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Pulmonology - Bronchiectasis - Fast Facts | NEJM Resident 360

Bronchiectasis is a descriptor for a number of conditions that lead to structural and anatomic abnormalities in the airways. Specifically, it describes abnormally dilated airways that lead to impaired mucus clearance. Clinically, bronchiectasis manifests as chronic inflammation with recurrent infections and long-term pathogen colonization within the lung.

Normal Lung and Airways and the Lung of a Patient with Bronchiectasis

Normal lung and airways (Panel A) and the lung of patient with bronchiectasis (Panel B)
In Panel B, bronchiectasis is primarily in the lower lobe, which is the most common distribution. The saccular dilatations and grapelike clusters with pools of mucus are signs of severe bronchiectasis.
(Source: Bronchectasis. N Engl J Med 2002.)

Cystic fibrosis is a multisystem genetic disease that manifests primarily as a bronchiectatic lung disease. (Read more on cystic fibrosis in this rotation guide.)

Assessment

Although bronchiectasis is a unifying description for a number of heterogenous diseases, the disease is usually identified and characterized based on imaging with computed tomography (CT).

CT imaging will indicate whether the airways are dilated focally (involving a lobe or section of the lung) or diffusely (involving multiple areas of both lungs), which can help determine the etiology of disease. Approximately one-third of bronchiectasis cases have an unknown etiology (idiopathic bronchiectasis). Examples of conditions associated with diffuse and focal bronchiectasis are listed below:

Diffuse and Focal Conditions Associated with Bronchiectasis

Diffuse Bronchiectasis	Focal Bronchiectasis
Genetic	Infectious
Cystic fibrosis	Severe/necrotizing pneumonia
Kartagener syndrome	Tuberculosis
Alpha1-antitrypsin disease	Focal nontuberculous mycobacterial infection
Primary ciliary dyskinesia	Obstructive
Autoimmune	Foreign body
Rheumatoid arthritis	Mass effect (endobronchial or extrinsic)
Sjögren syndrome
Inflammatory bowel disease
Immunodeficiency/infection
Hypogammaglobulinemia
HIV
Diffuse tuberculosis or nontuberculous mycobacteria
Other
Allergic bronchopulmonary aspergillosis
Yellow nail syndrome

Physical examination: Findings may be limited in bronchiectasis, especially in cases of idiopathic disease. A cough productive of purulent sputum or sinus disease may be present. Lung auscultation may be normal, but crackles, rhonchi, and wheeze are common. Digital clubbing is common in cystic fibrosis but rare in other causes of bronchiectasis.

To address the differential diagnosis, review of other organ systems for signs of autoimmune disease, immunodeficiency, chronic infection, and malignancy is important. 

Investigations

The diagnostic evaluation in bronchiectasis serves two purposes:

1. to confirm and characterize the nature of the bronchiectasis using imaging
2. to determine if there is evidence for an underlying disease that predisposes to the bronchiectasis and modifies management

Imaging

Chest Radiograph of a Patient with Severe Bronchiectasis

A chest radiograph of a patient with diffuse and bilateral bronchiectasis, not caused by cystic fibrosis, manifesting as increased bronchovascular markings with scattered opacities and ring shadows, which represent thickened bronchial walls visualized in transverse cross-section. Bronchiectasis is difficult to characterize on chest x-ray and requires computed tomography. (Image courtesy of George O’Connor, MD.)

CT imaging is required in all patients to characterize the distribution and extent of disease, including the presence of confounding chronic respiratory issues or infection.

CT Images of a Patient with Severe Bronchiectasis

Two axial slices of CT scans from the same patient with diffuse, bilateral bronchiectasis. Abnormalities consistent with the diagnosis of bronchiectasis include an increased bronchoarterial ratio, bronchi visualized within 1 cm of the pleural surface, an absence of typical bronchial tapering, and bronchial wall thickening. (Images courtesy of George O’Connor, MD.)

Pulmonary function testing and the 6-minute walk test are critical to determining pulmonary physiology and functional limitation, respectively.

Laboratory tests: The following blood work can help determine the etiology of disease:

• immunoglobulin quantitation and IgG subclass levels for immunodeficiency

• Aspergillus precipitins and IgE level for allergic bronchopulmonary aspergillosis (ABPA)

• sputum culture and stain for acid-fast bacilli (AFB)

• human immunodeficiency virus (HIV) testing

• rheumatoid factor (RH) and antinuclear antibody (ANA) testing

• alpha₁-antitrypsin level

• cystic fibrosis testing (if otherwise indicated; see section on cystic fibrosis below)

Treatment

Once bronchiectasis has developed, the principles of treatment are similar regardless of the etiology of disease. These principles are similar, but not identical, to management of cystic fibrosis:

• physical therapy (e.g., active cycle breathing, external percussion, cardiovascular exercise) to help sputum clearance

• mucus thinning with inhaled hypertonic saline (but not deoxyribonuclease [DNase])

• smoking avoidance or cessation

• adequate systemic hydration

• seasonal influenza vaccination and dual pneumococcal vaccine (13- and 23-valent)

• chronic antibiotics:

  • Chronic azithromycin therapy is recommended in patients who are not colonized with nontuberculous mycobacteria and who experience more than three exacerbations per year.

  • Chronic antimicrobial therapy with an inhaled antipseudomonal agent (e.g., tobramycin, aztreonam) should be started with the goal of eradication of Pseudomonas aeruginosa. Chronic inhaled therapy should be considered in patients who are colonized with pseudomonas and have three or more exacerbations per year due to a more rapid decline in pulmonary function with this organism.

Etiology-specific treatment: Other therapies may be etiology specific (e.g., immunosuppression for autoimmune disease, prednisone and/or antifungal therapy for ABPA, or intravenous immunoglobulin for immunodeficiency).

Treatment of acute disease: Patients with bronchiectasis are prone to acute infectious exacerbations that require antibiotic therapy and sometimes hospitalization. Symptoms of acute exacerbations are shown below:

Symptoms of Acute Exacerbation of Bronchiectasis
Change in sputum production
Increased dyspnea
Increased cough
Fever (temperature, >38.0°C)
Increased wheezing
Malaise, fatigue, lethargy, or decreased exercise tolerance
Reduced pulmonary function
Radiographic changes consistent with a new pulmonary process
Changes in chest sounds

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