Bronchiectasis

Overview

Bronchiectasis is defined by the permanent, abnormal dilation of one or more bronchi resulting from destruction of the bronchial wall. Unlike transient airway changes seen with acute infection, the structural damage in bronchiectasis is irreversible. The disease manifests clinically as a chronic daily productive cough with mucopurulent sputum, recurrent pulmonary exacerbations, and — in some patients — hemoptysis and progressive dyspnea.

This guide focuses on non-CF bronchiectasis. Cystic fibrosis is the most well-known cause of bronchiectatic airways but involves distinct management principles and is addressed in its own guide. The non-CF form is a heterogeneous condition with many possible underlying etiologies, and identifying the cause has direct implications for treatment.

For respiratory therapists, bronchiectasis demands a daily commitment to airway clearance. The goal is not cure but cycle interruption: break the feedback loop of mucus retention and infection before it drives further structural damage.

Key Concepts

The Vicious Cycle of Bronchiectasis

The central pathophysiologic concept is sometimes called the “vicious cycle” or “vicious vortex.” Impaired mucociliary clearance allows secretions to accumulate in the airways. Retained mucus creates an ideal environment for bacterial colonization and chronic infection. The resulting neutrophilic inflammation releases proteases and reactive oxygen species that destroy the bronchial wall — elastin, cartilage, and smooth muscle — causing the airway to dilate. Dilated, damaged airways clear secretions even less efficiently, perpetuating the cycle. Understanding this loop explains why airway clearance is not optional: it is the only intervention that directly targets the initiating step.

Etiologies

A wide range of conditions can initiate the vicious cycle by damaging the airway or impairing clearance:

• Post-infectious: Severe pneumonia (including childhood pneumonia), tuberculosis, pertussis, and measles can all cause permanent airway injury.
• Cystic fibrosis: The classic genetic cause; covered separately.
• Primary ciliary dyskinesia (PCD): Structural defects in cilia impair mucociliary transport from birth.
• Immunodeficiency: Recurrent infections in patients with hypogammaglobulinemia or other antibody deficiencies.
• Allergic bronchopulmonary aspergillosis (ABPA): A hypersensitivity response to Aspergillus that causes central bronchiectasis.
• COPD overlap: Bronchiectasis and COPD frequently coexist and share risk factors.
• Aspiration and autoimmune disease (e.g., rheumatoid arthritis, Sjögren’s syndrome) are additional recognized causes.
• Idiopathic: Despite thorough workup, no underlying cause is identified in a significant proportion of patients.

Microbiology

Haemophilus influenzae is the most frequently isolated pathogen in milder or earlier-stage disease. Pseudomonas aeruginosa colonization is a marker of more severe disease and is associated with faster decline and more frequent exacerbations. Nontuberculous mycobacteria (NTM), particularly the Mycobacterium avium complex, are increasingly recognized, and their presence has critical implications for antibiotic management (see below).

Assessment & Findings

Symptoms

• Chronic daily productive cough — the most consistent symptom; sputum is typically mucopurulent or purulent.
• Recurrent pulmonary exacerbations characterized by increased sputum volume or purulence, worsening dyspnea, and sometimes fever.
• Hemoptysis — ranges from blood-streaked sputum to massive hemorrhage; always prompts urgent evaluation.
• Progressive dyspnea on exertion as lung function declines.

Physical Examination

• Crackles (coarse, inspiratory) over affected lobes are the most common finding.
• Wheeze may be present, particularly if there is COPD overlap or reactive airways disease.
• Digital clubbing occurs in some patients, especially those with long-standing severe disease.

Diagnosis: HRCT

High-resolution CT (HRCT) of the chest is the gold standard for diagnosis and replaces the need for bronchography. Key findings include:

• Signet-ring sign: The bronchial internal lumen is wider than the diameter of the adjacent pulmonary artery — the hallmark of bronchiectasis on CT.
• Tram-track lines: Parallel bronchial walls seen in cross-section indicating bronchial wall thickening and dilation.
• Lack of normal tapering: Airways fail to taper as they progress toward the periphery.
• Mucus plugging: Retained secretions visible within dilated airways.

Pulmonary Function & Microbiology

Spirometry typically shows an obstructive pattern, though a mixed or restrictive defect is possible when disease is widespread. Sputum culture is essential: it guides antibiotic selection during exacerbations, identifies Pseudomonas colonization warranting inhaled antibiotic therapy, and — critically — must exclude NTM before long-term macrolide therapy is initiated.

RT Priorities / Interventions

1. Daily Airway Clearance (the Cornerstone)

For patients with chronic productive disease, daily airway clearance therapy (ACT) is the most important intervention. Multiple modalities are effective; patient adherence and preference should guide selection:

• Oscillatory positive expiratory pressure (oscillatory PEP): Devices such as Acapella or Flutter generate oscillations that loosen secretions and stent airways open during exhalation.
• Active cycle of breathing technique (ACBT): Breathing control → thoracic expansion exercises → forced expiration technique (huff coughing) performed in sequence.
• Autogenic drainage: A self-managed technique using tidal breathing at controlled lung volumes to collect and move secretions centrally.
• Postural drainage: Positioning the patient to use gravity to drain specific bronchopulmonary segments; often combined with percussion or vibration.
• High-frequency chest-wall oscillation (HFCWO): Inflatable vest that delivers rapid oscillations to the chest wall to mobilize secretions.

For a detailed comparison of techniques and positioning protocols, see the airway clearance guide.

2. Mucoactive Therapy

Nebulized hypertonic saline(typically 6–7%) is the preferred mucoactive agent in non-CF bronchiectasis. It draws water into the airway lumen, hydrates secretions, and enhances mucociliary clearance. It is typically administered before airway clearance sessions to optimize sputum mobilization.

Dornase alfa is NOT recommended in non-CF bronchiectasis.Clinical trial data showed it can worsen disease and increase exacerbation frequency in non-CF patients. This is a common and potentially harmful error — see Common Pitfalls below.

3. Long-Term Macrolide Therapy

In patients with frequent exacerbations despite optimized ACT, long-term azithromycin (e.g., 250–500 mg three times weekly) reduces exacerbation frequency. Its benefit is primarily anti-inflammatory and immunomodulatory rather than antibacterial. However, NTM infection must be excluded by sputum culture before initiation— azithromycin monotherapy rapidly selects for macrolide-resistant NTM strains, which are extremely difficult to treat.

4. Inhaled Antibiotics

For patients with confirmed chronic Pseudomonas aeruginosa colonization, inhaled antibiotics (e.g., tobramycin, aztreonam, colistin) are used to suppress bacterial burden and reduce exacerbation frequency. Systemic eradication of Pseudomonas should be attempted at first isolation.

5. Exacerbation Management

Acute exacerbations are treated with intensified airway clearance (increasing frequency from once to two to four times daily) combined with culture-directed systemic antibiotics for approximately 14 days. Pseudomonas exacerbations typically require an antipseudomonal beta-lactam or fluoroquinolone. Pulmonary rehabilitation improves exercise capacity and quality of life and is recommended as an adjunct during the stable phase and after exacerbations.

Common Pitfalls

• Using dornase alfa in non-CF bronchiectasis.This is the most clinically important error. Dornase alfa is a CF-specific therapy that is contraindicated in non-CF bronchiectasis — it has been shown to increase exacerbations. Verify the diagnosis before prescribing any mucoactive agent.
• Starting long-term azithromycin without first excluding NTM. Macrolide monotherapy in a patient with occult NTM infection induces resistance that eliminates the most effective drugs from the treatment armamentarium. Sputum cultures (at least two to three specimens) should be sent and reviewed before initiating chronic macrolide therapy.
• Treating bronchiectasis as COPD and omitting daily airway clearance. COPD management does not include structured ACT. Patients whose bronchiectasis presents with obstruction may be mismanaged with bronchodilators alone. The daily clearance regimen is non-negotiable in productive bronchiectasis.
• Under-recognizing Pseudomonas as a severity marker. Isolating P. aeruginosafrom sputum is not merely a microbiologic curiosity — it signals a shift to more aggressive disease requiring targeted therapy, closer monitoring, and referral to a bronchiectasis specialist center if not already done.
• Failing to identify and treat an underlying cause. A correctable etiology (e.g., hypogammaglobulinemia amenable to immunoglobulin replacement, ABPA responsive to antifungal therapy) may dramatically change the disease course if identified and treated. A structured etiologic workup should be completed in all new diagnoses.

Board Exam Pearls

• The signet-ring sign on HRCT — bronchial lumen wider than the accompanying pulmonary artery — is the hallmark diagnostic finding for bronchiectasis.
• The vicious cycle/vortex (impaired clearance → infection → inflammation → airway damage → worse clearance) is the central pathophysiologic concept and the justification for daily ACT.
• Dornase alfa benefits CF but is contraindicated in non-CF bronchiectasis — this distinction appears frequently on board examinations.
• Airway clearance + nebulized hypertonic saline are the mainstays of stable-disease management.
• Exclude NTM before starting chronic macrolide therapy to avoid inducing resistance that eliminates future treatment options.
• Pseudomonas aeruginosa colonization marks more severe disease and warrants inhaled antibiotic therapy.
• Common post-infectious causes include tuberculosis, pertussis, and measles — all associated with childhood infections that cause permanent airway damage.

FAQ

Related Resources

Sources

1. Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021.
2. Polverino E, Goeminne PC, McDonnell MJ, et al. European Respiratory Society guidelines for the management of adult bronchiectasis. Eur Respir J. 2017;50(3):1700629.
3. Hill AT, Sullivan AL, Chalmers JD, et al. British Thoracic Society guideline for bronchiectasis in adults. Thorax. 2019;74(Suppl 1):1-69.