantly the heart and brain) of oxygen. This response was seen in 80 percent of the CFS patient group, but only five percent of the fainting controls and none of the healthy controls.

The researchers also compared the CFS patients to adolescents with OTS who did not meet the U.S. Centers for Disease Control (CDC) criteria for CFS. Although they had similar heart rate and blood pressure responses to the test, the adolescents with CFS tended to respond sooner and more often have blood pooling in their legs. These may be clues to why the CFS patients were sicker than any of the other groups, missing an average of 40 percent of school days, while the OTS patients and controls only missed an average of 12 percent and five percent, respectively.

"This study helps us understand why young people with CFS have trouble standing and sitting upright, and why that makes it so difficult for them to attend school on a consistent basis," said Kimberly Kenney, Executive Director of The CFIDS Association of America. "It also provides an important clue to the pathophysiology of CFS. Additional research will determine the prevalence of this abnormality in CFS patients of all ages."

Reference:
Patterns of orthostatic intolerance: The orthostatic tachycardia syndrome and adolescent chronic fatigue. Julian M. Stewart, MD, PhD, Michael H. Gewitz, MD, Amy Weldon, Jose Munoz, MD. Journal of Pediatrics, August 1999, pages 218-225.