Respiratory CAS Practice Exam

The main idea is how emphysema destroys the lung’s acinar units. The acinus, starting at the respiratory bronchiole and including the alveolar ducts and sacs, can be damaged in different patterns. In panacinar emphysema, the destruction is uniform across the entire acinus—every part is involved. This pattern is classically linked to alpha-1 antitrypsin deficiency and often affects the lower lungs. In contrast, centriacinar emphysema targets mainly the proximal part of the acinus around the respiratory bronchioles, with distal alveolar parts relatively spared. That’s typically seen with smoking. Bronchiectasis isn’t an emphysema pattern at all; it’s dilation of the bronchi from chronic infection and wall damage, a different process. Lower lobe emphysema describes location rather than a destruction pattern of the acinus, and while panacinar can be lower-lobe predominant, the defining feature here is the uniform involvement of the whole acinus. So the description that fits all parts of the acinus being damaged is panacinar emphysema.