Increased total lung capacity is most consistent with which condition?

Increased total lung capacity is most consistent with which condition?

• A. Emphysema
• B. Chronic bronchitis
• C. Restrictive pulmonary disease
• D. Pulmonary emphysema and chronic bronchitis

Answer: (D)

Total lung capacity reflects the maximum amount of air the lungs can hold. In obstructive lung diseases, air is often trapped during exhalation, leading to overinflation or hyperinflation. Emphysema destroys alveolar walls and reduces elastic recoil, so expiration becomes difficult and air remains in the lungs longer, increasing TLC. Chronic bronchitis adds airway narrowing and mucus plugging, also promoting air trapping. Because both conditions can cause air trapping and increased lung volume, the combination of emphysema and chronic bronchitis best fits a rise in TLC. In contrast, restrictive diseases reduce lung volumes and lower TLC, so they do not produce this pattern.

Total lung capacity reflects the maximum amount of air the lungs can hold. In obstructive lung diseases, air is often trapped during exhalation, leading to overinflation or hyperinflation. Emphysema destroys alveolar walls and reduces elastic recoil, so expiration becomes difficult and air remains in the lungs longer, increasing TLC. Chronic bronchitis adds airway narrowing and mucus plugging, also promoting air trapping. Because both conditions can cause air trapping and increased lung volume, the combination of emphysema and chronic bronchitis best fits a rise in TLC. In contrast, restrictive diseases reduce lung volumes and lower TLC, so they do not produce this pattern.