Multisystem inflammatory disorder in children (MIS-C) is a recently identified rare disease process seen in some children after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. As a new disease entity, there have been efforts to clarify the diagnostic criteria for MIS-C to most accurately identify patients with this disease, while differentiating them from those with severe acute coronavirus disease 2019 (COVID-19). In this study, the researchers aimed to compare the clinical characteristics and outcomes of children and adolescents with MIS-C and those with severe COVID-19 to better distinguish between these disease states.
In this case series, 1116 patients were included who were ≤21 years of age hospitalized between March and October 2020 from 66 hospitals across 31 states. A total of 539 of these patients had MIS-C, and 577 patients had severe acute COVID-19. The Centers for Disease Control and Prevention definition for MIS-C was used in this study, which includes children <21 years old, fevers >38°C for >24 hours, clinically severe illness of ≥2 organs (multisystem involvement), no other plausible diagnosis, and evidence of current or recent SARS-CoV-2 infection or recent exposure. Severe acute COVID-19 was defined by clinical consensus criteria, including a positive reverse-transcriptase polymerase chain reaction test for SARS-CoV-2 and severe involvement of ≥1 organ systems.
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