Advanced Imaging and Occupational History in the Diagnosis of Bird Fancier's Lung: A Case Report.

Bird fancier's lung (BFL) is a subtype of hypersensitivity pneumonitis (HP), an immune-mediated interstitial lung disease (ILD) resulting from the repeated inhalation of avian proteins found in bird droppings, feathers, and serum. Diagnosing BFL is challenging due to nonspecific symptoms that overlap with other ILDs like idiopathic pulmonary fibrosis and sarcoidosis. This complexity is heightened during pandemics such as coronavirus disease 2019 (COVID-19), where respiratory symptoms may be misattributed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, leading to diagnostic anchoring and delays in appropriate management. High-resolution computed tomography (HRCT) is pivotal in detecting subtle pulmonary changes, characteristic of HP, surpassing standard chest radiographs. We present the case of a 43-year-old male pigeon keeper with an eight-week history of progressive dyspnea on exertion and intermittent chest pain. Despite unremarkable chest X-rays, HRCT revealed bilateral diffuse centrilobular nodules, patchy ground-glass opacities, and a mosaic attenuation pattern without fibrosis, consistent with acute HP. A thorough occupational history uncovered significant avian antigen exposure, and a family history suggested genetic susceptibility. The patient was diagnosed with BFL and treated with a tapering regimen of oral corticosteroids, starting at 40 mg/day. He was advised to cease pigeon keeping and avoid future avian exposure. Significant symptomatic improvement occurred within three months. Follow-up imaging over one year confirmed stable lung parenchyma with no disease progression or recurrence. This case underscores the importance of incorporating detailed occupational histories and utilizing advanced imaging modalities like HRCT when standard imaging is inconclusive. Early identification and intervention are crucial to prevent progression to chronic HP and irreversible fibrosis. Management should focus on reducing inflammation with corticosteroids and implementing strict environmental controls to prevent re-exposure. Long-term follow-up is essential to monitor for recurrence and maintain remission. Clinicians should remain vigilant for alternative diagnoses during pandemics to avoid diagnostic anchoring. This case contributes to the evidence supporting HRCT's critical role in early HP detection and emphasizes heightened clinical awareness of occupational lung diseases. A multidisciplinary approach involving pulmonologists, radiologists, and occupational medicine specialists is key to optimizing outcomes in HP and other ILDs.