[Clinical analysis of 11 cases multisystem inflammatory syndrome associated with SARS-CoV-2 Omicron variant infection in children].

Objective: To explore the clinical characteristics, diagnosis, treatment, and follow-up of multisystem inflammatory syndrome in children (MIS-C) related to SARS-CoV-2 Omicron variant infection. Methods: A retrospective analysis was conducted on clinical data of 11 children with MIS-C, who were admitted to the Department of Pediatrics of Peking University First Hospital from December 2022 to January 2023. Clinical characteristics, treatment, and follow-up of MIS-C were summarized in this study. Results: The 11 cases contained 7 boys and 4 girls, with an age of 4.4 (2.0, 5.5) years on admission. All the patients had fever, with a duration of 7(5, 9) days. Other clinical manifestations included rash in 7 cases, conjunctival hyperemia in 5 cases, red lips and raspberry tongue in 3 cases, lymphadenopathy in 3 cases, and swollen fingers and toes in 2 cases. There were 8 cases of digestive symptoms, 8 cases of respiratory symptoms, and 3 cases of nervous system symptoms. Eight patients had multi-system injuries, and one of them had shock presentation. All 11 patients were infected with SARS-CoV-2 Omicron BF.7 variant. The laboratory examination results showed that all cases had elevated inflammatory indicators, abnormal coagulation function and myocardial damage. Six patients had elevated white blood cell counts, 5 cases had liver function abnormalities, 3 cases had kidney function abnormalities, and 8 cases had coronary artery involvement. All 11 patients received anti-infection treatment, of which 3 cases received only 2 g/kg intravenous immunoglobulin (IVIG), while the remaining 8 cases received a combination of IVIG and 2 mg/(kg·d) methylprednisolone. Among the 8 cases with coronary artery disease, 6 cases received low molecular weight heparin anticoagulation therapy. All patients were followed up in 2 weeks after being discharged, and their inflammatory markers had returned to normal by that time. The 8 cases with coronary artery disease and 3 cases with pneumonia showed significant improvement or back to normal at the 4-week follow-up. All patients had no new complications or comorbidities during follow-up of more than 3 months. Conclusions: MIS-C may present with Kawasaki disease-like symptoms, with or without gastrointestinal, neurological, or respiratory symptoms. Elevated inflammatory markers, abnormal coagulation function, and cardiac injury contribute to the diagnosis of MIS-C. IVIG and methylprednisolone were the primary treatments for MIS-C, and a favorable short-term prognosis was observed during a follow-up period of more than 3 months.