Researchers have found that the Kawasaki-like syndrome reported in some children with coronavirus is actually a new inflammatory condition.

A study led by researchers at Imperial College Academic Health Science Centre (AHSC), a joint initiative between Imperial College London and three NHS hospital trusts, has now identified the key symptoms and clinical markers of this new syndrome, which should advance its diagnosis and treatment.

The researchers studied the condition – now called Paediatric Inflammatory Multisystem Syndrome Temporally associated with SARS-CoV-2 (PIMS-TS) – in 58 children admitted to eight hospitals across England.

They found that on average it appears to affect older children than Kawasaki disease (nine years versus four years old, respectively), and that it tends to present with abdominal pains and diarrhoea alongside the common features such as fever. The research also suggests that Black and Asian patients are more susceptible.

Also of crucial importance, blood tests from these patients show different results to those with Kawasaki disease, with more markers of inflammation and cardiac enzymes, suggesting that the heart is under greater strain in those with PIMS-TS.

Kawasaki disease restricts growth of the coronary artery thus reducing the flow of blood to the heart. Doctors use immune therapy to address this issue and have also been using this treatment strategy in patients with PIMS-TS, though the researchers note that given the clear differences between the two conditions this needs further investigation.

The research team is unable to definitely conclude at this time that PIMS-TS is caused by COVID-19, but given that 45 of the 58 children been infected with the virus, it is believed likely.

Also, most of the children who exhibited signs of past infection had antibodies for novel coronavirus, which suggests that PIMS-TS develops after infection, possibly because of immune system over-drive.

“An important next step will be to review this data in the context of other studies being published from around the world. This will help inform management guidelines and to further refine the case definition,” noted Dr Alasdair Bamford, consultant and specialty lead in paediatric infectious diseases at Great Ormond Street Hospital.

The research paper Clinical Characteristics of 58 Children With a Pediatric Inflammatory Multisystem Syndrome Temporally Associated With SARS-CoV-2, by Elizabeth Whittaker et al was published in the Journal of the American Medical Association.