Clinical and Laboratory Characteristics of the Multisystem Inflammatory Syndrome in Children: A Case Series of 75 Patients

Background: SARS-CoV-2 has been characterized since December 2019 as the etiology of severe pneumonia throughout the world. However, the majority of children and adolescents with the respective infection have mild COVID-19. In April 2020, a warning was issued by the National Health Service (NHS), based on which a multisystem inflammatory syndrome in children (MIS-C) could be associated with COVID-19, presenting with cardiovascular shock, fever, and hyperinflammation. The syndrome presents with fever and organ involvement but with no pathognomonic findings or diagnostic tests, while some of the manifestations are almost the same as those of Kawasaki disease. Objectives: Knowledge of clinical course, demographic data, treatment, and prognosis can contribute to the more efficient management of the patients and, consequently, a decrease in morbidity and mortality. Methods: Seventy-five patients < 18 years from September 22, 2020, to March 10, 2021, in Namazi hospital, Shiraz, Iran, with a diagnosis as per MIS-C defined criteria, were recruited. Results: Median age of the patients was 6.2 years, and 58.6% were male. Of the patients, 46% had positive SARS-CoV-2 RT-PCR, antibody, or both. Thirty percent of the total patients reported contact with proven COVID-19 cases. The abdominal free fluid in 17 patients, hepatitis in one patient, and stasis in both kidneys of one patient were detected. Upon echocardiography on the first day, 77%, 48%, 21%, and one patient were with tricuspid regurgitation, mitral regurgitation, abnormal LV function, and myocarditis, respectively; however, after 5 - 7 days, the repeated echocardiography revealed 44% of patients with tricuspid regurgitation, 30% with mitral regurgitation, and 6% with abnormal LV function. For the treatment, 18% of the patients received inotropes, 60% ASA, 32% IVIG, 84% glucocorticoids, and 25.3% received furosemide. All of the patients received antibiotics as well. Finally, 97% of the patients were discharged alive, while two cases died. Conclusions: The results of this study suggest the importance of cardiac consultation along with early hospital care during the course of MIS-C in order to prevent the associated short-term and long-term complications.