When most people think of the new coronavirus, they imagine symptoms such as a dry cough and high fever. But new research out of China shows that a minority of cases appear with gastrointestinal symptoms only.
In about one-quarter of patients in the new study, diarrhoea and other digestive symptoms were the only symptoms seen in mild Covid-19 cases, and those patients sought medical care later than those with respiratory symptoms.
"Failure to recognise these patients early and often may lead to unwitting spread of the disease among outpatients with mild illness, who remain undiagnosed and unaware of their potential to infect others," said a team from Union Hospital and Tongji Medical College in Wuhan, China, the original epicentre of the coronavirus pandemic.
"The data in this study highlight the presence and features of this important subgroup of Covid-19 patients and should be confirmed in larger international studies," the researchers concluded.
Virus throws a curveball
One US expert agreed.
"We are only now learning the varied spectrum of symptoms for patients who present with Covid-19," said Dr Robert Glatter, an emergency medicine physician at Lenox Hill Hospital in New York City.
"This virus has thrown a curveball at us, as we now realise that gastrointestinal symptoms may be the initial signs of the disease, even without cough, fever, or difficulty breathing," he said. "The good news is that the majority of patients with gastrointestinal symptoms typically have mild disease."
In the new study, the research team tracked data from 206 patients with mild Covid-19. Nearly one-quarter (48) had digestive symptoms only, 69 displayed both digestive and respiratory symptoms, and 89 had respiratory symptoms only.
Of the patients with digestive symptoms, 67 had diarrhoea, the study found. Of those, about one in five had diarrhoea as the first symptom in the course of their illness.
Patients with digestive symptoms ill for longer
Diarrhoea lasted between one to 14 days, with an average duration of more than five days and a frequency of about four bowel movements a day.
About one-third of patients with a digestive symptom did not have a fever, the investigators found.
Patients with digestive symptoms took longer to seek medical care than those with respiratory symptoms (16 days versus 11 days), a finding that was consistent with previous research.
The new study also found that patients with digestive symptoms had a longer total time between the start of symptoms and being clear of the coronavirus, were more likely to have coronavirus in their faeces (73% versus 14%), and were ill longer than those with respiratory symptoms.
The study was recently published online in the American Journal of Gastroenterology.
Study considered 'vital'
The Chinese team stressed that of course there are many illnesses circulating in the community that can trigger gastrointestinal symptoms, "and most instances of new-onset diarrhoea, nausea, vomiting, or low appetite are not from Covid-19."
Still, "clinicians should recognise that new-onset, acute digestive symptoms in a patient with a possible Covid-19 contact should at least prompt consideration of the illness," the researchers explained.
Dr Brennan Spiegel is co-editor-in-chief of the journal. He called the study "vital because it represents the 80% or more of patients who do not have severe or critical disease. This is about the more common scenario of people in the community struggling to figure out if they might have Covid-19 because of new-onset diarrhoea, nausea, or vomiting."
"It's vital to recognise this key aspect of how the disease presents, since it can trigger the need for self-quarantine," he said.
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