ABSTRACT
Background The emergence of Multisystem Inflammatory Syndrome in Children (MIS-C) during the SARS-CoV-2 pandemic led to the development of institutional clinical pathways based on expert opinion. We assessed North American pediatric centers’ adaptation to MIS-C and analysed the degree of agreement between algorithms on tiered clinical investigations. Methods This study evaluated MIS-C diagnostic algorithms from 50 tertiary centers developed between May 2020 and December 2021 in the United States and Canada obtained online and through colleagues in various institutions. Descriptive statistics were used to analyse results. Results All clinical pathways used a tiered approach and most required COVID-19 polymerase chain reaction testing on presentation. Over one quarter used a 24-hour fever to initiate investigations and another quarter used 3 days. Basic biochemical work up was performed in all centers on presentation (complete blood count, inflammatory markers, hepatic and renal functions). Specialized investigation was generally reserved for secondary testing (cardiac biomarkers, electrocardiogram and echo, and coagulation panel). Institutions were divided on several investigations for tier distribution, including urine studies, blood cultures, chest radiograph and SARS-CoV-19 serology. Subspecialty consultations were reserved for second-line testing, including cardiology, infectious disease, and rheumatology. Finally, we propose a composite algorithm representative of the consulted pathways. Conclusions Faced with an unprecedented clinical challenge, pediatric institutions responded swiftly with evaluation standardization, adapting to evolving knowledge. Most pathways agreed on initial basic screening tests followed by secondary workup including cardiac investigations. These protocols, developed during a high level of uncertainty, require comparative assessment on efficacy and superiority.