Background Multisystem inflammatory syndrome in children (MIS-C) or Paediatric inflammatory multisystem syndrome is a newly emerged hyper-inflammatory syndrome that is associated with SARS-CoV-2 infection in the paediatric population.

Objectives We aim to identify commonly presented clinical features, imaging findings, laboratory findings, treatment modalities and clinical outcomes of MIS-C/PIMS. We also aim to compare Kawasaki Disease and MIS-C/PIMS for better identification and management of these patients.

Methods A systematic review was conducted from 1st December 2019 to 30th August 2020. Three medical databases (PubMed, Ovid Resources and the WHO COVID-19 database) were included in this study. Inclusion criteria were all observational studies, case reports or case series that reported data on MIS-C or PIMS.

Results We yielded 48 studies (N=1604) from 12 countries. Median age ranged from 2 to 19.9 years. 88% had positive SARS-CoV-2 PCR or serology tests. Reported clinical features include fever (100%), gastrointestinal symptoms (87%), rash (56%), conjunctivitis (48%) and shock (47%). ECHO abnormalities (N=471) were most commonly reported. Laboratory findings include elevated inflammatory markers (66%-95%), deranged LFTs (54%) and cardiac biomarkers (49%-55%). Common treatment choices: intravenous immunoglobulin (76%), steroids (59%) and aspirin (33%). ICU admission rate was 72% and mortality rate was 2%.

Conclusions MIS-C/PIMS is an immune-mediated complication associated with COVID-19. Clinical manifestation vary and majority presents with evidence of multiorgan dysfunction. Close monitoring and high level of care should be given to suspected or confirmed cases. Supportive care remains the mainstay treatment. While manifestation of MIS-C/PIMS overlaps with KD, it is a distinct entity based on their differences in age distribution, geographical and racial variation, laboratory findings, associated features and clinical outcomes.