Multisystem Inflammatory Syndrome in Children (MIS-C) in an Adolescent that Developed Coronary Aneurysms: A Case Report and Review of the Literature.

Background: A small subset of pediatric patients develop a rare syndrome associated with Coronavirus Disease 2019 (COVID-19) infection called multisystem inflammatory syndrome in children (MIS-C). This syndrome shares characteristics with Kawasaki disease.

Case Report: A 15-year-old girl presented to our Emergency Department (ED) with fevers and malaise. She was diagnosed on her initial visit with an acute viral syndrome and discharged with a COVID polymerase chain reaction test pending, which was subsequently negative. She returned 3 days later with persistent fever, conjunctivitis, and a symmetric targetoid rash over her palms. She had no adenopathy, but her erythrocyte sedimentation rate and C-reactive protein were both significantly elevated at 90 mm/h and 19.61 mg/dL, respectively. The patient was then transferred to the regional children's hospital due to a clinical suspicion for MIS-C, and subsequent COVID-19 immunoglobulin G testing was positive. She had been empirically started on intravenous immunoglobulin in addition to 81 mg aspirin daily. Initial echocardiograms showed mild dilatation of the left main coronary artery, and on repeat echocardiogram, a right coronary artery aneurysm was also identified. Oral prednisone therapy (5 mg) was initiated and the patient was discharged on a continued prednisone taper. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: We present a case of a 15-year-old girl who presented to the ED with MIS-C who developed coronary aneurysms despite early therapy, to increase awareness among emergency physicians of this emerging condition.