Chronic Obstructive Pulmonary Disease (COPD)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Patient Advice

Definition

Chronic Obstructive Pulmonary Disease (COPD) is a progressive, non-reversible condition characterised by persistent airflow limitation due to chronic inflammation of the airways and lung parenchyma. It encompasses chronic bronchitis and emphysema.

Aetiology

The main causes of COPD include:

• Smoking: The leading cause of COPD in the UK.
• Air Pollution: Long-term exposure to environmental pollutants.
• Occupational Hazards: Prolonged exposure to dust, chemicals, and fumes.
• Alpha-1 Antitrypsin Deficiency: A genetic cause leading to early-onset COPD.

Pathophysiology

The pathophysiology of COPD involves:

• Chronic Inflammation: Leads to structural changes in the airways and alveoli.
• Airway Obstruction: Narrowing and fibrosis of small airways.
• Alveolar Damage: Loss of elastic recoil and air trapping in emphysema.
• Reduced Gas Exchange: Impaired oxygenation and ventilation-perfusion mismatch.

Risk Factors

Risk factors for COPD include:

• Smoking (active or passive).
• Occupational exposure to irritants.
• Alpha-1 antitrypsin deficiency.
• Frequent respiratory infections in childhood.
• Long-term exposure to indoor biomass fuel (e.g., wood smoke).

Signs and Symptoms

Typical clinical features include:

• Chronic Cough: Often productive with sputum.
• Dyspnoea: Progressive shortness of breath, initially on exertion.
• Wheezing: Due to narrowed airways.
• Frequent Chest Infections: Recurring respiratory tract infections.
• Fatigue: Related to hypoxia and increased work of breathing.

Investigations

Diagnostic tests and findings include:

• Spirometry: Diagnostic test of choice:
  • FEV₁/FVC ratio < 0.7 confirms airflow limitation.
  • FEV₁ reduction classifies disease severity.
• Chest X-ray: May show hyperinflation, flattened diaphragms, or bullae in emphysema.
• Blood Tests:
  • Alpha-1 Antitrypsin Levels: In suspected genetic cases.
  • Full Blood Count: To rule out anaemia or polycythaemia.
• Pulse Oximetry: To assess oxygen saturation.
• Arterial Blood Gas (ABG): For severe or worsening cases to assess hypoxia and hypercapnia.

Management

1. Non-Pharmacological Management

• Smoking Cessation: The most effective intervention to slow disease progression.
• Vaccinations: Annual influenza and pneumococcal vaccines to prevent infections.
• Pulmonary Rehabilitation: Exercise and education programmes to improve function and quality of life.
• Oxygen Therapy: For patients with chronic hypoxia (PaO₂ < 7.3 kPa).

2. Pharmacological Management

• Short-acting Bronchodilators: E.g., salbutamol or ipratropium for symptom relief.
• Long-acting Bronchodilators: E.g., tiotropium or salmeterol for maintenance therapy.
• Inhaled Corticosteroids (ICS): In combination with long-acting beta-agonists (LABA) for severe disease or frequent exacerbations.
• Oral Corticosteroids: For acute exacerbations only.

3. Management of Acute Exacerbations

• Bronchodilators: Increased use of short-acting bronchodilators.
• Systemic Steroids: E.g., prednisolone 30 mg daily for 5 days.
• Antibiotics: For infective exacerbations with purulent sputum (e.g., amoxicillin or doxycycline).
• Hospital Admission: For severe cases requiring oxygen or ventilation.

Patient Advice

Key advice includes:

• Stop smoking and avoid passive smoke exposure.
• Adhere to prescribed inhalers and attend regular follow-up appointments.
• Recognise and act on signs of exacerbations, such as increased breathlessness or changes in sputum.
• Engage in regular physical activity as tolerated.
• Eat a balanced diet to maintain healthy weight.