A closer view of the lung shows the focal area of dilated bronchi extending to the pleural surface, typical of localized bronchiectasis. Bronchiectasis tends to be localized with disease processes such as neoplasms and aspirated foreign bodies that block a portion of the airways.

Widespread bronchiectasis is typical for patients with cystic fibrosis who have recurrent infections and obstruction of airways by mucus throughout the lungs. About 2/3 of CF cases are due to the delta F508 mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, but there are hundreds of mutations documented. Different mutations can account for varying degrees of severity of this disease. The major problem is recurrent pulmonary infection, so keeping airways clear of viscid mucus and treating infections with antibiotics improves the quality of life and promotes longevity. The drug lumacaftor enables the abnormal CFTR protein to be transported to the cell surface, and the drug ivacaflor promotes chloride ion transport by the mutated CFTR protein.