Which factor causes upper-lobe emphysema?

Which factor causes upper-lobe emphysema?

• A. Smoking
• B. Alpha-1 Antitrypsin Deficiency
• C. Bronchiectasis
• D. Polycythemia

Answer: (A)

Smoking drives upper-lobe emphysema by producing centrilobular destruction of the respiratory bronchioles in the lung apices. The inhaled smoke triggers inflammation with neutrophils and macrophages releasing elastase and other proteases, while smoke also impairs antiprotease defenses. This protease‑antiprotease imbalance plus oxidative stress preferentially damages the central portions of the acinus in the upper lobes, leading to early emphysema there. In contrast, alpha-1 antitrypsin deficiency tends to cause a panacinar pattern that often involves the lower lobes, bronchiectasis is a different airway disease, and polycythemia is not a cause of emphysema.

Smoking drives upper-lobe emphysema by producing centrilobular destruction of the respiratory bronchioles in the lung apices. The inhaled smoke triggers inflammation with neutrophils and macrophages releasing elastase and other proteases, while smoke also impairs antiprotease defenses. This protease‑antiprotease imbalance plus oxidative stress preferentially damages the central portions of the acinus in the upper lobes, leading to early emphysema there. In contrast, alpha-1 antitrypsin deficiency tends to cause a panacinar pattern that often involves the lower lobes, bronchiectasis is a different airway disease, and polycythemia is not a cause of emphysema.