“From Antigen Exposure to Right Heart Failure: Chronic Hypersensitivity Pneumonitis Due to Bird Fancier’s Lung”: A Case Report

Abstract

Chronic hypersensitivity pneumonitis (CHP) is an immune-mediated interstitial lung disease resulting from prolonged antigen exposure, which can lead to progressive pulmonary fibrosis, pulmonary hypertension (PH), and cor pulmonale. We present a 46-year-old female with a 30-year history of domestic poultry rearing who presented with progressive exertional dyspnea (NYHA class III), bilateral lower limb edema, and abdominal distension. Clinical examination revealed hypoxemia (SpO₂ 84% on room air), elevated jugular venous pressure, bilateral basal crepitations, a parasternal heave, a loud P₂, and signs of right heart failure, including hepatomegaly and ascites. High-resolution computed tomography (HRCT) of the chest demonstrated features consistent with fibrotic interstitial lung disease, including septal thickening, ground-glass opacities, mosaic attenuation, and air trapping, alongside cardiomediastinal findings of right heart and pulmonary artery enlargement. Echocardiography confirmed severe pulmonary arterial hypertension, right atrial and ventricular dilation, paradoxical septal motion, and severe tricuspid regurgitation, establishing the diagnosis of cor pulmonale. Serological workup was negative for connective tissue disease. The final diagnosis was chronic hypersensitivity pneumonitis (bird fancier’s lung) with fibrotic progression, leading to pulmonary arterial hypertension, cor pulmonale, and right-sided heart failure. Management centered on strict antigen avoidance, supplemental oxygen, diuretics, and supportive care, resulting in clinical stabilization. This case underscores the severe cardiopulmonary sequelae of advanced CHP, highlights the critical importance of early occupational and exposure history-taking, and reinforces the foundational role of antigen avoidance in management, even in established fibrotic disease, to mitigate functional decline and mortality.