COVID-19 and Hyperinflammatory Syndrome in Children: Kawasaki Disease with Macrophage Activation Syndrome in Disguise?

Loomba, Rohit S; Villarreal, Enrique G; Flores, Saul

A hyperinflammatory syndrome has been described in times of COVID-19 in children. In the setting of uncertainty due to a new virus, the so-called hyperinflammatory syndrome has been coined as a novel entity by some and is being referred to as pediatric inflammatory multisystem syndrome (PIMS). However, the characteristics of the syndrome resemble those of Kawasaki disease (KD), an inflammatory syndrome in children that can lead to coronary artery abnormalities due to a subsequent vasculitis. Furthermore, Kawasaki disease may occasionally trigger macrophage activation syndrome (MAS), a condition in which there is uncontrolled activation and proliferation of macrophages and other cell types, and could lead to multiorgan system dysfunction. This study provides a review of the data regarding COVID-19, Kawasaki disease, and macrophage activation syndrome to demonstrate the similarities and differences between the inflammatory syndrome seen with COVID-19 and KD. In addition, a framework for diagnosis and evaluation is provided that focuses on the pathway previously established for KD and MAS. The authors believe that based on current knowledge, KD treatment delays may carry deleterious effects in the near future for children with COVID-19-related Kawasaki disease.