American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What condition is often associated with increased TLC and RV?

1. Restrictive lung disease

2. Obstructive lung disease

3. Pneumothorax

4. Asthma

The correct answer is: Obstructive lung disease

Increased total lung capacity (TLC) and residual volume (RV) are characteristic of obstructive lung disease, where airflow limitation leads to an inability to fully exhale air from the lungs. Conditions such as chronic obstructive pulmonary disease (COPD) and emphysema are typical examples of obstructive diseases, where air trapping occurs due to narrowed airways, resulting in an increase in RV. Additionally, the lungs may become hyperinflated in these conditions, which contributes to a higher TLC. In contrast, restrictive lung diseases are characterized by reduced lung volumes including TLC and RV, primarily due to lung parenchymal disease or conditions that restrict expansion of the thorax, such as pulmonary fibrosis or pleural effusions. Pneumothorax can lead to lung collapse on the affected side, which may reduce lung volume but is not associated with overall increased TLC or RV. Asthma, while having some obstructive features, typically does not lead to permanent changes in lung volumes as seen in chronic obstructive lung disease.