Which statement about contraction atelectasis is true?

• A. It results from acute infection causing airway obstruction.
• B. It is fully reversible with bronchodilators.
• C. It is caused by airway resorption of trapped air.
• D. It is due to fibrotic changes and is NOT reversible.

Answer: (D)

Contraction atelectasis arises from fibrotic changes in the lung or pleura that pull the lung tissue inward, producing a fixed loss of lung volume. Because the underlying scarring and tissue retraction are permanent, the affected areas cannot re-expand, even if airways are opened or obstruction is relieved. Bronchodilators don’t reverse fibrosis or the mechanical retraction, so they won’t restore the collapsed lung. By contrast, atelectasis from airway obstruction or external compression is driven by trapped air or external pressure and may be reversible when the obstruction or pressure is removed. The hallmark of contraction atelectasis is the irreversible fibrotic retraction leading to persistent volume loss.