Multi-system inflammatory syndrome in children & adolescents (MIS-C): A systematic review of clinical features and presentation

Abstract

Multisystem Inflammatory Syndrome in Children (MIS-C) is a new phenomenon reported worldwide with temporal association with Covid-19. The objective of this paper is to evaluate reported cases in children and adolescents. From 1726 papers, 35 documented papers related to MIS-C cases identified 783 individual cases of MIS-C between March-June 2020; with 55% being male (n = 435) and a median age of 8.6 years (IQR, 7-10 years; range 3 months-20 years). Patients with MIS-C were noted to have a high frequency of gastrointestinal symptoms (71%) including abdominal pain (34%) and diarrhea (27%). Cough and respiratory distress were reported in 4.5% and 9.6% cases respectively. Blood parameters showed neutrophilia in 345/418 (83%) of cases and a high CRP in 587/626 (94%). 362/619 (59%) cases were SARS-CoV-2 infection positive (serology or PCR) however only 41% demonstrated pulmonary changes on chest imaging. Severity of illness was high with 68% cases requiring intensive care admission; 63% requiring inotropic support; 244/783 (28%) cases needing some form of respiratory support (138 mechanically ventilated), and 31 required extra-corporeal membrane oxygenation. Treatment strategies included intravenous immunoglobulin (63%) and intravenous steroids (44%). 29 cases received Infliximab, 47 received IL1 (interleukin) receptor antagonist, and 47 received IL6-receptor antagonist. 12/783 (1.5%) children died. In summary, a higher incidence of gastrointestinal symptoms were noted in MIS-C. In contrast to acute Covid-19 infection in children, MIS-C appears to be a condition of higher severity with 68% of cases having required critical care support.

Keywords: COVID-19; Critically unwell; MIS-C; Multi-system inflammatory Syndrome; PIMS-TS; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).