Introduction
Background
Bronchiectasis is defined as localized irreversible dilatation of part of the bronchial tree. Involved bronchi are dilated, inflamed, and easily collapsible, resulting in airflow obstruction and impaired clearance of secretions. Bronchiectasis is associated with a wide range of disorders (see Diseases associated with bronchiectasis in the Pathophysiology section, below), but it usually results from necrotizing bacterial infections, such as infections caused by the Staphylococcus or Klebsiella species or Bordetella pertussis. Diagnosis is based on a clinical history of daily viscid sputum production and characteristic computed tomography (CT) scanning findings (see CT Scan).
A 27-year-old man diagnosed with reactive airway disease as a child was examined because of frequent respiratory infections. The posteroanterior chest radiograph shows ill-defined pulmonary nodular opacities, mild scoliosis, and moderate overaeration.
High-resolution computed tomography scan in a 75-year-old man with cystic bronchiectasis.
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Pathophysiology
By definition, bronchiectasis demonstrates localized, irreversible dilatation of bronchi > 2 mm in diameter that results from destruction of the muscular and elastic components of bronchial walls. Damage to these 2 bronchial wall components is caused by an infectious organism and also by the inflammatory cytokines, nitric oxide, and neutrophilic proteases released by the host's immune response to the organism. Additionally, peribronchial alveolar tissue may be damaged, resulting in diffuse peribronchial fibrosis. The result is abnormal bronchial dilatation with bronchial wall destruction and transmural inflammation. The involved bronchi are not only dilated but also inflamed and easily collapsible, resulting in airflow obstruction and impaired clearance of secretions.
The most important functional finding of altered airway anatomy is severely impaired clearance of secretions from the bronchial tree. This altered airway anatomy causes colonization and infection with pathogenic organisms, contributing to the common purulent expectoration observed in patients who have bronchiectasis. The result is a cycle of bronchial damage, bronchial dilatation, impaired clearance of secretions, recurrent infection, and more bronchial damage.
Diseases associated with bronchiectasis are as follows:
- Infection: Typical organisms include Klebsiella species, Staphylococcus aureus, Mycobacterium tuberculosis, Mycoplasma pneumoniae, nontuberculous mycobacteria, Mycobacterium avium-intracellulare complex, measles, pertussis, influenza, respiratory syncytial virus, herpes simplex virus, and certain types of adenovirus.
- Bronchial obstruction: Obstruction occurs as a result of endobronchial tumors, broncholithiasis, bronchial stenosis resulting from infections, encroachment of hilar lymph nodes, and foreign body aspiration.
- Cystic fibrosis
- Young syndrome
- Primary ciliary dyskinesia
- Allergic bronchopulmonary aspergillosis
- Immunodeficiency states: The most common congenital conditions involve B-lymphocyte functions—specifically, hypogammaglobulinemia. An aggressive form of bronchiectasis has been described in patients with acquired immunodeficiency syndrome (AIDS).
- Congenital anatomic defects
- Bronchopulmonary sequestration
- Williams-Campbell syndrome (congenital cartilage deficiency)
- Mounier-Kuhn syndrome (tracheobronchomegaly)
- Swyer-James syndrome (unilateral hyperlucent lung)
- Yellow nail syndrome
- a 1 -Antitrypsin deficiency
- Lung and bone marrow transplants
- Rheumatoid arthritis and Sjögren syndrome
- Traction bronchiectasis associated with pulmonary fibrosis
Frequency
United States
The incidence of bronchiectasis declined after the introduction of immunizations (pertussis) and antibiotics. The exact overall incidence is not known because the symptoms are not specific, and minor forms often remain undiagnosed. The prevalence is highest among persons in lower socioeconomic groups.
International
Bronchiectasis is an important cause of morbidity in underdeveloped countries. Its incidence has diminished in developed countries, but it is still an important cause of morbidity, especially in children.
Mortality/Morbidity
- Mortality is related to progressive respiratory failure and cor pulmonale rather than to uncontrolled infection. Hemoptysis is common but rarely causes death.
- Complications include recurrent pneumonia, empyema, pneumothorax, and lung abscess. Amyloidosis and metastatic abscesses, common causes of morbidity and mortality in the preantibiotic era, are now uncommon.
Race
No racial predilection exists. There is a 4-fold higher incidence in American Indians and Alaskan Native Americans.1
Sex
No sex predilection exists.
Age
In patients with cystic fibrosis, bronchiectasis usually appears in childhood, but its onset may be delayed to adulthood.2
Anatomy
Bronchiectasis usually involves bronchi of medium size (>2 mm diameter). The proximal (main, lower, and segmental) bronchi are less affected, because they contain more cartilage than the distal bronchi and because they are more resistant to dilation. However, in patients with allergic bronchopulmonary aspergillosis and cystic fibrosis, the proximal bronchi are typically involved.
Although bronchiectasis caused by bacterial and viral infections usually affects the lower pulmonary lobes, the upper lobes are more frequently affected in patients with allergic bronchopulmonary aspergillosis and tuberculosis. Bronchiectasis is more diffuse in patients with cystic fibrosis and those with immunodeficiency states.
In advanced cases of bronchiectasis, dilated, medium-sized bronchi extend close to the pleura, without side branches and with few normal surrounding lung parenchyma. Focal destruction of part of the bronchial wall, increased mucus secretion and retention, and peribronchial fibrosis occur; the surrounding lung shows volume loss, fibrosis, emphysema, and nodular inflammatory foci.
In 1950, Reid classified bronchiectasis as cylindrical, cystic, or varicose.3
- In cylindrical bronchiectasis, bronchi have a uniform caliber, they do not taper, and they have parallel walls.
- Cystic or saccular bronchiectasis is a severe form of bronchiectasis. The involved bronchi are cystlike in appearance and extend to the pleural surface. Air-fluid levels are commonly present.
- Varicose bronchiectasis is relatively uncommon. The bronchi have a beaded appearance with a dilated bronchus and interspersed sites of relative narrowing.
Presentation
History
The classic triad of symptoms (chronic cough, excess purulent sputum production, repeated infections) is seen only in the most severely affected patients. Total daily sputum production has been used to characterize severity of bronchiectasis:
- 10 mL/d is defined as mild bronchiectasis.
- 10-150 mL/d is defined as moderate bronchiectasis.
- 150 mL/d is defined as severe bronchiectasis.
Many patients have only mild or intermittent symptoms. Some patients with mild forms of bronchiectasis, as revealed on high-resolution computed tomography (HRCT) scans, may have no symptoms.4
Hemoptysis is common and may occur in as many as 50% of patients.5 Episodic hemoptysis with little to no sputum production (dry bronchiectasis) is usually a sequela of tuberculosis. However, massive hemoptysis may occur; bleeding usually originates in dilated bronchial arteries, which contain blood at systemic (rather than pulmonary) pressures.
Less-specific symptoms include dyspnea, pleuritic chest pain, wheezing, fever, weakness, and weight loss. Significant airway obstruction may occur as a result of the bronchitis, bronchiolitis, or emphysema that frequently accompanies bronchiectasis. Repeated bronchial infection and pneumonia are common.
Physical examination
Findings are nonspecific and may be attributed to other conditions. On auscultation, crackles, rhonchi, wheezing, and inspiratory squeaks may be detected. Digital clubbing is reported in 37-51% of patients with bronchiectasis.6 Edwards and colleagues found that children with digital clubbing and chest deformity showed significantly higher scores for the extent of their bronchiectasis, bronchial wall dilatation and thickness, and overall changes based on CT scanning scores. Cyanosis, plethora, wasting, weight loss, nasal polyps, and signs of chronic sinusitis may be present. In patients with advanced disease, signs of cor pulmonale may be detected.
Preferred Examination
Chest radiography is usually the first imaging examination, but the findings are often nonspecific and the images may appear normal. HRCT scanning has become the imaging modality of choice for demonstrating or ruling out bronchiectasis and its extent (see Image 2, Image 4, Image 7, Images 10-12). HRCT scanning also helps clinicians evaluate the status of the surrounding lung tissue and exclude other lesions such as neoplasms.7
A 27-year-old man diagnosed with reactive airway disease as a child was examined because of frequent respiratory infections. The posteroanterior chest radiograph shows ill-defined pulmonary nodular opacities, mild scoliosis, and moderate overaeration.
This high-resolution computed tomography (HRCT) scan study through the upper lung zones shows extensive bronchiectatic changes (same patient as in Image above). After several repeat tests, the sweat test demonstrated positive results, and cystic fibrosis was diagnosed.
The high-resolution computed tomography scan shows thick-walled, slightly ectatic bronchi (same patient as in Image 3 in Multimedia). The patient has cystic fibrosis, which was diagnosed in and treated since childhood.
This high-resolution computed tomography scan through the upper lung zone of the right side demonstrates bronchiectatic changes (same patient as in Images 5 and 6 in Multimedia). Despite conventional antibiotic treatment, the patient continued to be symptomatic. Eventually, she underwent bronchoscopy, and sampled cultures grew Mycobacterium avium-intracellulare complex.
High-resolution computed tomography scan in a 75-year-old man with cystic bronchiectasis.
The high-resolution computed tomography scan demonstrates findings of fluid-filled dilated bronchi in a 65-year-old man with bronchiectasis in the left lower lobe.
Bronchography was the classic modality used and, until the advent of HRCT scanning, was the only imaging method to demonstrate bronchiectasis. Bronchography is performed by instilling an iodine-based contrast material via a catheter or bronchoscope, but it is rarely, if ever, performed today, as HRCT scanning has replaced it as the diagnostic modality of choice. HRCT scanning is noninvasive and has a sensitivity of 96% and a specificity of 93%.8
Laboratory testing may be helpful:
- Results of sputum culture and analysis may reinforce the diagnosis of bronchiectasis and add significant information regarding potential etiologies.
- Complete blood counts are often abnormal in patients who have bronchiectasis.
- Quantitative immunoglobulin (Ig) levels, including levels of the IgG subclasses, IgM, and IgA, are used to exclude hypogammaglobulinemia.
- Quantitative a1 -antitrypsin levels are used to exclude deficiency.
- Pilocarpine iontophoresis (sweat testing) is used to detect cystic fibrosis.
- Pulmonary function test results may be normal or abnormal but can be useful in making a functional assessment of the patient. The most common abnormality is an obstructive airway defect.
Bronchoscopy is not helpful in diagnosing bronchiectasis, but it may be used to identify underlying abnormalities, such as tumors and foreign bodies.
Limitations of Techniques
Chest radiographs may be negative in patients with minor to moderate disease. Many abnormal radiographic findings may be nonspecific, and confirmation using HRCT scanning may be required (see Radiograph).
Bronchography is rarely indicated (see Radiograph) because it is invasive and is associated with allergic reactions to the contrast material. Bronchography also carries the risk of acute bronchoconstriction.
HRCT scanning is the diagnostic modality of choice and has few limitations (see CT Scan).
Differential Diagnoses
Other Problems to Be Considered
Lung, abscess
a 1 -Antitrypsin deficiency (see Alpha1-Antitrypsin Deficiency)
More on Bronchiectasis |
 Overview: Bronchiectasis |
| Imaging: Bronchiectasis |
| Follow-up: Bronchiectasis |
| Multimedia: Bronchiectasis |
| References |
| Further Reading |
| Next Page » |
References
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Redding GJ. Bronchiectasis in Children. Pediatr Clin North Am. Feb 2009;56(1):157-171. [Medline].
Reid LM. Reduction in bronchial subdivision in bronchiectasis. Thorax. Sep 1950;5(3):233-47. [Medline].
King PT, Holdsworth SR, Freezer NJ, et al. Characterisation of the onset and presenting clinical features of adult bronchiectasis. Respir Med. Dec 2006;100(12):2183-9.
Tsao PC, Lin CY. Clinical spectrum of bronchiectasis in children. Acta Paediatr Taiwan. Sep-Oct 2002;43(5):271-5.
Edwards EA, Metcalfe R, Milne DG, et al. Retrospective review of children presenting with non cystic fibrosis bronchiectasis: HRCT features and clinical relationships. Pediatr Pulmonol. Aug 2003;36(2):87-93.
Failo R, Wielopolski PA, Tiddens HA, Hop WC, Pozzi Mucelli R, Lequin MH. Lung morphology assessment using MRI: A robust ultra-short TR/TE 2D steady state free precession sequence used in cystic fibrosis patients. Magn Reson Med. Jan 22 2009;61(2):299-306. [Medline].
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Bruzzi JF, Remy-Jardin M, Delhaye D, et al. Multi-detector row CT of hemoptysis. Radiographics. Jan-Feb 2006;26(1):3-22.
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Fraser RS, Muller NL, Colman NC, Pare PD. Bronchiectasis and other bronchial abnormalities. In: Fraser RS, Muller NL, Colman NC, et al, eds. Fraser and Pare's Diagnosis of Diseases of the Chest. 4th ed. Philadelphia, Pa: WB Saunders;1999: 2265-97.
Grenier PA, Beigelman-Aubry C, Fetita C, et al. New frontiers in CT imaging of airway disease. Eur Radiol. May 2002;12(5):1022-44. [Medline].
Joharjy IA, Bashi SA, Adbullah AK. Value of medium-thickness CT in the diagnosis of bronchiectasis. AJR Am J Roentgenol. Dec 1987;149(6):1133-7. [Medline].
McGuinness G, Naidich DP. CT of airways disease and bronchiectasis. Radiol Clin North Am. Jan 2002;40(1):1-19. [Medline].
Naidich DP. High-resolution computed tomography of cystic lung disease. Semin Roentgenol. Apr 1991;26(2):151-74. [Medline].
Pifferi M, Caramella D, Bulleri A, et al. Pediatric bronchiectasis: correlation of HRCT, ventilation and perfusion scintigraphy, and pulmonary function testing. Pediatr Pulmonol. Oct 2004;38(4):298-303.
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Swanson KL, Johnson CM, Prakash UB, et al. Bronchial artery embolization: experience with 54 patients. Chest. Mar 2002;121(3):789-95. [Medline]. [Full Text].
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Further Reading
Related eMedicine topics
Bronchiectasis (from Pulmonology)
Bronchiectasis (from Pediatrics: General Medicine)
Pneumonia, Bacterial
Pneumonia, Viral
Chronic Obstructive Pulmonary Disease
Clinical guidelines
Chronic Cough due to Bronchiectasis: ACCP Evidence-Based Clinical Practice Guidelines
Pulmonary Rehabilitation: Joint ACCP/AACVPR Evidence-Based Clinical Practice Guidelines
Clinical studies
Efficacy of Budesonide-Formoterol in Bronchiectasis
Airway Clearance in Bronchiectasis: is Non-Invasive Ventilation a Useful Adjunct in Moderate to Severe Disease?
Keywords
bronchiectasis, bronchial tree disease, pulmonary disease, abnormal dilatation of bronchi, pulmonary infections, cystic fibrosis, Young syndrome, primary ciliary dyskinesia, allergic bronchopulmonary aspergillosis, hypogammaglobulinemia, bronchopulmonary sequestration, Williams-Campbell syndrome, Mounier-Kuhn syndrome, Swyer-James syndrome, yellow nail syndrome, rheumatoid arthritis, Sjögren syndrome
