What condition is characterized by irreversible dilation of the bronchi?

Bronchiectasis is characterized by the irreversible dilation of the bronchi, which is a result of chronic inflammation and infection that damage the airway walls. This condition leads to symptoms such as chronic cough, sputum production, and recurrent respiratory infections due to impaired clearance of mucus and pathogens from the airways. The dilated bronchi can become a site for bacterial colonization, further exacerbating inflammation and leading to a cycle of respiratory complications.

In contrast, chronic bronchitis involves chronic inflammation of the airways but does not result in the irreversible dilation of the bronchi; rather, it is characterized by increased mucus production and airway obstruction. Pneumonia is an infection that affects the lung parenchyma and can cause inflammation of the airways but does not lead to bronchi dilation. Asthma is a reversible obstructive airway disease associated with bronchoconstriction and inflammation but also does not cause permanent changes in the airway structure like bronchiectasis does.