bronchiectasis

Introduction

Chronic dilation of bronchi or bronchioles as a sequel of inflammatory disease or obstruction.

Etiology

• infection
  • pneumonia (reversible cause)
  • COPD, chronic bronchitis (reversible cause)
  • organisms
    • bacterial
      • tuberculosis (especially affecting upper lobes)
      • Mycobacterium avium complex
      • pertussis as child may lead to bronchiectasis as adult
    • viral
      • adenovirus in adults
      • measles or influenza in children
      • HIV1 infection
    • fungal (chronic mycoses) (affects upper lobes)
      • *histoplasmosis (not typical)
      • coccidioidomycosis
      • allergic bronchopulmonary aspergillosis
  • acute exacerbation
    • Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, Pseudomonas aeruginosa
• ciliary dyskinesia (immotile cilia syndrome)
  • inherited
  • acquired (especially smoking)
• immunoglobulin disorders
  • Bruton's agammaglobulinemia
  • selective IgA deficiency
  • hyperimmunoglobulin E (Job's syndrome)
  • common variable immune deficiency
• HIV1 infection
• right middle lobe syndrome (Mycobacterium avium complex)
• allergic bronchopulmonary aspergillosis (asthma, eosinophilia, high serum IgE)
  • affects upper lobes
  • reversible cause
• yellow nail syndrome
• congenital
  • Young's syndrome
  • Mounier-Kuhn syndrome
• unilateral hyperlucent lung syndrome
• cystic fibrosis (affects upper lobes)
• uncommon causes
  • • alpha-1 antitrypsin deficiency
    • connective tissue diseases
    • rheumatoid arthritis (Felty's syndrome)
    • scleroderma
    • Sjogren's syndrome
    • systemic lupus erythematosus
    • toxic inhalation
    • chronic tracheobronchial stenosis
    • recurrent pulmonary aspiration
    • heroin
    • inflammatory bowel disease
    • ulcerative colitis, Crohn's disease
    • foreign body - asbestosis
    • sequestrated lung
    • chronic tracheoesophageal fistula
    • heart-lung transplantation
    • lung transplantation rejection
    • chronic granulomatous disease
    • chronic hypersensitivity pneumonitis
    • radiation therapy
    • sarcoidosis
    • asthma
    • Marfan syndrome
    • lymphadenpathy
    • neoplasms

Epidemiology

• occurs in both smokers & non-smokers
• non cystic fibrosis patients
  • 79% women, 75% diagnosed age 50-75 years

Pathology

• most commonly occurs in lower lung fields
• in most cases 2nd to 4th order bronchi are involved
• bilateral involvement in 30%
• ~20% of patients with bronchiectasis have eosinophilic inflammation

Clinical manifestations

• chronic productive cough
  • cough not always productive
• sputum
  • frequently purulent, but not necessariy
  • frequently copious
  • may be foul smelling (fetor oris)
  • may be occasionally blood-tinged
• recurrent bronchial infection, pneumonia
  • transient improvement with antibiotics
• sinusitis may be present
• hemoptysis may occur (especially in areas of old tuberculosis)
• coarse rales at lung bases
• clubbing of fingers
• arthralgia
• hypertrophic pulmonary osteoarthropathy
• anorexia & weight loss
• dyspnea common
• wheezing lower lobe (case report, MKSAP20)
  • scattered inspiratory crackles (case report, MKSAP20)
• fatigue common

Laboratory

• sputum cultures yield a mixture of organisms
  • non-tuberculous acid-fast mycobacterium, Mycobacterium avium complex
  • Pseudomonas
• sputum forms layers on standing
• serum IgA, serum IgG, serum IgM
• complete blood count
  • eosinophil count (> 300/uL eosinophilic bronchiectasis)*
• antibodies to Aspergillus
  • Aspergillus IgE in serum
  • Aspergillus IgG in serum

* eosinophil count < 100/uL associated with greater disease severity & mortality

* higher eosinophilic counts were associated with shorter time to exacerbations

Diagnostic procedures

• angiography by interventional radiology for massive hemoptysis
  • 200-1000 mL in 24 hours or > 100 mL in one event
• pulmonary function testing:
  • generally shows obstructive lung disease (50%)
  • 20% with restrictive pattern
• flexible bronchoscopy with bronchoalveolar lavage
  • identify obstruction
  • testing for infections missed by sputum culture
• skin testing for Aspergillus fumigatus (immediate cutaneous reactivity)

Radiology

• chest X-ray
  • may appear normal even with advanced disease
  • patches of increased density at lung bases
  • crowding of bronchi
  • segmental atelectasis
  • honeycombing with cystic spaces measuring < 2.0 cm
  • loss of lung volume
  • air-fluid level (if cystic bronchiectasis is present)
  • 'tram lines' from inciting event, i.e. pneumonia in childhood
  • nodular opacities in right middle lobe
    • Lady Windermere syndrome (Mycobacterium avium complex)
• high-resolution computed tomography (CT) of thorax has replaced bronchography as the diagnostic modality of choice
  • signet-ring shadows
    • dilated bronchus (ring) with bronchial artery (stone)
  • bronchial wall thickening
  • dilated bronchi extending to the periphery
    • airway larger than accompanying blood vessel
    • lack of distal airway tapering
  • bronchial obstruction secondary to inspissated purulent secretions
  • loss of lung volume
  • air-fluid level (if cystic bronchiectasis is present)

Complications

• severe hemoptysis
• progressive respiratory failure with hypoxemia
• cor pulmonale
• secondary infection
  • generally saprophytic infection with fungi &/or mycobacteria
  • Pseudomonas aeruginosa
    • most commonly isolated organism
    • impossible to erradicate
    • infection with Pseudomonas correlates with more extensive disease

Differential diagnosis

• pulmomary emphysema (COPD)
  • multiple sharply defined areas of low attenuation are characteristic of centrilobular emphysema
  • paraseptal emphysema & bullae also in subpleural lung regions
  • obstructive lung disease on spirometry
• bullous lung disease

Management

• determine if underlying treatable cause(s)
  • treat underlying disorders aggressively
• treatment aimed at controlling symptoms, clearing airway, treating infection & preventing exacerbations
  • postural drainage
  • chest physiotherapy
  • humidification
  • acute exacerbations
    • respiratory fluoroquinolone (levofloxacin, moxifloxacin) to ensure coverage for Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, & Pseudomonas aeruginosa for 10-14 days
    • ciprofloxacin may also be used
      • despite its non-respiratory fluoroquinolone status
      • best activity among fluoroquinolones against Pseudomonas aeruginosa
    • use of glucocorticoids not recommended in the absence of asthma or allergic bronchopulmomary aspergillosis
  • in hospital-acquired pneumonia &/or recent antibiotic use (within 90 days) coverage for multi-drug-resistant Pseudomonas & MRSA
    • vancomycin + cefepime, Zosyn or meropenem + fluroquinolone
    • vancomycin + aztreonam or meropenem + fluroquinolone if penicillin allergy
  • cyclic antibiotic therapy
  • daily azithromycin 250 mg results in fewer exacerbations at a cost of antibiotic resistance
    • macrolide maintenance therapy may be associated with fewer cardiovascular events
  • brensocatib reduces activity of neutrophil proteases that contribute to airway inflammation (not yet FDA-approved)
  • no benefit for routine use of bronchodilators
  • no benefit for hypertonic saline nebulizer as an expectorant, or oral carbocisteine to regulate mucous secretion
  • no benefit of long-term systemic glucocorticoids
    • patients with blood eosinophils > 400/uL may benefit from inhaled glucocorticoids
• pulmonary rehabilitation
  • improves exercise capacity
  • reduces emergency department & outpatient visits
• surgery
• lack of evidence-based interventions
• no role for statins

More general terms

• chronic lung disease
• obstructive lung disease

More specific terms

• congenital bronchiectasis

Additional terms

• allergic bronchopulmonary aspergillosis; allergic bronchopulmonary mycosis (ABPA)
• Bruton type agammaglobulinemia
• ciliary dyskinesia; immotile cilia syndrome (Kartagener's syndrome)
• hyperimmunoglobulin E (Job's syndrome)
• right middle lobe syndrome
• selective IgA deficiency
• yellow nail syndrome (lymphedema & yellow nails)
• Young's syndrome (obstructive azoospermia)