Cases of children with fever and multisystem inflammatory disease that appear to be temporally related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported. A recent study was undertaken to describe the clinical and laboratory characteristics of this novel syndrome and to compare these characteristics with those of other pediatric inflammatory disorders.

A total of 58 children (median age, nine years) who met the criteria for pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 and who had been hospitalized in the United Kingdom were enrolled in the study. All patients had persistent fever and variable combinations of sore throat, headache, and abdominal pain. Admission to a pediatric critical care unit was required for 29 patients. Shock requiring inotropic support occurred in 27 patients, and mechanical ventilation was needed in 25.

Results of polymerase chain reaction tests to detect SARS-CoV-2 were positive in 26% (15/58) of patients, and immunoglobulin G (IgG) antibody against SARS-CoV-2 was positive in 40 of the 46 patients tested (87%). In total, 78% (45/58) of patients had evidence of current or prior SARS-CoV-2 infection. All patients had evidence of a marked inflammatory state.

Three patterns of disease were identified in the children hospitalized for pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2. One group of children had persistent fever and elevated levels of inflammatory markers but no features of Kawasaki disease, shock, or organ failure. The second group met the diagnostic criteria for Kawasaki disease. The third had shock and clinical, echocardiographic, and laboratory evidence of myocardial injury. Compared with children who have Kawasaki disease, Kawasaki disease shock syndrome, and toxic shock, those with pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 were generally older and had different clinical and laboratory features.

This study was based on retrospective data from different hospitals and investigations that didn't follow a standardized protocol. Also, the prevalence of SARS-CoV-2 IgG positivity in the population couldn't be determined, and the cohort may have included children with Kawasaki disease rather than the newly identified condition associated with SARS-CoV-2.