Major medical centres across the US are trying to understand why some COVID-19 patients continue to have symptoms weeks and even months after being diagnosed.

Amy Watson, 47, is one of those patients. She’s had a fever, she says, for more than 100 days.

Watch doctors outline coronavirus symptoms in the video above

“It’s been maddening,” said Watson, a preschool teacher in Portland, Oregon.

Since mid-March, her temperature has crept up to about 37.8C almost daily by midafternoon.

Symptoms worsening

She was diagnosed with COVID-19 in April, about a month after her symptoms – cough, congestion and extreme fatigue – began.

Now, those symptoms have evolved into weeks of low-grade fever and a burning sensation under her skin.

Watson’s illness was never severe enough to warrant hospitalisation.

Instead, her symptoms have lurked in the background, never fully resolving.

Doctors have had few answers for her.

“My doctor has been very good at listening to me. She just doesn’t have a lot of ideas as far as how to fix what’s wrong,” Watson said.

But there is a growing movement among health care providers to not only listen but also figure out ways to help such patients.

“Physicians should not be discounting the experience of individuals, especially in the case of a disease that we know next to nothing about,” said David Putrino, a physical therapist and assistant professor at the Mount Sinai Health System in New York City.

“This is a very real condition,” he said.

‘New syndrome’

Last week, the World Health Organisation and the Centers for Disease Control and Prevention also acknowledged such reports and said they were working to better understand the recovery phase of the illness.

Putrino and colleagues at Mount Sinai have begun monitoring COVID-19 patients who experience a milder, long-lasting form of the virus at home.

“What we’re trying to understand is what does this new syndrome look like?” Putrino said.

“How might we manage it, and how might we help some of these people get back to a regular daily life?”

Lung complications

Dr Jessica Dine is the director of the advance consultative pulmonary division at Penn Medicine in Philadelphia.

She said she began noticing a subset of COVID-19 patients whose symptoms lingered long after their diagnoses thanks to a hospital program called COVID Watch, a texting service that does daily check-ins with COVID-19 patients at home.

Now Dine is working with those patients to better understand their illness.

Her team starts by ruling out obvious causes of the long-term symptoms.

“The first thing I do is make sure is there not something new going on, that we’re not missing something,” Dine said, such as a secondary infection, a complication of the virus or a side effect of treatment.

If Dine and her team are able to rule out other causes, they have two hypotheses for what’s going on.

The first is that it’s possible that the virus is still somewhere in the body, undetectable through testing.

The other is that the virus is gone from the body but patients are experiencing what’s referred to as post-viral inflammatory syndrome, in which the body’s immune system remains “revved up” even after the virus goes away.

“What we need is more research to explain where the symptoms are coming from,” Dine said.

One theory is that the inflammation triggered by COVID-19 damages the autonomic nervous system, which affects functions we don’t consciously think about, such as digestion, sweating, sleep, heart rate and blood pressure.

Long-lasting damage

Dr Mitchell Miglis, a neurologist at Stanford University, ascribes to this theory.

He said it appears that for some people, “the body is still damaged” even when the virus is long gone.

“It can take a really long time to fully recover,” he said, adding that it’s too soon to know whether the condition will clear up eventually or whether the symptoms will continue as a chronic disease.

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