ESSENTIALS OF DIAGNOSIS
Chronic productive cough with dyspnea and wheezing.
Radiographic findings of dilated, thickened airways and scattered, irregular opacities.
Bronchiectasis is a congenital or acquired disorder of the large bronchi characterized by permanent, abnormal dilation and destruction of bronchial walls. It may be caused by recurrent inflammation or infection of the airways and may be localized or diffuse. Cystic fibrosis causes about half of all cases of bronchiectasis. Other causes include lung infection (tuberculosis, fungal infections, lung abscess, pneumonia), abnormal lung defense mechanisms (humoral immunodeficiency, alpha-1-antiprotease [alpha-1-antitrypsin] deficiency with cigarette smoking, mucociliary clearance disorders, rheumatic diseases), and localized airway obstruction (foreign body, tumor, mucoid impaction). Immunodeficiency states that may lead to bronchiectasis include congenital or acquired panhypogammaglobulinemia; common variable immunodeficiency; selective IgA, IgM, and IgG subclass deficiencies; and acquired immunodeficiency from cytotoxic therapy, AIDS, lymphoma, plasma cell myeloma, and leukemia. Most patients with bronchiectasis have panhypergammaglobulinemia, however, presumably reflecting an immune system response to chronic airway infection. Acquired primary bronchiectasis is now uncommon in the United States because of improved control of bronchopulmonary infections.
Symptoms of bronchiectasis include chronic cough with production of copious amounts of purulent sputum, hemoptysis, and pleuritic chest pain. Dyspnea and wheezing occur in 75% of patients. Weight loss, anemia, and other systemic manifestations are common. Physical findings are nonspecific, but persistent crackles at the lung bases are common. Clubbing is infrequent in mild cases but is common in severe disease (Figure 6–42). Copious, foul-smelling, purulent sputum is characteristic. Obstructive pulmonary dysfunction with hypoxemia is seen in moderate or severe disease.
Radiographic abnormalities include dilated and thickened bronchi that may appear as “tram tracks” or as ring-like markings (eFigure 9–6) (eFigure 9–7). Scattered irregular opacities, atelectasis, and focal consolidation may be present. High-resolution CT is the diagnostic study of choice.
Bronchiectasis. Diffuse cystic bronchiectasis resulting in lobar atelectasis of the right lower lobe in an elderly woman. Despite workup, the cause of this bronchiectasis remained unclear.
Bronchiectasis in cystic fibrosis. Chest radiograph of a patient with advanced cystic fibrosis demonstrating fibrotic changes with volume loss of the right lung as well as prominent bronchiectasis with a classic “tram track” appearance in the left upper lobe (arrows).
H influenzae is the most common organism recovered from non–cystic fibrosis patients with bronchiectasis. P aeruginosa, S pneumoniae, and Staphylococcus aureus are commonly identified. Nontuberculous mycobacteria are seen less commonly. Patients with Pseudomonas infection experience an accelerated course, with more frequent exacerbations and more rapid decline in lung function.