Which respiratory condition is characterized by alveolar destruction?

Emphysema is a respiratory condition characterized by the destruction of alveoli, the tiny air sacs in the lungs where gas exchange occurs. In emphysema, the walls between the alveoli become damaged, leading to a reduction in the surface area available for oxygen and carbon dioxide exchange. This destruction results in fewer, larger air sacs instead of many small ones, which compromises the efficiency of breathing and can lead to symptoms such as shortness of breath and a chronic cough.

Understanding emphysema as primarily an issue involving the alveoli is key to recognizing its distinction from other respiratory conditions. For instance, bronchitis primarily involves inflammation and narrowing of the bronchial tubes rather than destruction of alveolar tissue. Asthma is characterized by episodic airway constriction and inflammation, and pneumonia involves inflammation of the alveoli often due to infection, which does not correlate with the structural damage seen in emphysema. Thus, emphysema is the correct answer because its defining characteristic is the actual destruction of alveolar structures.