Toronto’s Hospital for Sick Children says it has identified seven probable cases of severe acute hepatitis of unknown origin.
The research and pediatric hospital, also known as SickKids, says the mysterious cases were identified between Oct. 1, 2021 and April 30, 2022 and reported to Public Health Ontario.
“It remains to be seen whether this number represents an increase in cases of unknown origin compared to similar time periods in previous years or if any of these cases will be confirmed to be caused by a novel clinical entity,” the hospital said in an emailed statement.
SickKids said its infectious disease specialists were on the lookout for patients with liver disease symptoms that could include new onset of dark urine, pale stool and/or jaundice, which can turn the whites of eyes a distinctive yellow colour.
They also recommended a lower threshold for referral to specialist care.
Canada’s chief public health officer has said she was aware of international reports about some children suddenly displaying unexplained signs of severe hepatitis.
World Health Organization officials said last week they had reports of almost 300 probable cases in 20 countries. More than 100 possible cases have emerged among children in the United States, including five deaths.
“In Canada, we’ve contacted our pediatric hospitals — our 17 pediatric centres — to see if we can get a better understanding of what’s going on in Canada,” Dr. Theresa Tam said Friday.
Even before the pandemic, about half of all pediatric hepatitis cases that are severe would have no known cause, Tam added.
“We’re still at the investigation stage of trying to figure out whether any of these cases are indeed linked at all. There’s always been hepatitis and some severe cases of hepatitis in children pre-pandemic and one would expect post-pandemic as well,” she said.
Tam said cases that emerge in Canada are called “probable” because there’s no confirmation on the specific cause. She says experts in the United Kingdom and the United States have found cases involving adenovirus type 41 “but that may or may not be the cause or the only factor leading to hepatitis in children.”
Canada’s deputy chief public health officer added that federal officials were also working closely with the provinces and territories.
“We set up a surveillance system here in Canada and the case definition we’re using is broad and similar to the WHO. It’s, you know, really looking at all acute hepatitis cases among individuals less than 16 years of age, casting a wide net,” Dr. Howard Njoo said Friday. “We anticipate that there might be situations or cases coming forward that would meet that broad case definition.”
There are dozens of adenoviruses, many of them associated with cold-like symptoms, fever, sore throat and pink eye.
But some versions can trigger other problems, including inflammation in the stomach and intestines. Officials are exploring a link to one particular version that’s normally associated with gut inflammation.
Symptoms of hepatitis, or inflammation of the liver, also include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain and joint pain.
— With files from Laura Osman in Ottawa, and The Associated Press.
Cassandra Szklarski, The Canadian Press