Role of Conventional Radiography and High-Resolution Computed Tomography for Post Infectious Bronchiolitis Obliterans (PIBO): A Case Report

Introduction: Post-infectious bronchiolitis obliterans (PIBO) is a rare and severe lung disease characterized by chronic inflammation and irreversible changes in the small airways following lower respiratory tract infections or other insults. Case Description: A two-year-old boy presented with a cough and shortness of breath that had worsened over the past month. The child had experienced recurrent respiratory symptoms for four months and had a history of bronchopneumonia the previous year. Despite treatment with corticosteroids, his symptoms persisted, leading to further investigation. Chest x-ray (CXR) showed peribronchial thickening, hyperinflation, and reduced vascular markings in both lung fields. High-resolution computed tomography (HRCT) revealed bilateral mosaic attenuation with areas of decreased lung attenuation and patchy ground-glass opacities involving multiple lung segments, accompanied by focal fibrotic changes. As in this case, chest x-ray findings in PIBO are often inconclusive, and HRCT is essential for diagnosis. The mosaic attenuation pattern on HRCT is a hallmark of PIBO, caused by ventilation-perfusion mismatch due to localized airway obstruction and vascular shunting. Conclusion: Chest x-ray may show non-specific findings in PIBO, whereas HRCT provides characteristic imaging features that are crucial for diagnosis. HRCT plays a pivotal role in confirming PIBO by demonstrating mosaic attenuation and associated airway abnormalities, thereby facilitating accurate diagnosis and appropriate clinical management.