Heart Disease in Children: Inflammatory Syndromes.

Kawasaki disease is an acute vasculitis of unknown etiology that primarily affects children younger than 5 years, although it can affect older children. Cardiac complications are the major cause of morbidity and mortality in Kawasaki disease and can include myocarditis. Long-term sequelae include coronary artery dilation. Treatment is high-dose intravenous immunoglobulin and aspirin. Multisystem inflammatory syndrome in children (MIS-C) is a severe hyperinflammatory syndrome associated with COVID-19 disease. It shares clinical characteristics with Kawasaki disease but causes hyperinflammation and often results in cardiac dysfunction. Treatment for MIS-C is intravenous immunoglobulin and glucocorticoids. Myocarditis is inflammation of the myocardium and pericardium and has multiple causes. It is associated with COVID-19 infection and mRNA COVID-19 vaccines. The incidence and clinical significance of these associations remain uncertain and are a current topic of research and debate.