Bronchiectasis

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.

(Source: Bronchiectasis. 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.)

Differential Diagnosis

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:

Physical examination: Findings may be limited in bronchiectasis, especially in cases of idiopathic disease. A cough with daily sputum production is the most common symptom. Patients may also report dyspnea, sinusitis, hemoptysis, and pleuritic chest pain. 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.

The diagnostic evaluation in bronchiectasis serves two purposes:

• to confirm and characterize the nature of the bronchiectasis using imaging

• to evaluate for evidence of an underlying disease that predisposes to the bronchiectasis and modifies management

Pulmonary function testing and the 6-minute walk test are critical to determining pulmonary physiology and functional limitation, respectively. Obstructive impairment (e.g., reduced or normal forced vital capacity [FVC], low forced expiratory volume [FEV₁], and low FEV₁/FVC ratio) is the most common finding.

Imaging

Chest Radiograph

(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.

(Images courtesy of George O’Connor, MD.)

Laboratory Tests

The following laboratory results 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 in this rotation guide)

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)

• pulmonary rehabilitation for patients limited by dyspnea

• 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, antifungal therapy, or both 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:

Treatment of advanced disease: Lung resection can be considered in patients with localized disease and whose symptoms are not controlled by optimized medical treatment. Lung transplantation referral should be considered in patients with FEV₁ <30% with clinical instability or rapid progression of symptoms.