Severe acute respiratory syndrome coronavirus 2-related multisystem inflammatory syndrome in children mimicking Kawasaki disease

Schematic distribution of the clinical signs in multisystem inflammatory syndrome in children (MIS-C) associated with SARS-CoV-2. ▪ The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been characterized by high transmission rates and high mortality in adults with predisposing factors, including age>70 years, obesity, diabetes, systemic hypertension and other underlying diseases. During the second week of viral pneumonia, acute respiratory distress syndrome can occur and carries high mortality. Unlike most common respiratory viruses, children seem to be less susceptible to SARS-CoV-2 infection, and generally develop mild disease with low mortality. However, clusters of severe shock associated with high levels of cardiac biomarkers and unusual vasoplegia requiring inotropes, vasopressors and volume loading have recently been described. Both the clinical symptoms (i.e. high and persistent fever, gastrointestinal disorders, skin rash, conjunctival injection and dry cracked lips) and the biological signs (e.g. elevated C-reactive protein/procalcitonin and high levels of ferritinaemia) mimicked Kawasaki disease. In most cases, intravenous immunoglobin therapy improved cardiac function and led to full recovery within a few days. Adjunctive steroid therapy and sometimes biotherapy (e.g. anti-interleukin 1Ra and anti-interleukin 6 monoclonal antibodies) were often necessary. Although almost all children fully recovered within a week, some of them later developed coronary artery dilation or aneurysm. Thus, a new “multisystem inflammatory syndrome in children” related to SARS-CoV-2 has recently been described. Similarities with Kawasaki disease and the physiopathology of this syndrome still need further exploration. La pandémie due à SARS-CoV-2 est caractérisée par une haute contagiosité et une mortalité élevée chez les adultes à risque (âge supérieur à 70 ans, obésité, diabète, hypertension, autres pathologies associées). Au décours d’une pneumonie virale, peut survenir une phase hyper-inflammatoire compliquée d’une défaillance multi-viscérale avec Syndrome de Détresse Respiratoire Aiguë. Contrairement à la majorité des virus respiratoires, les enfants apparaissent moins susceptibles à SARS-CoV-2 et développent généralement une forme peu sévère, avec une faible mortalité. Cependant, des cas groupés d’états de choc associés à des biomarqueurs cardiaques élevés et à une vasoplégie inhabituelle nécessitant un traitement par inotropes, vasopres