ABSTRACT
BACKGROUND: Patients with Multisystem Inflammatory Syndrome in Children (MIS-C) and Kawasaki disease (KD) have overlapping clinical features. We compared demographics/clinical presentation, management, and outcomes of patients by evidence of prior SARS-CoV-2 infection. METHODS: The International KD Registry (IKDR) enrolled KD and MIS-C patients from sites from North, Central and South America, Europe, Asia and Middle East. Evidence of prior infection was defined as: Positive (+ve household contact or positive PCR/serology), Possible (suggestive clinical features of MIS-C and/or KD with negative PCR or serology but not both), Negative (negative PCR and serology and no known exposure), and Unknown (incomplete testing and no known exposure). RESULTS: Of 2345 enrolled patients SARS-CoV-2 status was Positive for 1541 (66%) patients, Possible 89 (4%), Negative 404 (17%) and Unknown for 311 (13%) patients. Clinical outcomes varied significantly between the groups, with more patients in the Positive/Possible groups presenting with shock, having admission to Intensive Care, receiving inotropic support, and having longer hospital stays. Regarding cardiac abnormalities, patients in the Positive/Possible groups had a higher prevalence of left ventricular dysfunction, while patients in the Negative and Unknown groups had more severe coronary artery abnormalities. results CONCLUSION: : There appears to be a spectrum of clinical features from MIS-C to KD with a great deal of heterogeneity, and one primary differentiating factor is evidence for prior acute SARS CoV2 infection/exposure. SARS-CoV-2 Positive/Possible patients had more severe presentations and required more intensive management, with a greater likelihood of ventricular dysfunction but less severe coronary artery adverse outcomes, in keeping with MIS-C.