Bronchiectasis

Bronchiectasis is a common cause of chronic productive cough in the UK. It arises from a 'vicious cycle' of impaired mucociliary clearance, bacterial colonisation, and chronic inflammation, leading to irreversible airway damage. Key causes include post-infectious (e.g., severe childhood infections like measles or pertussis, or severe pneumonia), Cystic Fibrosis (CF), Primary Ciliary Dyskinesia (PCD), and immunodeficiencies. Allergic Bronchopulmonary Aspergillosis (ABPA) is an important cause in asthmatics. Patients typically present with a chronic, daily productive cough, often with 'cupfuls' of purulent sputum, and recurrent chest infections. Haemoptysis is also common. On examination, coarse inspiratory crackles, often bibasal, are characteristic and may change after coughing. Finger clubbing can be present in severe or idiopathic cases. High-resolution CT (HRCT) of the thorax is the diagnostic gold standard, revealing bronchial dilatation (often seen as the 'signet ring' sign) and bronchial wall thickening. Sputum microbiology is crucial, as colonisation with organisms like Pseudomonas aeruginosa often indicates a poorer prognosis. Management is multidisciplinary, focusing on daily airway clearance techniques (e.g., chest physiotherapy, oscillatory PEP devices), mucolytics, prompt antibiotic treatment for exacerbations, and sometimes long-term prophylactic antibiotics (e.g., azithromycin). Annual influenza and pneumococcal vaccinations are essential.

The 'vicious cycle' hypothesis (Cole's hypothesis) explains the pathogenesis: an initial insult (e.g., severe infection, genetic defect like CFTR mutation) impairs mucociliary clearance, leading to mucus stasis. This creates a breeding ground for bacteria (e.g., Haemophilus influenzae, Pseudomonas aeruginosa). Bacterial products and the host inflammatory response (especially neutrophil elastase) damage the bronchial wall's elastic and muscular components, causing irreversible dilatation. This further impairs clearance, perpetuating the cycle. In CF, defective CFTR protein leads to thick, dehydrated mucus. In PCD, structural defects in cilia (e.g., dynein arm defects) prevent effective mucus transport. Traction bronchiectasis is a distinct mechanism where surrounding lung fibrosis (e.g., in interstitial lung disease) pulls airways open.

Presentations to look out for: Chronic daily productive cough (often with 'cupfuls' of purulent sputum), recurrent chest infections, haemoptysis (from hypertrophied bronchial arteries), and progressive exertional dyspnoea. Clinical signs: Coarse inspiratory crackles (often bibasal, may clear with cough), wheeze, and finger clubbing (especially in severe or idiopathic cases). Red flags/complications: Type 2 respiratory failure, cor pulmonale, lung abscess, and life-threatening haemoptysis (requiring bronchial artery embolisation). Always consider ABPA in patients with difficult-to-control asthma, fleeting CXR infiltrates, and high eosinophil counts/IgE. In young males with bronchiectasis and infertility, investigate for CF or PCD.

1. **Imaging:**
- **HRCT Thorax:** Gold standard. Look for bronchial wall thickening, lack of bronchial tapering, and the 'signet ring' sign (bronchial lumen diameter > adjacent pulmonary artery diameter). May also show 'tram-track' opacities (thickened bronchial walls).
- **Chest X-ray:** Often non-specific but may show 'tram-track' lines, crowded bronchial markings, or cystic changes. Not sensitive enough for diagnosis.
2. **Microbiology:**
- **Sputum culture:** Essential to identify causative organisms (e.g., H. influenzae, P. aeruginosa, Moraxella catarrhalis, S. aureus, Non-tuberculous Mycobacteria - NTM) and guide antibiotic choice. Sensitivity testing is crucial.
3. **Bloods:**
- **FBC:** May show leukocytosis during exacerbations, eosinophilia in ABPA.
- **Immunoglobulins (IgG, IgA, IgM):** To screen for primary or secondary immunodeficiencies.
- **Total IgE and Aspergillus-specific IgE/RAST:** If ABPA is suspected.
4. **Specialised tests (to identify underlying cause):**
- **Sweat test:** For Cystic Fibrosis (CF).
- **Nasal nitric oxide (nNO):** Low levels suggest Primary Ciliary Dyskinesia (PCD).
- **Genetic testing:** For CFTR mutations (CF) or ciliary gene defects (PCD).
- **Bronchoscopy:** Rarely diagnostic, but may be used to exclude foreign body aspiration or obtain samples if sputum is difficult to produce.

1. **General Measures:**
- **Smoking cessation:** Crucial.
- **Vaccinations:** Annual influenza and pneumococcal vaccine (e.g., Pneumovax II).
2. **Airway Clearance:** Cornerstone of daily management.
- **Chest physiotherapy:** Active Cycle of Breathing Techniques (ACBT), postural drainage.
- **Oscillatory Positive Expiratory Pressure (PEP) devices:** e.g., Acapella, Flutter valve.
- **Mucolytics:** Carbocisteine (reduces sputum viscosity).
- **Nebulised hypertonic saline:** Can improve sputum clearance.
3. **Management of Exacerbations:**
- **Antibiotics:** Guided by sputum culture and sensitivities. Typically 10-14 days. If Pseudomonas is present, Ciprofloxacin is often used. IV antibiotics (e.g., Ceftazidime, Meropenem) may be needed for severe exacerbations or resistant organisms.
4. **Chronic/Prophylactic Antibiotics:**
- **Macrolides (e.g., Azithromycin):** Considered for patients with >=3 exacerbations per year, due to their anti-inflammatory and anti-Pseudomonal effects. Typically given 3 times per week.
5. **Management of Specific Causes:**
- **CF:** CFTR modulators (e.g., Kaftrio), aggressive airway clearance, nutritional support.
- **ABPA:** Oral corticosteroids (e.g., Prednisolone) and antifungal agents (e.g., Itraconazole).
- **Immunodeficiency:** Immunoglobulin replacement therapy.
6. **Surgical:**
- **Lung resection:** For localised disease not responding to medical therapy (rare).
- **Lung transplantation:** For end-stage disease in highly selected young patients.