Introduction
In April 2020, clinical reports documented the occurrence of a multisystem inflammatory syndrome in children (MIS-C) during the COVID-19 pandemic in the United States, United Kingdom, Italy, and France. On May 14, 2020, the Centers for Disease Control and Prevention’s Health Alert Network issued a global alert for MIS-C after identifying a possible link between this critical illness in children and infection from the novel coronavirus SARS-COV-2, the virus that causes the COVID-19 disease[1]. The main manifestations of MIS-C in the setting of a severe inflammatory state include fever, diarrhea, shock, and variable presence of rash, conjunctivitis, extremity edema, and mucous membrane changes, and in some cases this can lead to the development of multi-organ failure[2]. The multi-organ failure in MIS-C is manifest by neurologic involvement, hyperferritinemia, and cardiogenic or vasoplegic shock [3]. Children with severe MIS-C cases who have either previous exposure to SARS-CoV-2 or tested positive for SARS-CoV-2 were admitted to the intensive care units for shock or acute heart dysfunction [4].
The MIS-C features share some aspects of the Kawasaki syndrome in terms of multisystem inflammation and high levels of inflammatory biomarkers. However, whereas MIS-C has been reported in individuals who are upto 21 years of age with a higher rate of cardiac involvement [3], patients with Kawasaki syndrome has been shown to occur predominantly in infants and children under 5 years old [4]. The etiology of Kawasaki disease remains unknown, with evidence suggesting that infectious agents could trigger the initiation of this disease. Multiple cases of previously healthy children who developed MIS-C syndrome were shown to be associated with a clinical or subclinical SARS-COV-2 infection. At present, it is unclear whether the SARS-COV-2 infection could ignite the inflammation cascade that causes MIS-C illness.
Whereas it was previously thought that SARS-COV-2 infection shows mild to asymptomatic disease in children and those that become infected are not susceptible to pneumonia secondary to COVID-19 infection, this view has significantly changed following the documentation of MIS-C in select cases of pediatric SARS-CoV-2 infection[5]. These findings has led to the conclusion that clearly more detailed studies are required to more precisely define the molecular aspects of the triggering factors of MIS-C during the COVID-19 pandemic.