Pathologically, dilation of air spaces distal to the terminal bronchiole with destruction of the interalveolar septa describes which condition?

• A. Chronic bronchitis
• B. Bronchiectasis
• C. Pneumonia
• D. Emphysema

Answer: (D)

Pathologic emphysema is characterized by enlargement of air spaces distal to the terminal bronchioles with destruction of the interalveolar septa. This means the walls between alveoli are broken down, causing fewer but larger air sacs, loss of elastic recoil, and decreased surface area for gas exchange. The result is air trapping and impaired breathing, which fits the description of dilation of distal air spaces with septal destruction.

Other conditions have different tissue changes: chronic bronchitis involves thickened airways with mucous gland enlargement and excess mucus production; bronchiectasis shows permanent dilation and distortion of the bronchi due to airway wall destruction; pneumonia is an infection that fills alveolar spaces with inflammatory exudate rather than destroying alveolar walls.