What is bronchiectasis and how is it diagnosed and managed?

Bronchiectasis: Definition, Diagnosis, and Management

Bronchiectasis is a chronic respiratory condition characterized by permanent dilation of the bronchi with destruction of elastic and muscular components of their walls, usually resulting from acute or chronic infection, with the cardinal symptom being chronic productive cough. 1

Definition and Pathophysiology

Bronchiectasis involves three distinct pathogenetic elements that interact with each other:

• Structural changes: Permanent and abnormal widening of the bronchi with destruction of airway wall components 1, 2
• Infection: Chronic or recurrent bacterial colonization, often with pathogens like Haemophilus influenzae and Pseudomonas aeruginosa 1, 3
• Inflammation: Predominantly neutrophilic airway inflammation with excessive inflammatory response 4, 2

This creates a vicious cycle where impaired mucociliary clearance leads to bacterial colonization, triggering inflammation that causes further airway damage and dilation.

Clinical Presentation

• Cardinal symptom: Chronic productive cough with purulent sputum 1
• Other common symptoms:
  • Dyspnea
  • Recurrent respiratory infections
  • Hemoptysis
  • Rhinosinusitis
  • Fatigue
  • Thoracic pain 1

Diagnostic Workup

Imaging

• High-resolution CT (HRCT) scan: The diagnostic gold standard with sensitivity and specificity exceeding 90% 1, 5
  • Key findings:
    • Enlarged internal bronchial diameter (bronchi appear larger than accompanying artery - "signet ring sign")
    • Failure of airways to taper while progressing to lung periphery
    • Bronchial wall thickening
    • Mucoid impaction
    • Air-fluid levels in dilated airways 1

Laboratory Tests

• Sputum culture: To identify pathogens colonizing the airways 1
  • Common organisms: H. influenzae, S. pneumoniae, P. aeruginosa, S. aureus 1
• Blood tests:
  • Elevated C-reactive protein
  • Neutrophilia
  • Elevated inflammatory markers (e.g., IL-6) 5

Pulmonary Function Tests

• Spirometry (may show obstructive, restrictive, or mixed patterns) 1
• Pulse oximetry to screen for respiratory failure 5

Etiologic Workup

Investigate underlying causes:

• Immunodeficiencies (common variable immunodeficiency, X-linked agammaglobulinemia) 6
• Post-infectious (tuberculosis, severe pneumonia, pertussis, measles) 1, 7
• Allergic bronchopulmonary aspergillosis
• Primary ciliary dyskinesia
• Rheumatoid arthritis and other autoimmune conditions
• Inflammatory bowel disease 5

Management

Airway Clearance

• Regular airway clearance techniques are strongly recommended for all patients 5
  • Active cycle of breathing
  • Autogenic drainage
  • Postural drainage
  • Device-assisted methods (flutter, acapella)
  • Performed 1-2 times daily, increasing during exacerbations 5

Antibiotic Therapy

• Acute exacerbations: 14-day course of systemic antibiotics 5

  • First-line: Amoxicillin-clavulanate
  • For P. aeruginosa: Ciprofloxacin (oral) or anti-pseudomonal β-lactam (IV)
  • Adjust based on sputum culture results 1, 5

• Long-term antibiotics for patients with ≥3 exacerbations per year 5

  • Macrolides (azithromycin, erythromycin) preferred
  • Consider inhaled antibiotics for chronic P. aeruginosa infection 5

Mucolytic Therapy

• Hypertonic saline (6-7%) for selected patients with high symptom burden 5
• Note: Recombinant human DNase (rhDNase) is NOT recommended 1, 5

Pulmonary Rehabilitation

• Strongly recommended for patients with impaired exercise capacity 5
• Benefits include improved exercise tolerance and quality of life 5

Immunization

• Annual influenza vaccination
• Pneumococcal vaccination 5

Monitoring and Follow-up

• Outpatient reviews every 3-6 months
• Routine tests: spirometry, sputum culture, pulse oximetry
• Annual assessment, more frequent in severe disease 5

Surgery

• Consider only for localized disease with intolerable symptoms despite maximal medical therapy 1, 5
• Lung transplantation for advanced generalized bronchiectasis 7

Special Considerations

Pseudomonas aeruginosa Infection

• Associated with:
  • More extensive lung lesions
  • More severe impairment of lung function
  • More intense inflammatory response
  • Higher mortality risk (3-fold increase)
  • Higher hospitalization risk (7-fold increase)
  • Average of one additional exacerbation per patient per year 1, 3
• Requires aggressive treatment with ciprofloxacin or anti-pseudomonal β-lactams 1

Non-responding Patients

• 10-20% of patients do not respond to empiric antimicrobial treatment 1
• Causes include:
  • Infection with resistant organisms
  • Nosocomial respiratory infection
  • Non-infectious causes (inadequate medical treatment, embolisms, cardiac failure) 1
• Requires careful microbiological reassessment and antibiotic adjustment 1

Prognosis

• Progressive disease with decline in lung function over time 2
• Age-adjusted mortality rate of 1437.7 per 100,000 1
• Up to 30% mortality at 1-year follow-up after exacerbation, particularly with comorbid COPD 1

By implementing comprehensive management strategies focusing on airway clearance, appropriate antibiotic therapy, and regular monitoring, morbidity and mortality can be reduced and quality of life improved for patients with bronchiectasis.