A35-15 Case of Eosinophilic Granulomatosis With Polyangiitis Treated With Mepolizumab

Abstract Introduction Eosinophilic granulomatosis with polyangiitis (EGPA) is a multisystem disorder caused by medium-vessel vasculitis. It classically initially presents as adult-onset severe asthma, sinusitis, and peripheral eosinophilia. Diagnosing EGPA can be challenging due to lack of diagnostic criteria and systemic symptoms often occur later in the disease process. Case report A 57-year-old female with a history of asthma and hypothyroidism presents to the pulmonary outpatient clinic after several recent ED visits for asthma exacerbations. She endorsed asthma since childhood, which was always well controlled with as-needed albuterol inhalers. However, this has recently progressed over the past five years to completely uncontrolled and debilitating asthma symptoms with 23 presentations to the Emergency Department and one admission during this period. On further evaluation, CT chest shows no interstitial lung disease or emphysema but is significant for diffuse bilateral ground glass opacities and thickened medium and small airways. Three months later, she develops a cough and a rash and is started on daily prednisone. She is unable to taper off prednisone without her cough returning. She underwent bronchoscopy which showed interstitial expansion with increased eosinophils around small vessels and focal intra-alveolar eosinophils, and eosinophilia on bronchoalveolar lavage. With clinical history, BAL findings, history of serum eosinophils 1200, and recent rash eruption, she was started on mepolizumab for EGPA with significant improvement. Since starting therapy, she has only had one respiratory-related emergency room presentation and one steroid course for a total of five days in the last five years, an improvement from 10.9g of prednisone in 18 months prior to initiation. Discussion EGPA is often difficult to diagnose with systemic symptoms presenting in the third stage of the disease course, or not at all, especially in ANCA-negative cases such as this one. Though corticosteroids and immunosuppressants remain the mainstay of treatment for EGPA, this case highlights a profound and rapid response to mepolizumab. Treatment with anti-IL-5 monoclonal antibodies in this patient effectively eliminated exacerbations, limiting daily steroid use and unburdening the healthcare system. Additionally, though typically low yield, this case highlights the possibility of confirming tissue diagnosis of EGPA with traditional transbronchial biopsy. This abstract is funded by: None