In which condition is lung compliance increased?

• A. Emphysema
• B. Pleural effusion
• C. Pulmonary fibrosis
• D. Pulmonary edema

Answer: (A)

In the case of emphysema, lung compliance is increased due to the destruction of alveolar walls and loss of elastic recoil that occurs in the lungs. This condition typically leads to a more distensible lung, allowing it to expand more easily when air is drawn in. The structural changes in the lung tissue result in decreased elasticity, which reduces the lungs' ability to return to their original shape after inhalation, thereby increasing compliance.

This is in contrast to conditions like pulmonary fibrosis, pleural effusion, and pulmonary edema, where lung compliance is usually decreased due to stiffening of lung tissue, fluid accumulation, or pressure changes that limit lung expansion. Each of these conditions impedes normal ventilation, hence reducing compliance, while emphysema indicates a different pathological mechanism that results in increased compliance.