9-07: Bronchiectasis

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.

A. Symptoms and Signs

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.

B. Imaging

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.

C. Microbiology

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.

Treatment of acute exacerbations consists of antibiotics, daily chest physiotherapy with postural drainage and chest percussion, and inhaled bronchodilators. Handheld flutter valve devices may be as effective as chest physiotherapy in clearing secretions. Antibiotic therapy should be guided by sputum smears and prior cultures. If a specific bacterial pathogen cannot be isolated, then empiric oral antibiotic therapy for 10–14 days is appropriate. Common regimens include amoxicillin or amoxicillin-clavulanate (500 mg every 8 hours), ampicillin (250–500 mg four times daily), doxycycline (100 mg twice daily), trimethoprim-sulfamethoxazole (160/800 mg every 12 hours), or ciprofloxacin (500–750 mg twice daily). It is important to screen patients for infection with nontuberculous mycobacteria because these organisms may underlie a lack of treatment response. Preventive or suppressive treatment is sometimes given to stable outpatients with bronchiectasis who have copious purulent sputum. Prolonged macrolide therapy (azithromycin 500 mg three times a week for 6 months or 250 mg daily for 12 months) has been found to decrease the frequency of exacerbations compared to placebo. Alternating cycles of the antibiotics listed above given orally for 2–4 weeks are also used in patients who are not colonized with Pseudomonas, although this practice is not supported by clinical trial data. In patients with underlying cystic fibrosis, inhaled aerosolized aminoglycosides reduce colonization by Pseudomonas species, improve FEV₁, and reduce hospitalizations; in patients with non–cystic fibrosis bronchiectasis, the role of inhaled aerosolized aminoglycosides is unclear. Complications of bronchiectasis include hemoptysis, cor pulmonale, amyloidosis, and secondary visceral abscesses at distant sites (eg, brain). Bronchoscopy is sometimes necessary to evaluate hemoptysis, remove retained secretions, and rule out obstructing airway lesions. Massive hemoptysis may require embolization of bronchial arteries or surgical resection. Surgical resection is otherwise reserved for the few patients with localized bronchiectasis and adequate pulmonary function in whom conservative management fails.