Before COVID-19, postural orthostatic tachycardia syndrome (POTS) was one of those diseases that many people, including physicians, dismissed.
Dr. Pam R. Taub
“They thought it was just anxious, crazy young women,” said Pam R. Taub, MD, who runs the cardiac rehabilitation program at the University of California, San Diego.
The cryptic autonomic condition was estimated to affect 1-3 million Americans before the pandemic hit. Now case reports confirm that it is a manifestation of postacute sequelae of SARS-CoV-2 infection (PASC), or so-called long-haul COVID-19.
“I’m excited that this condition that has been so often the ugly stepchild of both cardiology and neurology is getting some attention,” said Dr. Taub. She said she is hopeful that the National Institutes of Health’s commitment to PASC research will benefit patients affected by the cardiovascular dysautonomia characterized by orthostatic intolerance in the absence of orthostatic hypotension.
Postinfection POTS is not exclusive to SARS-CoV-2. It has been reported after Lyme disease and Epstein-Barr virus infections, for example. One theory is that some of the antibodies generated against the virus cross react and damage the autonomic nervous system, which regulates heart rate and blood pressure, Dr. Taub explained.
It is not known whether COVID-19 is more likely to trigger POTS than are other infections or whether the rise in cases merely reflects the fact that more than 115 million people worldwide have been infected with the novel coronavirus.
Medscape
Low blood volume, dysregulation of the autonomic nervous system, and autoimmunity may all play a role in POTS, perhaps leading to distinct subtypes, according to a State of the Science document from the NIH; the National Heart, Lung, and Blood Institute; and the National Institute of Neurological Disorders and Stroke.
In Dr. Taub’s experience, “The truth is that patients actually have a mix of the subtypes.”
Kamal Shouman, MD, an autonomic neurologist at Mayo Clinic, Rochester, Minn., said in an interview that he has seen patients present with post–COVID-19 POTS in “all flavors,” including “neuropathic POTS, which is thought of as the classic postinfectious phenomenon.”
Dr. Kamal Shouman
Why does it mostly affect athletic women?
The condition, which can be the result of dehydration or prolonged bed rest, leading to deconditioning, affects women disproportionately.
According to Manesh Patel, MD, if a patient with POTS who is not a young woman is presented on medical rounds, the response is, “Tell me again why you think this patient has POTS.”
Mitchel L. Zoler/MDedge News
Dr. Manesh Patel
Dr. Patel, chief of the division of cardiology at Duke University, Durham, N.C., has a theory for why many of the women who have POTS are athletes or are highly active: They likely have an underlying predisposition, compounded by a smaller body volume, leaving less margin for error. “If they decondition and lose 500 cc’s, it makes a bigger difference to them than, say, a 300-pound offensive lineman,” Dr. Patel explained.
That hypothesis makes sense to Dr. Taub, who added, “There are just some people metabolically that are more hyperadrenergic,” and it may be that “all their activity really helps tone down that sympathetic output,” but the infection affects these regulatory processes, and deconditioning disrupts things further.
Women also have more autoimmune disorders than do men. The driving force of the dysregulation of the autonomic nervous system is thought to be “immune mediated; we think it’s triggered by a response to a virus,” she said.
Dr. Shouman said the underlying susceptibility may predispose toward orthostatic intolerance. For example, patients will tell him, “Well, many years ago, I was prone to fainting.” He emphasized that POTS is not exclusive to women – he sees men with POTS, and one of the three recent case reports of post–COVID-19 POTS involved a 37-year-old man. So far, the male POTS patients that Dr. Patel has encountered have been deconditioned athletes.