Bronchiectasis

Introduction

• Abnormal and permanent dilatation of bronchi
• 2/3 of patients are women
• Pathology
  • Destructive and inflammatory changes in walls of medium-sized airways, often at segmental/sub-segmental level
  • Neutrophil-mediated airway inflammation with elastase and matrix metalloprotease release
  • Fibrous replacement of normal tissue components
  • Dilated airways contain pools of thick sputum, with peripheral airway obstruction from secretions or obliterated and replaced by fibrous tissue
  • Vascularity of bronchial walls increases in response to inflammation with enlargement of bronchial arteries and anastomoses between bronchial and pulmonary arterial circulations

Introduction

• Three patterns
  • Cylindrical
    • Bronchi appear uniformly dilated and end abruptly at point where smaller airways are obstructed by secretions
  • Varicose
    • Affected bronchi have irregular or beaded pattern of dilatation
  • Saccular
    • Bronchi have ballooned appearance at the periphery, ending in blind sacs without recognisable bronchial structures distal to these

Aetiology

• Infection is the most common
• Pseudomonas and Haemophilus
• As host defense mechanisms are compromised, bacterial colonisation and growth are aided
• Vicious cycle ensues

Infectious causes

• Adenovirus and influenza are most common viral causes
• Potential necrotising bacterial infections
  • S. aureus, Klebsiella, Anaerobes
• Bordatella pertussis, particularly in childhood, is classically associated with chronic suppurative airways disease
• TB is a major cause worldwide
• Non-tuberculous mycobacteria are often colonisers of bronchiectatic airways, however, MAC can be the primary cause
• Endobronchial obstruction of any cause (e.g. aspirated FB or neoplasm) can lead to chronic bacterial infection and bronchiectasis
• Generalised impairment of host defences
  • Immunoglobulin deficiency e.g. panhypogammaglobulinaemia
  • Primary ciliary dyskinesia (50% have situs inversus – Kartagener’s syndrome)
  • CF with colonisation of Pseudonomas, S. aureus, H. influenzae, E. coli and Burkholderia cepacia

Non-infectious causes

• Inhalation of toxic gas 
• Aspiration of acid gastri contents
• ABPA
• Alpha-1 AT deficiency

Clinical manifestations

• Persistent or recurrent cough and purulent sputum production
• Repeated, purulent respiratory tract infections should raise suspicion
• Haemoptysis occurs in 50-70% of cases
• Systemic fatigue, weight loss and myalgias can occur
• Physical exam
  • Crackles, rhonchi, wheezes, clubbing, cor pulmonale

Diagnosis

• CXR
  • May be normal in mild disease
  • Tram tracks or ring shadows of thickened walls
  • Lumen may appear dense if filled with secretions
• CT (especially HRCT)
  • Standard for diagnosis
• If focal
  • Consider bronchoscopy (for focal endobronchial obstruction) and induced sputum for AFB
• If diffuse
  • Consider CF testing, quantitative immunoglbulin testing, AFB, ciliary function testing, Alpha-1 AT levels, Aspergillus skin and IgE testing, Rheumatic disease serologies and HIV testing

Treatment

• Treat infection, especially acute exacerbations
  • If infrequent exacerbations, only given Ab’s in acute episodes
  • Guided by sputum stain and culture
  • Empirical amoxicillin, bactrim or levofloxacin
  • Pseudomonas associated with greater rate of deterioration in lung function and worse wuality of life
    • Oral quinolone or parenteral aminoglycoside, carbapenem or third-gen cephalosporin are appropriate for 1—14 days
• Improve clearance of secretions
  • Positional drainage, mucolytics may be of benefit
  • Bronchodilators particularly useful if airway hyperreactivity and reversible airflow obstruction evident
  • Aerosolised recombinant Dnase beneficial in CF-related bronchiectasis only
• Reduce inflammation
• Treatment of identifiable underlying problem
• Surgical resection an option if focal disease not responding to medical therapy

Last Updated on October 28, 2020 by Andrew Crofton