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How can cystic fibrosis lead to bronchiectasis?

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Medical illustration of the human chest showing the lungs, diaphragm, ribs, trachea, bronchus, and bronchioles, with one lung cut away to reveal internal structures. — respiratory disease The bronchioles of the lungs are the site where oxygen is exchanged for carbon dioxide during the process of respiration. Inflammation, infection, or obstruction of the bronchioles is often associated with acute or chronic respiratory disease, including bronchiectasis, pneumonia, and lung abscesses.

Cystic fibrosis leads to bronchiectasis primarily by predisposing the lungs to chronic, recurrent infections and airway obstruction.1

In individuals with cystic fibrosis, a genetic mutation causes the production of thick, sticky mucus that accumulates in the lungs and plugs the bronchi. This obstruction leads to the stagnation of secretions, which creates an environment conducive to persistent bacterial infections.21

These chronic infections cause ongoing inflammation of the bronchial walls. Over time, this inflammatory process leads to the degeneration of the elastic and muscle fibers within the airway walls. This structural weakening allows the bronchial tubes to dilate abnormally, a condition defined as bronchiectasis. Once this dilatation occurs, it creates a cycle where further secretions accumulate and infections spread and intensify, causing progressive damage to the lung tissue.1