C58-13 Organizing Pneumonia With Environmental Dependence: A Case of Repeated Relapse

Abstract Introduction Cryptogenic organizing pneumonia (COP) is an idiopathic form of organizing pneumonia, characterized histopathologically by intra-alveolar granulation tissue with preserved lung architecture. Clinical presentation is nonspecific, typically with subacute cough, dyspnea, and fever. Radiographically, it manifests as patchy or migratory consolidations often peripheral or peribronchial. Before diagnosing COP, secondary causes, such as infection, connective tissue disease, drug toxicity, or environmental exposure, must be excluded. While most patients respond well to corticosteroids, relapses are frequent during tapering, posing management challenges when environmental triggers cannot be fully avoided. Case A 68-year-old farmer with lifelong exposure to hay, cattle, and sawmill dust presented with a one-month history of progressive dyspnea on exertion, fevers, and body aches. Despite multiple antibiotics and steroid courses, symptoms persisted. Chest CT revealed multifocal consolidative opacities in the upper and lower lobes of the left lung. Bronchoscopy with transbronchial and endobronchial biopsies confirmed organizing pneumonia, with no evidence of malignancy, infection, or autoimmune disorders on additional workup. He was discharged on prednisone 40 mg daily and Bactrim for PJP prophylaxis. His symptoms and imaging significantly improved with prednisone, allowing him to resume farm activities. However, upon tapering below 15 mg/day, his symptoms recurred with new radiographic infiltrates (Fig 1). Mycophenolate mofetil was initiated as a steroid-sparing agent but discontinued after development of a severe, widespread, pruritic rash. He remains on prednisone 20mg daily with atovaquone for PJP prophylaxis as he also developed a rash on bactrim. Given his significant exposure to organic dust and pesticides, environmentally mediated secondary organizing pneumonia remains possible, yet exposure avoidance is limited due to his lifestyle. Discussion This case highlights the diagnostic overlap between COP and environmentally induced organizing pneumonia, particularly in patients with agricultural exposures. The patient’s reproducible steroid responsiveness with relapses at low doses suggests ongoing antigenic stimulation or persistent immune activation. Management must balance the risks of chronic steroid therapy with the feasibility of exposure reduction and the patient’s occupational realities. When steroid toxicity or dependence limits therapy, alternatives such as azathioprine, leflunomide, or macrolides may be considered, though data is limited. The challenge moving forward lies in definitively classifying his organizing pneumonia as cryptogenic versus secondary OP and addressing the potential contribution of agricultural exposures, as meaningful exposure avoidance would require significant lifestyle modification. Ultimately, management should emphasize individualized, context-sensitive strategies that account for occupational feasibility and patient quality of life. This abstract is funded by: None