Multiple MIS-C Readmissions and Giant Coronary Aneurysm after COVID-19 Illness and Vaccination

Abstract

Introduction Multisystem inflammatory syndrome in children rarely involves severe coronary dilation, multiple readmissions, or occurrence after COVID-19 vaccination. We describe the case of a boy aged 5 years with all three of these unusual features. Case Presentation A previously healthy 5-year-old male was hospitalized with fever for 4 days, sore throat, myalgias, abdominal pain, conjunctivitis, and rash. Symptom onset was 56 days after acute COVID-19 illness and 16 days after receiving one dose of the Pfizer COVID-19 vaccine. Workup was notable for elevated inflammatory markers, mildly elevated cardiac biomarkers with evidence of SARS-CoV-2 infection, including both SARS-COV2-PCR and anti-nucleocapsid antibody. Patient was diagnosed with MIS-C with Kawasaki features, and demonstrated clinical improvement after treatment with IVIG, steroids and aspirin. Echocardiography during the initial hospitalization was reassuring. On day 7 of MIS-C illness, the patient was discharged with low dose aspirin and prednisone. A day after completing his course of prednisone, on day 10 of MIS-C illness, patient presented to the emergency room again with fever, fatigue, rash, conjunctivitis, and dry, cracked lips. Labs were notable for thrombocytosis, leukocytosis, and elevated CRP, ESR, and d-dimer. He was diagnosed with recrudescence of MIS-C with features of Kawasaki disease. He was started on IV methylprednisolone 1 mg/kg, and low dose aspirin. Echocardiography on day 11 was significant for newly dilated coronary arteries with no aneurysms, and patient was promptly started on his second course of IVIG, from which he remained afebrile. Repeat echocardiogram was not notable for any changes. On day 14, patient was discharged with a prednisolone taper and low dose aspirin. Until day 20 of illness, he took 1 mg/kg of prednisolone twice daily. On day 21, patient’s prednisolone was tapered to 1 mg/kg once daily, and he presented with fevers, dry cracked lips, conjunctivitis and abdominal pain on day 23. Inflammatory markers had elevated since previous discharge. Echocardiography was significant for severe dilation to his coronary arteries, especially his right coronary artery (RCA) (4.5 mm) and left anterior descending artery (LAD) (6.7 mm). He began treatment for refractory MIS-C and was started on infliximab and methylprednisolone. He was also given enoxaparin for his coronary artery dilation. On day 25, echocardiography continued to show severe coronary artery dilation, most significant with the LAD. His inflammatory markers and clinical course improved, and on day 28, repeat echocardiography showed no significant change. Patient was discharged on enoxaparin, daily aspirin, and a 30-day steroid taper. He remains asymptomatic, and most recent echocardiogram remains stable with slight improvement. A month after his most recent discharge, his inflammatory markers were found to be increasing, and his steroid taper was adjusted accordingly. Discussion: Our patient was admitted three times for MIS-C refractory to initial treatment with intravenous immunoglobulin, corticosteroids and anti-inflammatory agents. Readmission for MIS-C is not common. Among the 457 cases of MIS-C at our institution, this is the only patient to require 2 readmissions for MIS-C. He also developed giant coronary aneurysms. A diagnosis of MIS-C after COVID-19 vaccination is rare. In a study of vaccination in the United States, only one case occurs per million vaccinated children between the ages of 12-20 were noted to have MIS-C after vaccination. Whether or not the patient should receive his second Pfizer vaccine was questioned. Given current CDC guidelines, no future COVID-19 vaccinations are planned until the patient has at least made a complete recovery from his cardiac complications.