Identification of Multisystem Inflammatory Syndrome in Children Classes and Development of Hyperinflammation Score in Pediatric COVID-19.

The aim of this study is to describe characteristics and hospital course of children admitted with COVID-19 to a tertiary care pediatric center in Southeastern United States, and to present the frequency of three classes of multisystem inflammatory syndrome in children (MIS-C) and develop pediatric COVID-19 associated hyperinflammation score (PcHIS). A retrospective cohort study of 68 children was performed. Critical illness was defined as any child requiring respiratory or cardiovascular support or renal replacement therapy. PcHIS was developed by using six variables: fever, hematological dysfunction, coagulopathy, hepatic injury, macrophage activation, and cytokinemia. Centers for Disease Control and Prevention criteria were used to identify MIS-C, and three classes of MIS-C were identified based on the findings of recently published latent class analysis (Class 1: MIS-C without Kawasaki like disease, Class 2: MIS-C with respiratory disease, and Class 3: MIS-C with Kawasaki like disease). The median age was 6.4 years. Fever, respiratory, and gastrointestinal were common presenting symptoms. MIS-C was present in 32 (47%), critical COVID-19 illness in 11 (16%), and 17 (25%) were admitted to the PICU. Children with critical illness were adolescents with elevated body mass index and premorbid conditions. PcHIS score of 3 had a sensitivity of 100% and a specificity of 77% for predicting critical COVID-19 illness. Among MIS-C patients, 15 (47%) were in Class 1, 8 (25%) were in Class 2, and 9 (28%) were in Class 3. We conclude that most children with COVID-19 have mild-to-moderate illness. Critical COVID-19 is mainly seen in obese adolescents with premorbid conditions. Three Classes of MIS-C are identifiable based on clinical features. Validation and clinical implication of inflammation score in pediatric COVID-19 need further investigation.