“Characteristics of children with multisystem inflammatory syndrome in children during different COVID-19 waves “Single centre Study”

Multisystem inflammatory syndrome in children (MIS-C) has been identified as a systemic inflammatory disorder complicating Coronavirus Disease 2019 (COVID-19) in children. Three different definition criteria have been proposed including clinical and laboratory features. MIS-C has variable presentation, severity and outcome. This study aimed to describe the clinic-laboratory and imaging features of MIS-C among Egyptian pediatric patients, as well as the treatment and outcome. This was a retrospective observational study that included 142 MIS-C patients who were admitted at Children’s Hospital, Ain Shams University during the period from June 8, 2020, to January 26, 2022. Diagnosis of MIS-C followed CDC criteria. The medical records of the patients were reviewed for age, gender, initial presentation, interval time since COVID-19 infection or contact with COVID-19 patient, course of the disease, blood picture, acute phase reactants, kidney and liver function tests, imaging studies mainly echocardiogram and magnetic resonance imaging of the brain, therapeutic lines and outcome). The median age varied from 4.5 years (4th wave) to 9 years (2nd wave). PCR positivity declined from 61% (1st wave) to 0% (4th wave), with lower IgG and higher IgM levels in the 1st wave (p < 0.001). Fever was universal (100%), Gastrointestinal symptoms were more common in the 1st wave (p = 0.005), whereas respiratory and neurological symptoms rose in later waves (p < 0.05). Lymphopenia and thrombocytopenia varied across waves (p < 0.01), with elevated inflammatory markers consistent throughout. Cardiac involvement, particularly coronary abnormalities, was highest in the 1st wave (p = 0.005). Treatment included IVIG and steroids, with increased use of pulse steroids and anti-IL1 therapy in later waves (p = 0.001). Hospital stays shortened from 10 days (2nd wave) to 3.5 days (4th wave), and mortality was highest in the 1st wave (9.4%). Conclusion: MIS-C cases in our center showed a consistent 2–7 weeks lag after COVID-19 peaks, with variable clinical and treatment trends. Improved outcomes over time, including shorter hospital stays and lower mortality.