Chronic obstructive pulmonary disease

• Chronic obstructive pulmonary disease (COPD) is a group of lung diseases characterised by chronic airflow obstruction, which is not fully reversible.
• Includes chronic bronchitis and emphysema.

1. Toxic particles.
2. Goblet cell hypertrophy.
3. Inflammatory infiltrate.
4. Remodelling.
5. Alveolar destruction.

• Smoking: primary risk factor.
• Biomass fumes (used in heating/cooking).
• Occupational dusts and chemicals.
• Air pollution.
• Genetic causes: α1-antitrypsin deficiency.
• Frequent lower respiratory infections during childhood.

• Chronic productive cough.
• Dyspnoea on exertion, progressing to rest dyspnoea.
• Wheeze and chest tightness.

• Accessory muscle use.
• Tar-stained fingers.
• Tachypnoea.
• Lip pursing.
• Reduced cricosternal distance (<3 fingers).
• Tracheal tug.
• Indrawing of lower intercostal muscles on inspiration.
• Hyper-resonance (with obliterated cardiac and hepatic dullness).
• Quiet breath sounds/wheeze/prolonged expiratory phase.

• Spirometry.
• Chest X-ray: hyperinflated lungs, flat diaphragms, bullae.
• Arterial blood gas: chronic respiratory acidosis and hypoxaemia in advanced stages.
• α1-antitrypsin levels if suspect genetic cause.

• Obstructive pattern: ↓FEV₁ (<80%), normal FVC (>80%), ↓FEV₁/FVC ratio (<0.7)
• Limited reversibility (unlike asthma).
• FEV₁ is also used to grade severity of COPD:
  • Mild (≥80%).
  • Moderate (50-80%).
  • Severe (30-50%).
  • Very severe (<30%).

Inhaled therapy:

Abbreviations: SABA = short-acting β₂ agonist; SAMA = short-acting muscarinic antagonist; LABA = long-acting β₂ agonist; LAMA = long-acting muscarinic antagonist; ICS = inhaled corticosteroid.

Other interventions:

• Stop smoking: prevents progression.
• Pulmonary rehabilitation: exercise and education programme.
• Oxygen therapy: for chronic hypoxaemia.
• Vaccination: annual influenza and pneumococcal vaccines.
• Lung transplant.

• Long-term oxygen therapy: considered in chronic hypoxaemia if PaO2<7.3kPa (or <8kPa in presence of pulmonary hypertension or secondary polycythaemia).
• Ambulatory home oxygen therapy: considered if hypoxaemic on exertion/activity.

• Controlled oxygen aiming 88-92% saturations or PaO2 >8kPa (see prescribing notes on oxygen therapy).
• Salbutamol and Ipratropium nebulisers.
• Prednisolone 30mg OD for 7 days.
• Antibiotics if any signs of infection as per local guidelines, e.g. doxycycline.
• Chest physiotherapy.
• Consider BiPAP in hypercapnic respiratory acidosis not responding to medical management (or if you achieve oxygen sats of 88-92%/PaO2 ≥8kPa without a hypercapnic respiratory acidosis despite medical management).

• Acute exacerbations.
• Respiratory failure.
• Cor pulmonale.
• Secondary polycythaemia.
• Increased risk of lung cancer.
• Pneumothorax.

• COPD includes chronic bronchitis and emphysema. 
• It is characterised by an obstructive pulmonary function pattern, with limited reversibility.
• Clinical features are primarily chronic with possible progression, such as a chronic cough, dyspnoea on exertion and classic clinical signs.
• The main cause of COPD is smoking, so smoking cessation is essential to prevent progression.
• Stepwise management with inhaled therapy is required, alongside lifestyle changes and vaccination.
• Early recognition and appropriate intervention are crucial for acute exacerbations of COPD.

NICE ‘NG115 Chronic obstructive pulmonary disease in over 16s: diagnosis and management’ 2019.