Background Multisystem inflammatory syndrome in children (MIS‐C) associated with coronavirus disease 2019 has been increasingly recognized. However, the clinical features of MIS‐C and the differences from Kawasaki disease remain unknown. The study aims to investigate the epidemiology and clinical course of MIS‐C. Methods PubMed and EMBASE were searched through August 30, 2020. Observational studies describing MIS‐C were included. Data regarding demographic features, clinical symptoms, laboratory, echocardiography and radiology findings, treatments, and outcomes were extracted. Study‐specific estimates were combined using one‐group meta‐analysis in a random‐effects model. Results A total of 27 studies were identified including 917 MIS‐C patients. The mean age was 9.3 (95% confidence interval [CI], 8.4–10.1). The pooled proportions of Hispanic and Black cases were 34.6% (95% CI, 28.3–40.9) and 31.5% (95% CI, 24.8–38.1), respectively. The common manifestations were gastrointestinal symptoms (87.3%; 95% CI, 82.9–91.6) and cardiovascular involvement such as myocardial dysfunction (55.3%; 95% CI, 42.4–68.2), coronary artery aneurysms (21.7%; 95% CI, 12.8–30.1) and shock (65.8%; 95% CI, 51.1–80.4), with marked elevated inflammatory and cardiac markers. The majority of patients received intravenous immunoglobulin (81.0%; 95% CI, 75.0–86.9), aspirin (67.3%; 95% CI, 48.8–85.7), and corticosteroids (63.6%; 95% CI, 53.4–73.8) with a variety of anti‐inflammatory agents. Although myocardial dysfunction improved in 55.1% (95% CI, 33.4–76.8) at discharge, the rate of extracorporeal membrane oxygenation use was 6.3% (95% CI, 2.8–9.8) and the mortality was 1.9% (95% CI, 1.0–2.8). Conclusion Our findings suggest that MIS‐C leads to multiple organ failure, including gastrointestinal manifestations, myocardial dysfunction and coronary abnormalities, and has distinct features from Kawasaki disease.

Background: Multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19 has been increasingly recognized. However, the clinical features of MIS-C and the differences from Kawasaki disease remain unknown. The study aims to investigate the epidemiology and clinical course of MIS-C. Methods: PubMed and EMBASE were searched through August 30, 2020. Observational studies describing MIS-C were included. Data regarding demographic features, clinical symptoms, laboratory, echocardiography and radiology findings, treatments, and outcomes were extracted. Study-specific estimates were combined using one-group meta-analysis in a random-effects model. Results: A total of 27 studies were identified including 917 MIS-C patients. The mean age was 9.3 (95% confidence interval [CI], 8.4-10.1). The pooled proportions of Hispanic and Black cases were 34.6% (95% CI, 28.3-40.9) and 31.5% (95% CI, 24.8-38.1), respectively. The common manifestations were gastrointestinal symptoms (87.3%; 95% CI, 82.9-91.6) and cardiovascular involvement such as myocardial dysfunction (55.3%; 95% CI, 42.4-68.2), coronary artery aneurysms (21.7%; 95% CI, 12.8-30.1) and shock (65.8%; 95% CI, 51.1-80.4), with marked elevated inflammatory and cardiac markers. The majority of patients received intravenous immunoglobulin (81.0%; 95% CI, 75.0-86.9), aspirin (67.3%; 95% CI, 48.8-85.7), and corticosteroids (63.6%; 95% CI, 53.4-73.8) with a variety of anti-inflammatory agents. Although myocardial dysfunction improved in 55.1% (95% CI, 33.4-76.8) at discharge, the rate of extracorporeal membrane oxygenation use was 6.3% (95% CI, 2.8-9.8) and the mortality was 1.9% (95% CI, 1.0-2.8). Conclusion: Our findings suggest that MIS-C leads to multiple organ failure, including gastrointestinal manifestations, myocardial dysfunction and coronary abnormalities, and has distinct features from Kawasaki disease.

OBJECTIVES: The indication, complications, and outcomes of extracorporeal membrane oxygenation (ECMO) in children with COVID-19–related illnesses remain unelucidated. Our study aimed to investigate the characteristics and outcomes of ECMO in children with COVID-19–related illnesses. DATA SOURCES: We searched PubMed and EMBASE databases in March 2022. STUDY SELECTION: We retrieved all studies involving children (age ≤ 18 yr) with COVID-19–related illnesses who received ECMO. DATA EXTRACTION: Two authors independently extracted data and assessed the risk of bias. Mortality, successful weaning rate, and complications while on ECMO were synthesized by a one-group meta-analysis using a random-effect model. Meta-regression was performed to explore the risk factors for mortality. DATA SYNTHESIS: We included 18 observational studies, four case series, and 22 case reports involving 110 children with COVID-19–related illnesses receiving ECMO. The median age was 8 years (range, 10 d to 18 yr), and the median body mass index was 21.4 kg/m 2 (range, 12.3–56.0 kg/m 2 ). The most common comorbidities were obesity (11% [7/63]) and congenital heart disease (11% [7/63]), whereas 48% (30/63) were previously healthy. The most common indications for ECMO were multisystem inflammatory syndrome in children (52% [47/90]) and severe acute respiratory distress syndrome (40% [36/90]). Seventy-one percent (56/79) received venoarterial-ECMO. The median ECMO runtime was 6 days (range, 3–51 d) for venoarterial ECMO and 11 days (range, 3–71 d) for venovenous ECMO. The mortality was 26.6% (95% CI, 15.9–40.9), and the successful weaning rate was 77.0% (95% CI, 55.4–90.1). Complications were seen in 37.0% (95% CI, 23.1–53.5) while on ECMO, including stroke, acute kidney injury, pulmonary edema, and thromboembolism. Corticosteroids and IV immunoglobulin therapies were associated with lower mortality. CONCLUSIONS: The mortality of children on ECMO for COVID-19 was relatively low. This invasive treatment can be considered as a treatment option for critically ill children with COVID-19.