Abstract: SESSION TITLE: Post-COVID-19 Infection Complications SESSION TYPE: Case Report Posters PRESENTED ON: 10/17/2022 12:15 pm - 01:15 pm INTRODUCTION: We present two cases of symptomatic post-COVID eosinophilic pneumonia responsive to steroids. CASE PRESENTATION: Case 1: A 73-year-old gentleman with underlying asymptomatic rheumatoid arthritis (RA), was admitted with COVID pneumonia for which he received tocilizumab, remdesivir, and 12 days of dexamethasone. His course was complicated by MRSA pneumonia and bacteremia, so was discharged on IV Vancomycin. Six days post discharge, he redeveloped respiratory distress. Labs showed a WBC 18,000 and proBNP 2828. A chest CT revealed bilateral ground-glass opacities, worsening right upper lung airspace disease and bilateral pleural effusions. Despite receiving Furosemide, Vancomycin, and Ceftazidime, he required high-flow nasal cannula oxygenation (HFNC). Bronchoscopy demonstrated thick right bronchial secretions. BAL fluid revealed 7% eosinophils and grew MRSA. Case 2: A 70-year-old gentleman with extensive smoking history, emphysema, psoriasis, Guillain-Barré syndrome and a recent hospitalization for COVID pneumonia was discharged on a steroid taper. He returned 23 days post discharge in respiratory distress requiring HFNC, 5 days after discontinuing steroids. The chest CT revealed worsening fibrosis and bronchiectasis. Intravenous Levofloxacin and Vancomycin resulted in no clinical improvement. Bronchoscopy showed inflamed bronchi with secretions and BAL analysis revealed 6% eosinophils. For both patients, BAL was negative for fungi and PJP and CTA ruled out PE. Both patients were started on Prednisone with a prolonged taper. They improved clinically with decreased oxygen requirements to 4L nasal cannula and dramatic decrease in subjective dyspnea within 48 hours of starting steroids. DISCUSSION: The differential diagnosis for the clinical deterioration and worsening radiographs in both patients includes bacterial/fungal superinfection, PE, post-COVID-ILD and eosinophilic pneumonia. For the first patient, his RA was inactive. His BAL was positive for MRSA but did not improve until steroids were initiated. Neither of the patients were stable for VATS biopsy. Eosinophilic pneumonia is defined as pulmonary infiltrates with peripheral blood eosinophilia =500/ml, BAL eosinophils > 5% or eosinophilic infiltration on lung biopsy [1]. Both of our patients had >5% BAL eosinophils. Potentially, prolonged COVID-ILD stimulates T-Helper-2 cells, causing the release of IL-4/5/13 with recruitment of eosinophils. Studies report post-COVID-ILD biopsies show organizing pneumonia and fibrosis but have not yet been associated with eosinophilia. In both patients, we observed eosinophilia on BAL. It can be hypothesized that a delayed inflammatory response mediated by eosinophils play a role. CONCLUSIONS: Pulmonary eosinophilic pneumonia is a complication of post-COVID-ILD and can be successfully managed with steroids. Reference #1: De Giacomi F, Vassallo R, Yi ES, Ryu JH. Acute Eosinophilic Pneumonia. Causes, Diagnosis, and Management. Am J Respir Crit Care Med. 2018 Mar 15;197(6):728-736. doi: 10.1164/rccm.201710-1967CI. PMID: 29206477. DISCLOSURES: No relevant relationships by farrukh ahmad No relevant relationships by Deborah Markowitz No relevant relationships by Dhiraj Shah No relevant relationships by Garima Singh No relevant relationships by Aakriti Soni