Recent Experience: Corticosteroids as a First-line Therapy in Children With Multisystem Inflammatory Syndrome and COVID-19-related Myocardial Damage.

Background: Cardiovascular complications with myocarditis in multisystem inflammatory syndrome in children (MIS-C) associated with severe acute respiratory syndrome coronavirus 2 infection have been reported, but the optimal therapeutic strategy remains unknown.

Methods: A retrospective cohort study included 19 patients with acute left ventricular systolic dysfunction associated with MIS-C, average years of age 13.2 ± 3.8, treated from April 2020 to April 2021.

Results: Treatment failure (TF) was observed in 8 patients (in the intravenous immunoglobulin [IVIG] group 7/10; in the corticosteroid [CS] group 1/9). The independent risk factor for TF was IVIG treatment (odds ratio [OR] 18.6, 95% confidence interval [CI] 1.6-222.93, P = 0.02). Patients initially treated with CS became afebrile during in-hospital day 1 (1.5, interquartile range [IQR] 1-2), while IVIG-treated patients became afebrile on in-hospital day 4 (IQR 2-4.25), after CS was added. The C-reactive protein (CRP) significantly declined in CS-treated patients on day 2 (P = 0.01), while in the IVIG group, CRP decreased significantly on the fourth day (P = 0.04). Sodium and albumin levels were higher on third in-hospital day in the CS group than in the IVIG group (P = 0.015, P = 0.03). A significant improvement and normalization of ejection fraction (EF) during the first 3 days was observed only in the CS group (P = 0.005). ICU stays were shorter in the CS group (4, IQR 2-5.5) than in the IVIG group (IVIG group 7, IQR 6-8.5) (P = 0.002).

Conclusions: Among children with MIS-C with cardiovascular involvement, treatment with CS was associated with faster normalization of LV EF, fever, laboratory analysis, and shorter ICU than IVIG-treated patients.