Discriminating MIS-C Requiring Treatment from Common Febrile Conditions in Outpatient Settings.

OBJECTIVES To examine whether patients with multisystem inflammatory syndrome in children (MIS-C) demonstrated well-defined clinical features distinct from other febrile outpatients given the difficulties of seeing acute care visits during the SARS-CoV-2 pandemic and the risks associated with both over and underdiagnosis of MIS-C. STUDY DESIGN This case-controlled study compared patients diagnosed with and treated for MIS-C at a large urban children's hospital with patients evaluated for fever at outpatient acute care visits during the peak period of MIS-C. Symptomatology and available objective data were extracted. Comparisons were performed using t-tests with corrections for multiple comparisons, and multivariable logistic regression to obtain odds ratios. RESULTS We identified 44 patients with MIS-C between April 16 and June 10, 2020. During the same period 181 pediatric patients were evaluated for febrile illnesses in participating outpatient clinics. MIS-C patients reported higher median Tmax (40 degrees C vs 38.9, P < .0001), and increased frequency of abdominal pain (OR 12.5, 95% CI [1.65-33.24]), neck pain (536.5, [2.23-129,029]), conjunctivitis (31.3, [4.6-212.8]), oral mucosal irritation (11.8, [1.4-99.4]), extremity swelling or rash (99.9, [5-1960]) and generalized rash (7.42, [1.6-33.2]). Patients with MIS-C demonstrated lower absolute lymphocyte (p<0.0001) and platelet counts (p<0.05) and higher C-reactive protein concentrations (p<0.001). CONCLUSIONS Patients treated for MIS-C due to concern for potential cardiac injury show combinations of features distinct from other febrile patients seen in outpatient clinics during the same period.