Doctors are reporting a growing number of cases of a rare, life-threatening, multi-system inflammatory syndrome in children that is being linked to the new coronavirus, leaving scientists scrambling to identify and understand the condition.

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A new inflammatory syndrome threatens young Covid-19 patients around the world

Doctors in recent weeks have reported a rising number of cases of the deadly inflammatory syndrome, which currently is known as Pediatric Multi-System Inflammatory Syndrome Potentially Associated with Covid-19. The condition typically afflicts children who develop it within days or weeks after they become infected with the new coronavirus.

Doctors have reported cases among children who have tested positive for the new coronavirus and displayed respiratory symptoms commonly linked with Covid-19, the disease caused by the virus, as well as in children who tested positive for the new coronavirus or antibodies to the virus, suggesting they had been infected at some point, but who did not exhibit those respiratory symptoms. However, not every child with the syndrome has tested positive for Covid-19.

Doctors said the syndrome causes inflammation of the blood vessels, impairs organ function, and can potentially cause damage to the heart. Other symptoms include fever, skin rashes, gland swelling, abdominal pain, vomiting, and diarrhea, according to STAT News.

According to Jane Newburger, a pediatric cardiologist at Boston Children's Hospital, most children with the syndromecome into the hospital with impaired organ function and a fever, and some come in "very sick, even in shock."

So far, the cause of the condition is unknown, but some physicians believe it stems from a patient's immune system overacting to an infection, STAT News reports. Doctors say the volume of cases in Covid-19 patients implies the conditions are likely linked.

How prevalent is the syndrome?

According to the New York Times, officials have reported at least 50 cases of the condition in European countries, including Britain, France, Italy, Spain, and Switzerland. At least one child in Britain died from the condition, Reuters reports.

Providers in the United States over the past few weeks also have reported an increasing number of cases, with several cases reported in California, Louisiana, and Mississippi, the Times reports.

New York Gov. Andrew Cuomo (D) on Saturday announced that state officials are reviewing 73 cases of the syndrome, and three children in New York have died. Each of those three children tested positive either for the new coronavirus or antibodies to the virus.

"It's still a rare condition. But it's rising," said Steven Kernie, a pediatric critical care expert at NewYork-Presbyterian and Columbia University's children's hospital, which has treated up to 20 children with the syndrome.

The influx in cases are weakening doctors' previous assumptions that children are not susceptible to complications from Covid-19, Reuters reports. "Children seem to laugh off Covid-19 most of the time," Newburger said. "But rarely, a child will develop this hyper-inflammatory state."

Researchers rush to understand new inflammatory syndrome

Worldwide, research efforts are underway to learn more about the deadly inflammatory syndrome and its effects, Reuters reports.

Maria Van Kerkhove, a coronavirus expert at the World Health Organization (WHO), said WHO is asking "for the global network of clinicians to be on alert for this and to ensure that they capture information on children systematically so that we can … improve our understanding and guide treatment."

In addition, CDC said it is working with the Council of State and Territorial Epidemiologists to gather data on the syndrome and develop a case definition that would allow the agency to better track the condition.

In New York, state officials are requesting that hospitals perform testing for the new coronavirus and its antibodies on every patient with the inflammatory disorder. Officials also have partnered with the New York Genome Center and the Rockefeller University to determine whether some children are genetically predisposed to developing the syndrome.

Sean O'Leary, a pediatric infectious disease expert at Children's Hospital Colorado who also serves on the American Academy of Pediatrics' committee on infectious disease, said, "Every academic center I know of is looking for these cases and trying to systematically track them."

But in the meantime, physicians are treating children with the syndrome with antibiotics, high-dose aspirin, intravenous immunoglobulin, steroids, supportive oxygen through the nose, and, in some severe cases, ventilators. Physicians also are raising concerns that there could be undiscovered long-term effects of the life-threatening condition.

"It's a very scary illness," Eric Topol, a cardiologist and director of the Scripps Research Translational Institute said (Steenhuysen, Reuters, 5/7; Layne, Reuters, 5/9; Joseph, STAT News, 5/5; Jacobs/Sandoval, New York Times, 5/9).