PC1021: Identification of Febrile Children at Low Risk for MIS-C in the Emergency Department

Background: The multisystem inflammatory syndrome in children (MIS-C) case definition is broad and encompasses symptoms and signs commonly seen in children with fever. Our aim was to derive a model for children with fever and concern for MIS-C that identified children at low risk of MIS-C using clinical variables alone.

Methods: We conducted a retrospective review of children 2 months to 20 years presenting to the emergency department (ED) for evaluation of fever and concern for MIS-C during the first wave of MIS-C in New York City. Concern for MIS-C was based on having obtained a MIS-C-specific laboratory evaluation in our ED, which was broadly used to evaluate children with fever during this period. We defined MIS-C based on the CDC criteria. All patients with MIS-C were reviewed by an interdisciplinary team to obtain consensus on diagnosis. The comparison group was children with non-MIS-C and non-Kawasaki disease diagnoses. We abstracted a comprehensive list of clinical findings on index ED visit using a standardized manual of operations. We determined interobserver agreement for abstraction on 10%. We conducted multivariable logistic regression (LR) analyses to identify variables independently associated with the MIS-C, and used independent variables from LR and recursive partition analyses to identity children at low risk of MIS-C.

Results: Thirty-three patients with and 125 patients without MIS-C were analyzed. In the ED, 16/33 (48.5%) with MIS-C were hypotensive, had signs of hypoperfusion, or required ionotropic support. Table notes the clinical findings differing between groups. Of the 125 patients without MIS-C, 27 (21.6%) were hospitalized. Two children evaluated for fever were discharged from the ED on index visit and were subsequently admitted on return visit with MIS-C diagnoses. Four variables were independently associated with the presence of MIS-C; SARS CoV-2 exposure (adjusted OR 4.0 95% CI 1.4, 12.1) and three symptoms and signs, abdominal pain on history (adjusted OR 5.0 95% CI 1.8, 15.7), conjunctival injection (adjusted OR 14.5 95% CI 5.1, 46.0), and rash involving palms or soles (adjusted OR 11.9 95% CI 2.4, 67.8). The absence of all three symptoms and signs had a sensitivity 87.9% (95% CI 71.8-96.6), specificity 63.2% (54.1-71.7), and negative predictive value 95.2% (88.6-98.0) to identify MIS-C. Of the 4 MIS-C patients without these 3 factors, 2 were ill-appearing in the ED and the 2 other had no cardiovascular involvement during their clinical course. Of those who were well appearing, neither had evidence of two organ system involvement on history or physical exam alone.

Conclusion: Children without the specific symptoms and signs are at low risk of MIS-C. If validated, these factors could aid clinicians in determining the need to obtain or forego an MIS-C laboratory evaluation during SARS-CoV-2 prevalent periods in children with fever who are not severely ill.