After a 61-year-old woman developed a racing heartbeat and shortness of breath without explanation, doctors believed she had postural orthostatic tachycardia syndrome (POTS), likely as a result of a COVID-19 infection. However, it was only after doctors realized that they had skipped an "essential step" that the true cause was revealed, Lisa Sanders writes for the New York Times Magazine.

A slew of symptoms without a known cause

A 61-year-old woman began noticing that she was often out of breath. Although she initially thought her weight might be the issue, her daughter was concerned that it might be lingering effects of a COVID-19 infection that she had had a few years earlier.

Over time, the patient's symptoms continued to worsen. "One week she was so dizzy it was hard for her to walk," Sanders writes. "The next week she shared her concerns about her recent weight loss: 10 pounds in just two weeks."

Although her doctor initially suggested that she might not be drinking enough water or getting enough exercise, her symptoms did not abate.

Without a clear cause of her symptoms, the patient underwent ultrasounds, chest x-rays, echocardiograms, and wore a Holter monitor for 24 hours to track her heartbeat. She also had an MRI scan of her brain, a CT scan of her chest, and many blood tests, but none of them could explain her symptoms, leaving the patient "frustrated and frightened."

Eventually, the patient was referred to a neurologist, a cardiologist, and Yale University's Long COVID Multidisciplinary Care Center, where Sanders is the medical director.

Could the patient have POTS?

When the patient first met with Sanders, she said she was out of breath all the time and that her health had declined rapidly. However, even after extensive tests of her heart and lungs, the only abnormality was seen on the Holter monitor test, which found that her heart would sometimes beat rapidly.

Based on the patient's symptoms, Sanders believed the patient might have POTS, a condition that affects the autonomic nervous system, which regulates involuntary bodily functions such as heart rate, blood pressure, and digestion. The condition can lead to low blood volume and poor blood vessel constriction, and some symptoms include fainting, irregular heartbeats, fatigue, and more.

Although the cause of POTS is unclear, it often develops after a concussion or viral illness, such as COVID-19. According to Sanders, she regularly sees long COVID patients with POTS. A recent study also estimated that up to 14% of patients may have developed POTS after a COVID-19 infection.

To determine whether the patient had POTS, she was given an active-stand test, which monitors heart rate and blood pressure when a person is lying on their back and when they stand in place for 10 minutes.

During the test, the patient "became lightheaded and out of breath after only a few minutes, and the test had to be stopped early," Sanders writes. "Her heart rate had increased — to 140 from 101."

Although Sanders wasn't sure if all of the patient's symptoms were due to POTS, she believed treating the condition would be a good first step. The patient was told to drink more water and use compression garments to get blood from her lower extremities back to her heart. She was also later prescribed medication when her heart continued to race.

A few weeks later, the patient told Sanders that her heart rate had improved, but she was rapidly losing weight. The patient had lost 25 pounds in three months, a detail that had Sanders reconsidering her initial diagnosis.

A missing step reveals the answer

"Weight loss was not a usual symptom of POTS," Sanders writes. "… Suddenly her symptoms took on an entirely different shape."

According to Sanders, she had made assumptions about what care the patient needed since her other doctors had believed her symptoms were due to long COVID. However, none of the doctors really knew if the patient had long COVID or not, especially since there's a wide range of symptoms and no definitive way to make a diagnosis.

"[A]s with so many of the disorders for which there are no definitive tests, [long COVID] is a diagnosis that can be made only when other possibilities have been ruled out," Sanders writes. "In seeing this patient, I skipped that essential step."

Looking at the patient's symptoms again, which included a racing heart, shortness of breath without any exertion, and rapid weight loss, Sanders determined that it was "a classic presentation of thyroid-hormone overload, a condition known as hyperthyroidism."

A lab test soon confirmed the hyperthyroidism diagnosis, and the patient started taking medication to block her hormone production. In the end, the patient was ultimately diagnosed with Graves' disease, an autoimmune disorder that causes antibodies to bind to thyroid gland receptors and trigger a near continuous release of hormones.

Since starting new medications, the patient said she now feels much better, and her symptoms are no longer as severe.

"In medicine, most diagnoses are made through a process of recognition. We see something, recognize it and act on what we see. Most of the time we are right," Sanders writes. But "the first diagnosis to come to mind can never be the only one considered." (Sanders, New York Times Magazine, 6/7)