Multisystem inflammatory syndrome in children during the coronavirus disease pandemic of 2019: a review of clinical features and acute phase management

The current coronavirus disease of 2019 (COVID-19) pandemic has presented unique health challenges in the pediatric population. Compared to adults, the most significant change in viral disease manifestation is encompassed by the multisystem inflammatory syndrome in children (MIS-C). MIS-C is a new inflammatory syndrome which develops 2-4 weeks after COVID-19 exposure, with evidence suggesting it is a post-infectious immune reaction. We describe its epidemiology, pathophysiology, diagnosis (which varies based on definition used) and treatment options based on published recommendations. A systematic literature search we conducted through MEDLINE yielded 518 abstracts and identified five studies that reported more than 100 cases of MIS-C and their mortality. Most cases developed multiorgan dysfunction, including cardiovascular, dermatologic, neurological, renal, and respiratory issues, and required intensive care unit (ICU) admission. Many patients admitted to the ICU needed inotrope support and invasive mechanical ventilation, and the most severe cases required extracorporeal membrane oxygenation support. Most clinicians treated MIS-C with intravenous immunoglobulin, systemic steroids, and biological therapies. Overall mortality was low (2-3%) in all studies. Further research is needed to: understand if early intervention can prevent its progression; optimize its treatment; and improve outcomes of this new syndrome for the patients who develop MIS-C.