Definition, Etiology, Pathogenesis Top
Bronchiectasis refers to a permanent abnormal dilation and destruction of bronchial walls, which involve both the major bronchi and bronchioles.
1) Congenital bronchiectasis is associated with impaired mucociliary clearance (cystic fibrosis, Young syndrome [bronchiectases with normal ciliary structure, sinusitis, bronchitis, oligospermia, azoospermia], primary ciliary dyskinesia [50% of cases are due to Kartagener syndrome: bronchiectasis, dextrocardia, sinusitis]), primary immunodeficiency, alpha1-antitrypsin deficiency, other rare congenital diseases.
2) Acquired bronchiectasis develops in the course of severe infections (bacterial or measles), diseases causing pulmonary fibrosis (sarcoidosis, pneumoconioses, rheumatoid arthritis, idiopathic pulmonary fibrosis, ankylosing spondylitis, Sjögren syndrome, ulcerative colitis), inhalation of toxic gases, thermal injury, airway obstruction (irrespective of the cause, eg, neoplasm, foreign body), allergic bronchopulmonary aspergillosis, AIDS, postradiation lung injury, gastroesophageal reflux disease, and microaspiration of gastrointestinal contents.
Clinical Features and Natural History Top
1. Symptoms: Chronic cough with production of large amounts of sputum, usually purulent. In some cases, exertional dyspnea, wheezing, hemoptysis, recurrent lower respiratory tract infections, and low-grade fever may be present.
2. Signs: Fine and coarse rales, sometimes bronchial breath sounds, prolonged expiration, wheezes. Patients with advanced disease may develop cyanosis, clubbing of digits, and cachexia.
3. Natural history: The onset is insidious, with progressive development of productive cough followed by gradually developing respiratory failure.
1. Imaging studies: Chest radiographs may be normal in patients with early disease; in patients with advanced bronchiectasis, diffuse opacifications caused by atelectases, the finger-in-glove sign caused by dilated airways filled with mucous secretions, cystic air spaces (some with fluid levels), and pulmonary densities caused by fibrosis or inflammation may be observed. Bronchial wall thickening may produce a “tram tracks” pattern. High-resolution computed tomography (HRCT) is the gold standard test to confirm the diagnosis of bronchiectasis and is more sensitive and more specific than chest radiographs. Typical features include dilation of the airways and thickening of the bronchial walls, a lack of bronchial tapering, the presence of bronchial structures within <1 cm from the chest wall, and the “signet-ring sign.”
2. Bronchoscopy is indicated in patients with unilateral bronchiectasis, a short history of symptoms, or hemoptysis.
3. Other studies to diagnose underlying conditions, including cystic fibrosis, immunodeficiency, abnormal mucociliary clearance, allergic bronchopulmonary aspergillosis.
4. Sputum microbiology is recommended for microscopy, culture, and sensitivity for bacteria, fungi, viruses, and mycobacteria. The most commonly encountered pathogens in bronchiectasis are Haemophilus influenzae and Pseudomonas aeruginosa, followed by Streptococcus pneumoniae, Staphylococcus aureus, nontuberculous mycobacteria, and enterococci.
5. Spirometry is recommended in all patients, at least yearly. Usually obstructive ventilation impairment is observed, the severity of which often correlates with the stage of the disease; in one-third to two-thirds of patients, bronchial hyperresponsiveness is observed.
6. Diagnostic workup of patients hospitalized for exacerbation: Sputum microbiology (optimally the sputum sample should be collected before the start of antimicrobial treatment), chest radiographs, pulse oximetry (or blood gases when indicated), blood cultures (in the case of fever), monitoring of the daily amounts of produced sputum.
Diagnosis is confirmed by HRCT.
Other diseases associated with cough and sputum production (see Cough).
1. Chest physiotherapy and other approaches to facilitate the removal of bronchial secretions: postural drainage combined with vibration and chest percussion; nebulized hypertonic saline, oscillatory positive expiratory pressure devices, and controlled breathing exercises (such as pursed-lip breathing).
2. Antimicrobial treatment: In patients with acute infection, start from empiric therapy with antibiotics active against H influenzae and S aureus: amoxicillin/clavulanic acid. In patients with hypersensitivity to penicillins, administer macrolides (clarithromycin or azithromycin). In patients with severe bronchiectasis and chronic H influenzae colonization, use higher doses of antibiotics (eg, amoxicillin 1 g tid). In patients with P aeruginosa colonization, administer ciprofloxacin and, after the antimicrobial resistance pattern of the sputum cultures is obtained, start targeted antimicrobial treatment, typically for 2 to 3 weeks.
3. Other drugs are used to treat the underlying condition, if possible. Some patients may benefit from treatment with mucolytics or with bronchodilators (beta2-agonists, anticholinergics).
4. Surgical treatment is used in selected cases; typically partial lung resection (usually including a lobe or several segments) in patients with severe clinical course and bronchiectases located in a limited area, or in the case of a life-threatening hemorrhage. An alternative procedure in the case of hemorrhage is embolization of a bronchial artery.