COVID or stomach flu? Why it’s hard to know now


If you’ve recently felt green around your gills or heard more stomach-ache stories than usual, you may have wondered if Omicron or its subvariant, BA.2, is causing an increase in gastrointestinal problems.

Some clinicians have also reported seeing more COVID-19 patients suffering from gastrointestinal symptoms in recent weeks.

But medical experts say there are a few possible explanations — and it’s not necessarily due to the strains of COVID-19 currently circulating in Canada. Diarrhea, vomiting and abdominal pain have been recognized as common symptoms of COVID-19 since the start of the pandemicwhile nausea, reflux, heartburn, loss of appetite and weight loss are also recognized as potential symptoms.

Dr. Sumon Chakrabarti, an infectious disease specialist in Mississauga, Ont., said he recently saw a higher proportion of patients with COVID-19 whose main symptoms are gastrointestinal.

“I’ve seen people who just show up with vomiting,” he said.

But, he adds, it’s not that Omicron necessarily causes more gastrointestinal problems, but rather that it is now easier to detect COVID-19 in these patients than at the start of the pandemic. .

“We’re testing people who come in sick enough to be admitted, and also, people are doing rapid home tests with any type of symptom, so it could also be possible that we’re taking them just because we’re looking for them.”

Chakrabarti’s hypothesis is supported by data from the British company ZOE COVID Symptom Study Appby which millions of people reported their symptoms during the pandemic.

Some people with COVID experience gastrointestinal symptoms, such as diarrhea and vomiting. However, norovirus and other gastro-related illnesses are also circulating. In this photo, a shopper in Burbank, Calif., buys toilet paper amid a pandemic-fueled shortage, November 19, 2020. (Robyn Beck/AFP/Getty Images)

Based on these user reports, there is no evidence that Omicron causes an increase in gastrointestinal symptoms, said lead researcher Tim Spector, professor of genetic epidemiology at King’s College London.

“It seems to be pretty stable. We’re not seeing any major changes in symptoms. It’s still an upper respiratory infection,” he told CBC News.

Pediatricians see concerning symptoms in children

However, some pediatricians say they have seen a marked increase in the number of COVID-19 patients with gastrointestinal symptoms during the Omicron wave – and some of these symptoms are of particular concern.

Dr. Ana Sant’Anna, a pediatric gastroenterologist at the Montreal Children’s Hospital, said she had recently seen young patients with blood in their stools or vomiting, and some had suffered tears in the gastrointestinal tract at following their vomiting.

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“We haven’t seen these [symptoms] before,” Sant’Anna said, adding that none of those patients with severe gastrointestinal symptoms had respiratory symptoms while in hospital.

Despite the severity of their symptoms, nearly all of the young COVID patients bounced back quickly after treatment, she said.

“They go away in a few days, maybe a few weeks, and they go away [out] as good as new.”

Other gastro-infections on the rise

Besides COVID-19, there is another reason why more Canadians may be experiencing unpleasant gut symptoms right now.

Stomach bugs, like norovirus, are circulating more and more as life returns to normal, Chakrabarti said, with children often getting infected with gastro-like illnesses at school and then infecting their families. .

Several regions of Canada are experiencing an increase in norovirus cases. One of the main risk factors is that children are infected at school and then infect their families. In this image, children leave school in Toronto on April 6, 2021, after schools were closed due to COVID-19. (Evan Mitsui/CBC)

Symptoms of norovirus can include diarrhea, vomiting, nausea, and stomach cramps.

Recent clusters of this disease in New Brunswick have affected schools, daycare centers and long-term care homes, while hundreds of people in British Columbia, Alberta, Saskatchewan and Ontario have fallen ill after eating raw oysters.

Children are particularly at risk of dehydration from diarrhea and vomiting, whether due to COVID-19 or another gastrointestinal illness, and should be closely monitored for signs such as decreased urination, Sant’Anna said.

It’s important to keep them hydrated, and over-the-counter medications can help control vomiting. However, if children cannot retain fluids due to continuous vomiting, they may need hospital treatment with intravenous fluids, she said.

And – as is known at this stage of the pandemic – hand washing is an important precaution to prevent the spread of disease.

Can COVID-19 cause long-term gut damage?

There are limited but growing evidence people with long-lasting gastrointestinal problems, months after a COVID-19 infection, including indigestion and post-infectious irritable bowel syndrome (SIC).

A recent pre-printed study by US researcherswhich has yet to be peer-reviewed, speculated that the virus could disrupt gut bacteria and potentially contribute to long COVID.

Other infections, including viruses, bacteria, and parasites, can disrupt intestinal motility — the contractions of muscles to push food through the digestive tract — which can lead to IBS and other conditions.

Dr. Gil Kaplan, a gastroenterologist and epidemiologist at the University of Calgary, said it’s also possible that some people have had existing, but undiagnosed gastrointestinal issues that have been exacerbated by COVID-19. .

Doctors say hand washing is an important habit to maintain to prevent the spread of disease. In this photo, people line up to use portable toilets in Montreal on May 5, 2021. (Jean-Claude Taliana/CBC/Radio-Canada)

He is part of a team studying the impact of COVID-19 on people with Crohn’s disease and ulcerative colitis, known collectively as inflammatory bowel disease.

“It’s not surprising to me that we’re starting to see things like irritable bowel and other types of COVID-related conditions, which have probably been linked to other infections in the past, but we haven’t just not studied [those infections] as broadly as we have with COVID,” Kaplan said.

It’s important for people with ongoing gastrointestinal symptoms to speak to a doctor for diagnosis and treatment, he said.

So far, the children don’t appear to be suffering from long-term gastrointestinal issues as a result of their COVID-19 infections, Sant’Anna said — although that may change in the future.

“We might see that a bit later than the adults, because in terms of timing, the kids just have it now, so we [haven’t had] it’s time to have the post-IBS symptoms.”