New research from the Icahn School of Medicine at Mount Sinai has identified a link between long COVID and chronic fatigue syndrome, adding to a growing understanding of the overlap between the two illnesses.
It is estimated up to 50 percent of those diagnosed with COVID-19 will experience some kind of persistent, lingering symptoms beyond the few weeks of acute disease. Informally known as long COVID, the condition has more recently been clinically dubbed PASC (Post-Acute Sequelae of SARS-CoV-2 infection).
It is still unclear what causes long-term symptoms after COVID-19 but researchers have begun to notice distinct similarities between long COVID and chronic fatigue syndrome, which is also known as myalgic encephalomyelitis (ME/CFS). A review article published in August, led by researchers from the Johns Hopkins School of Medicine, indicted the two illnesses share similar biological abnormalities.
This new research enrolled 41 patients experiencing persistent COVID-19 symptoms between three and 15 months after their acute infection. In particular, all patients were experiencing continued shortness of breath (known as dyspnea) despite showing normal results on pulmonary function tests, chest X-rays, and CT scans.
The cohort completed a cardiopulmonary exercise test (CPET) designed to help doctors investigate the causes underlying shortness of breath. Strikingly, 88 percent of the long COVID patients displayed abnormal breathing patterns during the CPET.
“Recovery from acute COVID infection can be associated with residual organ damage,” explains Donna Mancini, lead author on the new study. “Many of these patients reported shortness of breath, and the cardiopulmonary exercise test is often used to determine its underlying cause. The CPET results demonstrate several abnormalities including reduced exercise capacity, excessive ventilatory response and abnormal breathing patterns which would impact their normal daily life activities.”
Almost all the cohort exhibited low CO2 values at rest indicating chronic hyperventilation. Mancini says this suggests the dyspnea seen in long COVID could possibly be treated by offering patients breathing exercises.
“These findings suggest that in a subgroup of long haulers, hyperventilation and/or dysfunctional breathing may underlie their symptoms,” says Mancini. “This is important as these abnormalities may be addressed with breathing exercises or ‘retraining.’”
This kind of dyspnea has previously been detected in ME/CFS patients, affirming the growing link between the two chronic illnesses. The researchers conducted diagnostic interviews with the entire long COVID cohort to assess each individual for ME/CFS. Nearly half of the cohort (46 percent) met the diagnostic criteria for ME/CFS.
The new findings make reference to prior studies highlighting ME/CFS-like symptoms in survivors of the 2003 SARS epidemic. A key 2009 study found 27 percent of SARS survivors met the diagnostic criteria for ME/CFS four years after the acute infection.
Much more work will be needed to tease out the correlations between long COVID and ME/CFS, but in the short term the new research indicates cardiopulmonary exercise testing could be a useful way to assess long COVID patients.
The new study was published in the journal JACC:Heart Failure.
Source: American College of Cardiology
