The Hospital for Sick Children in Toronto 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 mystery cases were identified between October 1, 2021 and April 30, 2022 and reported to Public Health Ontario.
Dr. Upton Allen, head of the hospital’s division of infectious diseases, said on Tuesday that large children’s hospitals like his regularly see children with severe hepatitis and that the overall numbers “appear to be pretty consistent with what that we have seen before”.
“But we’re looking at those numbers carefully in great detail,” Allen added.
World Health Organization officials said last week they had reported nearly 300 probable cases in 20 countries. More than 100 possible cases have arisen in children in the United States, including five deaths.
Allen could not say if the seven cases identified by SickKids are different from what they would have seen in previous years.
“What we can say is that we have cases that meet the World Health Organization case definition. But we are not yet able to say with certainty that these cases really represent a new signal,” he said.
SickKids said its infectious disease specialists are on the lookout for youngsters with symptoms of liver disease that may include a new appearance of dark urine, pale stools and/or jaundice, which can give the whites of the eyes a distinctive yellow color.
They also recommended a lower threshold for referral to specialist care.
Allen said confidentiality issues prevented him from releasing details of the seven cases, but the children were previously healthy and aged between less than a year and 12 years old.
He did not give details of their medical conditions or the need for a liver transplant.
“But what I can say is that severe hepatitis in general will inevitably end up requiring a transplant in some children if the hepatitis is particularly severe,” he said.
Ottawa’s pediatric health center, CHEO, said Tuesday it had no suspected cases of acute pediatric hepatitis admitted to hospital. Only one suspected case since December is counted in the number published by SickKids, a CHEO spokesperson said by email.
Vancouver’s BC Children’s Hospital also said it had not seen any cases, while a spokeswoman for Alberta Health said the province was “in the early days of work gathering information.”
Canada’s chief public health officer said federal officials are working with all 17 pediatric centers across the country to better understand what’s going on.
Even before the pandemic, about half of all cases of severe pediatric hepatitis would have no known cause, Dr. Theresa Tam said on Friday.
“We are still at the investigative stage to try to determine if any of these cases are indeed linked. There has always been hepatitis and severe cases of hepatitis in children before the pandemic and post-pandemic would be expected as well,” she said.
Tam said cases that emerge in Canada are called “probable” because there is no confirmation on the specific cause. She says experts in the UK and US have found cases involving adenovirus type 41 “but this 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 provinces and territories to launch a broad surveillance network.
“We anticipate that there may be situations or future cases that meet this broad case definition,” Dr. Howard Njoo said on Friday.
There are dozens of adenoviruses, many of which are associated with cold-like symptoms, fever, sore throat, and pink eyes.
But some versions can trigger other problems, including inflammation of the stomach and intestines. Officials are exploring a link to a particular version that’s normally associated with gut inflammation.
“The verdict is still out on whether or not the real culprit is adenovirus,” Allen said of the SickKids cases.
“Adenoviruses belong to a family of viruses that can persist in our body in certain cells for long periods of time. And it’s not unusual that if we get seriously ill and are hospitalized for a reason completely unrelated to adenovirus, it’s not unusual to be able to detect adenovirus in some people.
A case of severe hepatitis in a child would manifest as a very obvious illness, and that’s rare, Allen said.
“If your child is on leave, you should be connected to your family doctor anyway, right? But I don’t want people standing in (emergency) line because the kid started throwing up once or something,” Allen said.
Besides jaundice, dark urine and pale stools, there are several other key symptoms to watch out for, SickKids noted.
These include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, and joint pain.
— With files from Laura Osman in Ottawa and the Associated Press.
This report from The Canadian Press was first published on May 10, 2022.
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