A review of 36 published studies on COVID-19 that include thousands of patients found that nearly one in five infected individuals may only show gastrointestinal symptoms during their battle with coronavirus, such as loss of appetite, nausea, vomiting, diarrhea and stomach pain.
The number of people affected by these symptoms is likely an underestimate, the researchers say, because of under-reporting early in the pandemic before doctors knew what to look for.
Researchers from the University of Alberta in Canada say their analysis of published literature since the beginning of the pandemic through July 15 serves as a reminder for physicians and the public alike to treat these symptoms as potential signs of COVID-19.
“Seeing these things is not necessarily telling us a patient has COVID-19,” study co-author Dr. Mitch Wilson, a radiologist and clinical lecturer in the University of Alberta’s faculty of medicine and dentistry, said in a news release posted Nov. 3.
“It could be from a variety of potential causes. But one of those potential causes is infection from the virus, and in an environment where COVID-19 is very prevalent, it’s something to consider and potentially raise as a possibility to the referring physician,” Wilson added.
Doctors and scientists know the most common symptoms of COVID-19 are fever, cough, fatigue and labored breathing, but more evidence continues to surface that point to gastrointestinal issues, as well as cognitive and cardiovascular problems, as additional signs of a coronavirus infection.
Of the 36 studies reviewed, one May paper found that more than 50% of 204 coronavirus patients in China reported digestive problems such as diarrhea, vomiting and abdominal pain.
Another study published in May of 4,234 U.S. COVID-19 patients revealed that about 18% of them had gastrointestinal symptoms.
In all, the review shows that 18% of patients included in the 36 studies presented these symptoms along with some other, more common ones. Meanwhile, 16% of COVID-19 cases had only gastrointestinal symptoms and nothing else.
Abdominal CT scans have shown inflammation in the small and large bowels, colons filled with fluid, cysts on bowel walls and abdominal swelling in patients with these symptoms, according to the study.
The researchers say these signs are rare and could indicate advanced disease, but radiologists should “remain vigilant” while imaging patients suspected to have COVID-19.
The study was published in September in the journal Abdominal Radiology.