What condition is characterized by chronic dilation and distortion of one or more bronchi?

Bronchiectasis is characterized by chronic dilation and distortion of one or more bronchi, resulting from a cycle of infection and inflammation that leads to damage of the bronchial walls. This condition can be caused by various factors, including chronic infections, autoimmune diseases, or genetic disorders such as cystic fibrosis.

In bronchiectasis, the airways become enlarged and lose their ability to clear mucus effectively, which can lead to recurrent respiratory infections and difficulty breathing. The damaged bronchi can also create a favorable environment for bacterial growth, further exacerbating the problem.

In contrast, asthma involves reversible airway obstruction due to inflammation and bronchoconstriction, while chronic bronchitis is primarily associated with a productive cough and inflammation of the bronchial tubes without the permanent dilation seen in bronchiectasis. Pneumonia is an acute condition characterized by inflammation of the lung parenchyma due to infection and does not involve chronic airway dilation. Thus, the defining characteristic of bronchiectasis distinguishes it as the correct answer.