Dilation of large conducting airways due to congenital or acquired conditions is called what?

• A. Emphysema
• B. Pleural effusion
• C. Bronchiectasis
• D. Atelectasis

Answer: (C)

Dilation of the large conducting airways occurs in bronchiectasis. This condition results from chronic inflammation or infection that damages the elastic and muscular tissue of the bronchial walls, making the bronchi permanently wider and less able to clear mucus. It can be present from birth (congenital) or develop after repeated infections or obstruction (acquired), with causes such as cystic fibrosis or primary ciliary dyskinesia on the congenital side and chronic infections or immunodeficiency on the acquired side. Patients often have a chronic productive cough with purulent sputum and recurrent chest infections; imaging typically shows bronchi that are abnormally wide and fail to taper toward the periphery (signet ring/ tram-track patterns on CT). Emphysema involves destruction of alveolar walls rather than dilation of the airways, pleural effusion is fluid in the space around the lung, and atelectasis is collapse of lung tissue, not dilation of the airways.