Are Kawasaki Disease and Pediatric Multi-Inflammatory Syndrome Two Distinct Entities? Results from a Multicenter Survey During SARS-CoV-2 Epidemic in Italy

Background: There is mounting evidence on the existence of a childhood multi-inflammatory syndrome related to SARS-CoV-2, sharing similarities with Kawasaki Disease (KD).  Methods: On April 24th,2020 the Rheumatology Study Group of the Italian Pediatric Society launched a survey to enroll patients diagnosed with KD or KD-like disease. Classification was: 1) classical and incomplete KD, named Kawasaki Disease Group (KDG); 2) KD-like multi-inflammatory syndrome, named KawaCOVID Group (KCG). Demographic, clinical, and laboratory data, treatment information, and patients’ outcome were collected in an online anonymized database (RedCAPO). Chi square test or exact Fisher test and non parametric Wilcoxon Mann-Whitney test were used to study differences between two groups. Findings: One-hundred-forty-nine patients were recruited (96 KDG and 53 KCG). KCG children significantly differed for older age at onset and more frequent occurrence of mucocutaneous manifestations, irritability, gastrointestinal and respiratory symptoms, oxygen supplementation and ventilation, ICU recovery, and secondary Hemophagocytic Lymphohistiocytosis. Myocarditis was more common in KCG, while coronary artery abnormalities were more common in the KDG.  23/149 patients showed heart abnormalities at follow-up. KDG characteristics were compared to a historic cohort of 505 KD: no significant difference was found. Interpretation: KCG and KDG patients significantly differed in clinical manifestations and heart outcome. KDG children did not differ from a historic cohort of KD. Our data would suggest that SARS-CoV-2 infection may be linked to two inflammatory conditions in children: the classic KD, possibly triggered by SARS-CoV-2, and the multisystem inflammatory syndrome, that has already been referred as PIMS-TS or MIS-C. More data, on larger series with prospective analysis are warranted to define the best treatment and long-term outcome. Funding: The research was conducted with no funding. Declaration of Interests: AR has received grant support and/or speaking or consultant fees from AbbVie, Angelini, Bristol-Myers Squibb, Novartis, Pfizer, Reckitt-Benkiser, Roche and Johnson & Johnson; MC, SDP, FZ, CB, LV, AM, RS, RC, GZ, MF, DM, AM, AC, RMD, MCM, FLT, AM, GS, AV, RC and AT do not have any conflict of interest to declare. Ethics Approval Statement: Institutional Review Board approval was achieved (IRCCS Burlo Garofolo – 03/2020).