On chest radiographs, which pattern is most typical of bronchiolitis?

• A. Hyperinflation with peribronchial thickening
• B. Consolidation in a single lobe
• C. Atelectasis
• D. Pleural effusion

Answer: (A)

Bronchiolitis mainly affects the small airways, so the chest radiograph classically shows air trapping with hyperinflation. This happens because inflammation and edema narrow the small bronchioles, making it harder for air to escape during expiration, leading to increased lung volumes. Around the airways, you also see peribronchial thickening from the inflammatory changes in the bronchial walls. The combination of dilated lungs on a pediatric film with visible thickened bronchial markings is the typical pattern clinicians look for in bronchiolitis.

Other radiographic scenarios point to different problems: a focal consolidation would suggest a bacterial pneumonia in a single region, atelectasis would look like localized loss of volume rather than overall enlarged lungs, and a pleural effusion is uncommon in uncomplicated bronchiolitis.