MONDAY, April 11, 2022 (HealthDay News) -- Older children and teens are the most vulnerable to severe cases of a rare inflammatory disorder that can occur in youngsters who've had COVID-19, a new study finds.
It included 232 children aged 18 and younger who were admitted to 15 hospitals in Canada, Costa Rica and Iran with suspected multi-system inflammatory syndrome (MIS-C) between March 1, 2020, and March 7, 2021.
The World Health Organization's definition for MIS-C includes: fever that lasts for at least three days; elevated C-reactive protein, which indicates inflammation; illness involving two or more systems with no obvious microbial cause of inflammation, and a positive COVID test or suspected contact with a positive case.
Most of the patients in the study (89%) had gastrointestinal symptoms such as pain, and skin problems like rashes and swelling (85%). Heart involvement was common (59%), as were clotting abnormalities (90%).
Of the 232 children, 73 (31.5%) were admitted to ICU, and 64% needed treatment for very low blood pressure. The risk of admission to the ICU was higher in children ages 6 to 12 years (44%) and 13 to 17 years (46%) than in children ages 5 and under (18%).
Children admitted to the hospital later in the pandemic (between November 2020 and March 2021) were more likely to be admitted to the ICU (50 of 112 or 45%) than those hospitalized earlier (23 of 120, 19%).
The researchers also found that those patients with high blood markers for inflammation had a higher risk of severe MIS-C.
The study was published April 11 in the Canadian Medical Association Journal.
Diagnosing MIS-C can be challenging, the researchers noted.
"Multi-system inflammatory syndrome in children is a new diagnosis, with differing diagnostic criteria that have not been validated," Dr. Joan Robinson, a pediatrician at the University of Alberta in Edmonton, Canada, and co-authors wrote.
"Most of these children lacked a history of contact with a person with proven SARS-CoV-2 infection. Identifying exposure can be difficult as infected contacts may be asymptomatic or may never have been tested," they said in a journal news release.
International consensus on MIS-C diagnostic criteria is needed to improve clinical care and research, the study authors stressed.
There's more on MIS-C at the U.S. Centers for Disease Control and Prevention.
SOURCE: Canadian Medical Association Journal, news release, April 11, 2022