Multisystem inflammatory syndrome in children (MIS-C) temporally associated with SARS-CoV-2 infection: a scoping review of the literature

Background: With the rise of the COVID-19 pandemic, a new severe life-threatening inflammatory syndrome has been reported in some pediatric populations. Global attention was shifted towards the syndrome termed multisystem inflammatory syndrome in children (MIS-C), with new case reports flooding in. Objectives: The aim of this scoping review is to summarize the existing reports on MIS-C and focus on the demographics, diagnosis, clinical presentation, laboratory investigations, imaging studies, treatment, and patient outcomes. Methods: We conducted a systemic search using LitCovid and MEDLINE electronic databases. We screened citations, titles and abstracts, then reviewed potentially relevant articles in full. After data extraction, we reported our final data under subheadings of demographics, diagnosis, clinical presentation, laboratory investigations, imaging studies, treatment, and patient outcomes. Results: Our search strategy yielded 42 original studies reporting 674 pediatric patients fitting the case definition of MIS-C. The studies included 21 case reports, 16 case series and 5 cohort studies. The most common reported symptom of MIS-C was fever (98%). Gastrointestinal symptoms were common (N=557, 83%). Interleukin-6 (IL-6) levels were measured in 125 patients and was elevated in 94 % (N=117). Echocardiography detected coronary artery lesions in 100 patients. Prophylactic and/or therapeutic heparin was required in 34% (N=227) of patients. The most commonly administered treatment modality targeting MIS-C was intravenous immunoglobulin (IVIG) (N=490). Corticosteroids (N=347) and aspirin (N=112) were also integral parts of the treatment regimens. Biologic therapy was integrated into the treatment regimen for 116 patients. Intensive care unit (ICU) admission was alarming (N=478, 71%). 9 fatalities were recorded due to MIS-C Conclusions: We believe MIS-C bears pathophysiological resemblance to the well-known Kawasaki disease but with some key differences highlighted. Understanding those differences will aid our management plan for such patients.