AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

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).

For excellent patient education resources, visit eMedicine's Procedures Center. Also, see eMedicine's patient education article Bronchoscopy.

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
• a₁-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. A 4-fold higher incidence occurs in American Indians and in Alaskan Native Americans (Redding et al, 2004).

Sex

No sex predilection exists.

Age

In patients with cystic fibrosis, bronchiectasis usually appears in childhood, but its onset may be delayed to adulthood.

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.

• 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.

Clinical Details

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.

Hemoptysis is common and may occur in as many as 50% of patients (Tsao and Lin, 2002). 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 (Edwards et al, 2003). 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.

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% (Hansell, 1998).

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).

DIFFERENTIALS

Section 3 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

Other Problems to be Considered

Lung, abscess
a₁-Antitrypsin deficiency (see Alpha1-Antitrypsin Deficiency)

RADIOGRAPH

Section 4 of 10  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

Findings

Radiography

Chest radiography helps to identify serious disease, and it was once the standard imaging modality. However, the radiographs may depict no abnormalities, or the findings may be nonspecific in patients with less-severe disease.

Various abnormal radiographic findings have been described as follows:

• Parallel line opacities (tram tracks) caused by thickened dilated bronchi
• Ring opacities or cystic spaces as large as 2 cm in diameter resulting from cystic bronchiectasis (see Images 1-2), sometimes with air-fluid levels
• Tubular opacities caused by dilated fluid-filled bronchi (see Images 3-4)
• Increased size and loss of definition of the pulmonary vessels in the affected areas as a result of peribronchial fibrosis (see Image 5)
• Crowding of pulmonary vascular markings from the associated loss of volume, usually caused by mucous obstruction of the peripheral bronchi (see Images 6-7)
• Oligemia as a result of reduction in pulmonary artery perfusion (severe disease)
• Signs of compensatory hyperinflation of the unaffected lung (see Image 1)

Bronchography

Introduced in 1922, bronchography was the investigation of choice until the introduction of HRCT scanning in the mid 1980s. Currently, bronchography is rarely used. Bronchography is performed by instilling contrast material via a catheter or bronchoscope under fluoroscopic control and plain radiographic imaging. The procedure is unpleasant for the patient and is also associated with temporary impairment of ventilation, as well as allergic and foreign body reactions to the contrast medium. In addition, interpretation of bronchographic images is difficult, owing to underfilling and retained secretions.

Degree of Confidence

The accuracy of plain radiographic findings in the diagnosis of bronchiectasis is unknown, because the findings are variable and nonspecific and depend on the severity and extent of the bronchiectasis. However, good correlation exists between the severity of disease as seen on plain images and HRCT scans. Chest radiographic findings may be normal or nonspecific in patients with less-severe disease.

False Positives/Negatives

Many plain radiographic findings are nonspecific and may be seen in patients with idiopathic pulmonary fibrosis, sarcoidosis, histiocytosis X, rheumatoid lung, and other chronic interstitial lung disorders.

CT SCAN

Section 5 of 10  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

Findings

The HRCT imaging technique consists of obtaining 1- to 2-mm collimation scans at 10-mm intervals through the chest with a window level (WL) of –700 Hounsfield units (HU) and a window width (WW) of –1000 HU. The right middle lobe and lingular bronchi cross obliquely and are not optimally depicted on axial HRCT scans; as a result, a gantry angulation of 20° may be required.

HRCT scan findings include the following:

• The internal bronchial diameter may be greater than that of the adjacent artery.
• There may be a lack of bronchial tapering (the same diameter as the parent branch for > 2 cm).
• The bronchi may be within 1 cm of costal pleura or abut the mediastinal pleura (more specific but less sensitive than an increased ratio).
• Bronchial wall thickening may be seen (in 68% of patients).
• A cystic cluster of thin-walled cystic spaces may be present, often with air-fluid levels (see Image 10).
• In cylindrical bronchiectasis, bronchi coursing horizontally are seen as parallel lines, and vertically oriented bronchi are seen as circular lucencies that are larger than the adjacent pulmonary artery (signet-ring appearance) (see Image 11).
• Varicose bronchiectasis may be seen as nonuniform bronchial dilatation.

Other findings include the following:

• Areas of increased and decreased perfusion and attenuation
• Tracheomegaly
• Enlarged mediastinal nodes
• Fluid-filled bronchi are revealed as tubular or branching structures when they course horizontally or are revealed as nodules when they are perpendicular to the plane of the CT scan section (see Image 12).

Degree of Confidence

HRCT scanning has a sensitivity of 96% and a specificity of 93% (Hansell), as compared with bronchography, the previous criterion standard.

Bronchial measurements may vary with the use of different WLs and WWs.

Some patients without bronchiectasis have a 1.49:1 bronchus-to-artery ratio; however, the ratio is reliable only if it is greater than 1.5. If the ratio is less than 1.5, other signs, such as bronchial wall thickening and lack of tapering, should be present for the diagnosis of bronchiectasis.

False Positives/Negatives

The variability of the bronchus-to-artery ratio at high altitudes and in patients with pulmonary hypertension may result in an overdiagnosis because of vasoconstriction in these conditions.

Bronchial wall thickening is optimally seen with a WW of –1000 HU and a WL of –700 HU; higher WL and other WW readings are associated with artifactual wall thickening. This finding is not specific and is also seen in patients with asthma and in those who smoke.

In patients with consolidation, dilated bronchi may not be seen. Cardiac and respiratory artifacts may obscure the results or mimic subtle bronchiectasis in the left lower lobe. Rarely, histiocytosis X and cavitating pulmonary masses mimic cystic bronchiectasis. Traction bronchiectasis occurs in patients with interstitial fibrosis and results from fibrous tethering of the bronchial wall. Traction bronchiectasis is not a true bronchial disorder.

MRI

Section 6 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

Findings

Magnetic resonance imaging (MRI) is not used to evaluate patients with bronchiectasis.

ANGIOGRAPHY

Section 7 of 10  

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• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

Findings

Hemoptysis is symptomatic of a potentially life-threatening condition and warrants urgent and comprehensive evaluation of the lung parenchyma, airways, and thoracic vasculature.

Multidetector-row CT angiography permits noninvasive, rapid, and accurate assessment of the cause and consequences of hemorrhage into the airways and helps guide subsequent management. The combined use of thin-section axial scans and more complex reformatted images allows clear depiction of the origins and trajectories of abnormally dilated systemic arteries that may be the source of hemorrhage and that may require embolization.

Bronchiectasis, chronic bronchitis, lung malignancy, tuberculosis, and chronic fungal infection are some of the most common underlying causes of hemoptysis and are easily detected with CT angiography.

INTERVENTION

Section 8 of 10  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

Bronchial arterial embolization offers an alternative to surgery in select patients with massive or recurrent hemoptysis caused by bronchiectasis, particularly in those patients with cystic fibrosis. In most patients, the hemoptysis originates in the systemic bronchial arteries rather than from the pulmonary arteries.

Selective arteriography of the bronchial arteries is performed to locate the source of the bleeding. In bronchiectasis, bleeding is usually a result of enlarged, dilated bronchial arteries, which are occluded by embolization with use of particulate material larger than the smaller arterioles.

Spinal cord infarction is a potential complication of bronchial artery embolization and arises because the bronchial arteries may communicate with arteries that supply the spinal cord.

Medical/Legal Pitfalls

• Failure to exclude tumor and foreign body obstruction as the cause of bronchiectasis
• Failure to identify and effectively treat allergic bronchopulmonary aspergillosis, atypical mycobacterial infections, immunodeficiency states, and rheumatic diseases
• Failure to recognize complications such as recurrent pneumonia, empyema, and lung abscess

MULTIMEDIA

Section 9 of 10  

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• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

Media file 1:  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.
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Media type:  X-RAY

Media file 2:  This high-resolution computed tomography (HRCT) scan study through the upper lung zones shows extensive bronchiectatic changes (same patient as in Image 1). After several repeat tests, the sweat test demonstrated positive results, and cystic fibrosis was diagnosed.
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Media type:  CT

Media file 3:  This is a close-up radiograph of the left upper lung zone in a 31-year-old woman with chronic cough since childhood. Nodules are present in the left upper lung; the right upper lung was similarly involved.
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Media type:  X-RAY

Media file 4:  The high-resolution computed tomography scan shows thick-walled, slightly ectatic bronchi (same patient as in Image 3). The patient has cystic fibrosis, which was diagnosed in and treated since childhood.
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Media type:  CT

Media file 5:  A 65-year-old woman was examined for chronic cough. The lateral chest radiograph shows overaeration and increased markings over the heart.
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Media type:  X-RAY

Media file 6:  This posteroanterior chest radiograph shows overaeration and somewhat-obscured heart borders (same patient as in Images 5 and 7).
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Media type:  X-RAY

Media file 7:  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). Despite conventional antibiotic treatment, the patient continued to be symptomatic. Eventually, she underwent bronchoscopy, and sampled cultures grew Mycobacterium avium-intracellulare complex.
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Media type:  CT

Media file 8:  A 54-year-old asymptomatic woman with a history of tuberculosis was referred for preoperative chest radiography. The radiograph shows tracheal deviation to the right, an elevated horizontal fissure, and linear lucencies in the partially atelectatic right upper lung; these findings indicate bronchiectasis.
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Media type:  X-RAY

Media file 9:  This lateral chest radiograph shows a partially atelectatic right upper lung (same patient as in Image 8). The patient has tuberculous bronchiectasis, probably caused by fibrosis, the so-called cicatricial bronchiectasis.
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Media type:  X-RAY

Media file 10:  High-resolution computed tomography scan in a 75-year-old man with cystic bronchiectasis.
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Media type:  CT

Media file 11:  This high-resolution computed tomography scan in a 13-year-old female adolescent shows left lower-lobe bronchiectasis, which is secondary to tuberculosis.
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Media type:  CT

Media file 12:  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.
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Media type:  CT

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT SCAN
• Mri
• Angiography
• Intervention
• Multimedia
• References

• 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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• Tsao PC, Lin CY. Clinical spectrum of bronchiectasis in children. Acta Paediatr Taiwan. Sep-Oct 2002;43(5):271-5.
• Webb WR, Muller NL, Naidich DP. High-Resolution CT of the Lung. 2nd ed. Philadelphia, Pa: Lippincott-Raven;1996.
• Westcott JL. Bronchiectasis. Radiol Clin North Am. Sep 1991;29(5):1031-42. [Medline].
• van der Bruggen-Bogaarts BA, van der Bruggen HM, van Waes PF, Lammers JW. Screening for bronchiectasis. A comparative study between chest radiography and high-resolution CT. Chest. Mar 1996;109(3):608-11. [Medline].

Article Last Updated: Dec 8, 2006