Distinguishing Features of Patients Evaluated for Multisystem Inflammatory Syndrome in Children

Given the significant overlap of multisystem inflammatory syndrome in children (MIS-C) with other common childhood illnesses presenting to the emergency department, extensive workup of this syndrome has become necessary. Nevertheless, little has been published on the factors differentiating MIS-C from other conditions in the acute care setting. We investigated differences in presentation and laboratory studies between suspected versus confirmed MIS-C patients.This was a retrospective cohort study on patients 21 years or younger undergoing investigation for possible MIS-C at a single institution between April 21 and July 1, 2020. The primary outcome was diagnosis of MIS-C or an alternative final diagnosis. Clinical features and laboratory findings from initial presentation were collected and analyzed.A total of 106 patients (median, 4 years; 55.7% male) were included, of whom 17 (16%) of 106 met the criteria for MIS-C. Multisystem inflammatory syndrome in children patients were significantly more likely to report a coronavirus disease 2019 exposure (odds ratio (OR), 13.17 [3.87-44.9]), have gastrointestinal symptoms (OR, 3.81 [1.02-14.19]), and have a significantly higher odds of having abnormal laboratory values including high-sensitivity troponin T (OR, 13 [4.0-42.2]), N-terminal B-type natriuretic peptide (OR, 8.4 [2.3-30.1]), D-dimer (OR, 13 [1.6-103]), and ferritin (OR, 7.8 [2.2-27.2]). There were also differences between groups in inflammatory markers: C-reactive protein (median, 134.45 mg/L vs 12.6 mg/L; P0.05) and procalcitonin (1.71 ng/mL vs 0.14 ng/mL; P0.001).Higher elevations in key laboratory studies may help to distinguish between MIS-C patients and non-MIS-C patients presenting to the emergency department.