Objectives Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe condition resulting in excessive response of the immune system after SARS-CoV-2 infection. We report a single-center cohort of children with MIS-C, describing the spectrum of presentation, therapies, clinical course, and short-term outcomes. Methods This is a prospective observational study from to a tertiary pediatric rheumatology center including patients (aged 1 month to 21 years) diagnosed with MIS-C between April 2020-April 2021. Demographic, clinical, laboratory results and follow-up data were collected through the electronic patient record system and analyzed. Results A total of 67 patients with MIS-C were included in the study. Fever was detected in all patients; gastrointestinal system symptoms were found in 67.2% of the patients, rash in 38.8%, conjunctivitis in 31.3%, hypotension in 26.9% myocarditis, and/or pericarditis in 22.4%, respectively. Respiratory symptoms were only in five patients (7.5%). Kawasaki Disease like presentation was found 37.3% of the patients. The mean duration of hospitalization was 11.8 7.07 days. Fifty-seven patients (85%) received intravenous immunoglobulin (IVIG), 45 (67%) received corticosteroids, 17 (25.3%) received anakinra, and one (1.5%) received tocilizumab. Seven of the patients (10.4%) underwent therapeutic plasma exchange (TPE). In 21 (31.3%) patients, a pediatric intensive care unit (PICU) was required in a median of 2 days. The first finding to improve was fever, while the first parameter to decrease was ferritin (median 6.5 days (IQR, 4–11.2 days)). Sixty-five patients were discharged home with a median duration of hospital stay of 10 days (IQR, 7–15 days). Conclusion Patients with MIS-C may have severe cardiac findings and intensive care requirements in admission and hospital follow-up. The vast majority of these findings improve with effective treatment without any sequelae until discharge and in a short time in follow-up. Although the pathogenesis and treatment plan of the disease are partially elucidated, follow-up studies are needed in terms of long-term prognosis and relapse probabilities.

Background: This study aimed to evaluate electrocardiographic and echocardiographic findings, Holter recordings of the multisystem inflammatory syndrome in children, and to identify prognostic factors for cardiac involvement. Methods: We retrospectively reviewed demographic characteristics, medical data, laboratory findings, electrocardiogram and echocardiographic findings, 24-hour Holter recordings, need for an ICU, and extracorporeal membrane oxygenation in multisystem inflammatory syndrome in children. Acute left ventricular systolic dysfunction was defined as left ventricular ejection fraction (EF) ≤%55 on echocardiography. Results: Sixty-seven children were included in the study. 24-hour Holters were recorded in 61.2% of the patients and 49.2% were normal. On echocardiographic examination, 14.9% of the patients had systolic dysfunction (EF ≤ 55%). While 32.8% of patients had mild mitral regurgitation, 3% had moderate mitral regurgitation, and 6% had mild aortic regurgitation. There was no statistically significant difference in EF values between the group with arrhythmia in Holter and the group with normal Holter results (p ≥ 0.05). B-type natriuretic peptide was positively correlated with C-reactive protein, ferritin, and fibrinogen. Significant effectivity of the B-type natriuretic peptide value was observed in the differentiation of those with EF ≤ and > 55%. Extracorporeal membrane oxygenation support was needed for three (4.5%) patients. One patient who died had systemic juvenile idiopathic arthritis. Conclusions: Neutrophil/lymphocyte ratio, C-reactive protein, D-dimer, ferritin, troponin, and B-type natriuretic peptide were found to be significantly higher in patients with systolic dysfunction. Also, the cut-off value of 1700 pg/ml for B-type natriuretic peptide was significantly effective. These parameters may indicate the severity of the disease but should be supported by prospective studies.