Abstract

Multisystem inflammatory syndrome in children (MIS-C) is a serious condition that appears to be linked to coronavirus disease 2019 (COVID-19). Most children who become infected with the COVID-19 virus have only a mild illness. But in children who go on to develop MIS-C, some organs, and tissues — such as the heart, lungs, blood vessels, kidneys, digestive system, brain, skin, or eyes — become severely inflamed. Signs and symptoms depend on which areas of the body are affected. MIS-C is considered a syndrome — a group of signs and symptoms, not a disease — because much is unknown about it, including its cause and risk factors. Identifying and studying more children who have MIS-C may help to eventually find a cause. The CDC issued a Health Advisory on May 14, 2020, that outlines the following case definition for MIS-C: • An individual aged <21 years presenting with fever, laboratory evidence of inflammation, and evidence of clinically severe illness requiring hospitalization, with multisystem (≥2) organ involvement (cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic, or neurological); AND • No alternative plausible diagnoses; AND • Positive for current or recent SARS-CoV-2 (COVID-19) infection by RT-PCR, serology, or antigen test; or COVID-19 exposure within the 4 weeks prior to the onset of symptoms. Signs and symptoms include persistent fever, inflammation (based on laboratory test results), and evidence of organ dysfunction or shock. Although different presentations have been described, common symptoms include: • Kawasaki disease-like features • Toxic shock syndrome-like features with hemodynamic instability. • Cytokine storm/macrophage activation or hyperinflammatory features. • Thrombosis, poor heart function, diarrhea and gastrointestinal symptoms, acute kidney injury. • Shortness of breath suggestive of congestive heart failure. Respiratory symptoms typically reported in adults with COVID-19 may not be present in pediatric patients with MIS-C. Management strategy varied from one institute to other but common medications are currently in use including IVIG, Steroid and immunosuppressive medications. Patients who are hospitalized with suspected MIS-C should be considered patients under investigation for COVID-19. RT-PCR and antibody testing for COVID-19 (if available) should be performed. Patients diagnosed with MIS-C should have close outpatient pediatric cardiology follow-up starting 2 to 3 weeks after discharge. Patients diagnosed with myocarditis should have cardiology directed restriction and/or release for vigorous activities.