Patient reports of "long hauler" symptoms after COVID-19 have compelled clinicians and researchers to pay closer attention to an often-neglected medical condition that could potentially result from the virus -- postural orthostatic tachycardia syndrome (POTS).
POTS affects the autonomic nervous system, and is as too little blood flow to the heart when patients move from a seated to upright position. While "textbook cases" of POTS present as heart palpitations and lightheadedness, symptoms can include brain fog, tiredness, exercise intolerance, chronic nausea, constipation, sleep disturbance, or metabolic dysfunction.
Due to the multi-systemic nature of POTS and a lack of awareness within the medical community, the condition has been overlooked by clinicians for years. But as more and more patients present with dysautonomia after COVID-19, POTS is getting attention from both healthcare providers and researchers.
There are no large studies describing the incidence of POTS in COVID-19 patients. However, new research may help physicians identify the long haulers struggling with this illness, which many hope will benefit the POTS community as a whole.
A Tricky Diagnosis
The condition itself is not new, but the term "POTS" was coined by researchers at the Mayo Clinic just under 30 years ago. Before that, POTS was called by other names, including Da Costa's syndrome or chronic orthostatic intolerance.
Between people have been diagnosed with POTS in the U.S. While anyone can develop the condition, women ages 15 to 50 are disproportionately affected. POTS is infamously difficult to diagnose, with the average diagnostic delay at .
"The problem with POTS is that it's really ubiquitous in terms of symptoms," said Amro Stino, MD, co-director of the Autonomic Lab at the University of Michigan in Ann Arbor. Symptoms can be "head-to-toe," ranging from heart palpitations and light-headedness to chronic fatigue and brain fog.
Another reason for the delay in diagnosis for POTS is that many clinicians do not know much about it.
"There is not a lot of awareness about POTS among many medical doctors," said Tae Chung, MD, an assistant professor of physical medicine and rehabilitation at Johns Hopkins University in Baltimore who runs a POTS clinic.
Pam Taub, MD, a cardiologist at the University of California San Diego who also treats POTS patients, agreed that providers are not well-educated on how to diagnose the condition because of relatively new terminology. As a result, she said patients may be turned away by several clinicians before getting a diagnosis.
"They often go from provider to provider with a laundry list of symptoms, and often get misdiagnosed or dismissed as being crazy," Taub told 乌鸦传媒.
POTS After COVID
The pandemic is already starting to increase awareness around POTS. Since early reports of post-acute infection sequelae of SARS-CoV-2 (PASC) emerged in the media, specialists who typically saw POTS patients began to see increases in their caseloads.
"I've seen a huge surge in patients after COVID that have symptoms of POTS," Taub said.
But this surge has not come as a surprise. One of the mechanisms for POTS is post-viral infection, and cases have been documented after both Lyme disease and Epstein-Barr virus.
There are still many unknowns about how exactly POTS develops; but there are theories that it may be autoimmune in nature. After a viral infection such as COVID-19, the immune system gets confused, and it develops autoantibodies that mistake body tissue for a foreign pathogen. In the case of POTS, these autoantibodies damage the sympathetic nervous system, ultimately leading to dysfunctional blood circulation.
"This isn't shocking to anyone in the field of autonomic neurology, because we already knew that many types of dysautonomia are post-virally triggered," said Lauren Stiles, JD, POTS patient and co-founder of Dysautonomia International, a non-profit that aims to increase awareness around dysautonomia.
Viral infections are not the only thing that can lead to POTS -- surgery, concussions, pregnancy, or puberty can also trigger the condition. Clinicians typically use diagnostics such as a head-tilt test and transcranial Doppler to confirm a diagnosis.
A few case reports also strengthened the evidence for POTS developing after COVID. The documented POTS in a 26-year-old female emergency department nurse last September, describing symptoms of tachycardia and impaired autonomic function almost 6 months after the patient contracted COVID-19.
Additionally, a case series published by Madeleine Johansson, MD, PhD, of Lund University and Skåne University Hospital in Sweden, found three patients with COVID-19 that developed POTS more than 3 months after they had the virus.
"Much remains unknown about the specific mechanisms responsible for the POTS-like symptoms in post-COVID-19 patients or how long these symptoms will last, but chronic symptoms are expected in a subset of patients based on this initial clinical experience," Johansson's team said.
Treatments and Future Research
As POTS patients are unable to regulate their blood volume, the goal of treatment is improving blood flow. In Chung's clinic, he recommends a combination of increasing salt and water intake, as well as physical exercise.
"I combine dietary and medication therapy with physical therapy, because that is a very important part of our treatment," Chung said.
There is no one medication to address all symptoms for POTS patients. Chung uses midodrine, fludrocortisone, and beta-blockers, but added that these medications are used to treat symptoms and not the pathophysiology of the illness itself.
Taub recently published testing ivabradine in POTS patients. Her study found that the drug was safe and improved heart rate and quality of life in POTS patients. None of the patients included in the trial were previously infected with COVID-19.
While there are medications and treatments available, Taub said she hopes future research will improve understanding about the mechanisms. Earlier this year the NIH announced an initiative to study PASC, following Congress's allocation of more than $1 billion to support the study of long-term health complications after COVID-19. While not all PASC is POTS, researchers may be able to better understand this condition through federally funded research.
"I think what COVID has done is really brought more attention to this diagnosis," Taub said. She emphasized that she is seeing a quick recovery in many POTS patients recovering from COVID-19, and stated that while recovery times may vary, patients should remain hopeful.
"There is a lot we can do to help them," Taub added.