Why this long COVID patient developed blue legs

The patient in the case report was a 33-year-old man who had COVID-19 twice. One infection had been confirmed by a PCR test while the other was a suspected infection that occurred six months after.

For a year after his infections, the patient experienced post-exertional exhaustion, muscular pain, sleep disturbances, visual difficulties, sexual dysfunction, and brain fog. He was subsequently diagnosed with long COVID, as well as a diagnosis of postural orthostatic tachycardia syndrome (POTS) a few months later.

POTS is 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, including COVID-19. According to health experts, there may be at least 1 million or more new POTS patients due to COVID-19.

Later, the patient sought help for another symptom that had emerged. For six months, the patients' legs would become heavier and feel tingly and itchy whenever he would stand for a few minutes. They would also become blue or "dusky" in color, and a petechial rash would sometimes appear on his feet. It was only after the patient laid down that his symptoms would go away and his legs would return to their normal color.

When he was examined by doctors, they found that his heartbeat was 68 beats per minute and blood pressure was 138/85 mm Hg when laying down. However, when he stood for eight minutes, his pulse increased to 127 beats per minute. His blood pressure remained stable at 125/97 mm HG.

Based on the patient's symptoms and their examination, the doctors diagnosed the patient with "dysautonomia secondary to SARS-CoV-2 infection and associated with long COVID."

According to the doctors, the patient's leg discoloration was caused by acrocyanosis, or venous pooling and cutaneous ischemia. To prevent the discoloration, they recommended the patient increase his fluid and salt intake and exercise to strengthen his muscles.

"[C]linicians may not be aware of the link between acrocyanosis and long COVID," said Manoj Sivan, a doctor from the Leeds Institute of Rheumatic and Musculoskeletal Medicine at the University of Leeds who examined the patient. "We need to ensure that there is more awareness of dysautonomia in long COVID so that clinicians have the tools they need to manage patients appropriately."

Commentary

According to Bruce Hirsch, an infectious disease physician at Northwell Health, the patient's symptom of blue legs "doesn't seem that different from what we've been hearing over the last couple of years, like COVID toes ... and we know that the circulation is impacted in many people with the complications of long COVID."

"As part of long COVID, many people will have a disrupted autonomic nervous system," Hirsch said. "The autonomic nervous system controls blood pressure, heart rate; it's constantly adjusting the tone in our blood vessels. And for reasons that we do not know, some people with long COVID, their autonomic nervous system is completely disrupted and they're unable to maintain the tone in their blood vessels."

Separately, Amesh Adalja, an infectious disease physician at the Johns Hopkins Center for Health Security, said the patient is an "isolated case report that illustrates that POTS is part of the milieu of post-COVID syndromes."

"The significance is to raise awareness of POTS -- which is one of the only well-defined post-COVID syndrome[s] -- rather than the rare POTS manifestation of acrocyanosis," Adalja added. "Long COVID is a nebulous term and likely lumps together several disparate conditions under this label."

Going forward, "[w]e need more awareness about dysautonomia in long-term conditions; more effective assessment and management approaches, and further research into the syndrome," Sivan said. "This will enable both patients and clinicians to better manage these conditions." (Sourcheray, CIDRAP, 8/14; Fiore, MedPage Today, 8/15; Ifetkhar/Sivan, The Lancet, 8/12)

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