Chronic Obstructive Pulmonary Disease (COPD)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Referral

Definition

COPD is a progressive lung disease characterised by airflow obstruction that is not fully reversible, commonly caused by smoking. It includes chronic bronchitis and emphysema.

Aetiology

The main causes of COPD are:

• Smoking: the most common cause, accounting for 90% of cases.
• Environmental exposure: long-term exposure to air pollution or occupational irritants (e.g., dust, fumes).
• Alpha-1 antitrypsin deficiency: a genetic condition associated with early-onset COPD.

Pathophysiology

COPD leads to:

• Chronic inflammation of airways.
• Airway narrowing and mucus hypersecretion (chronic bronchitis).
• Alveolar destruction and reduced elastic recoil (emphysema).
• Air trapping and hyperinflation.

Risk factors

• Smoking (active or passive).
• Long-term occupational exposure to dust or fumes.
• Environmental air pollution.
• Genetic predisposition (e.g., alpha-1 antitrypsin deficiency).

Signs and symptoms

Symptoms:

• Persistent cough with sputum production (productive cough).
• Breathlessness (initially on exertion, later at rest).
• Wheeze.
• Frequent respiratory infections.

Signs:

• Prolonged expiration phase.
• Hyperinflated chest ("barrel chest").
• Reduced breath sounds on auscultation.
• Central cyanosis in severe cases.

Investigations

• Spirometry: diagnostic for COPD, showing:
  • FEV₁/FVC ratio <70%.
  • Irreversible airflow obstruction.
• Blood eosinophils:
  • Guide inhaled corticosteroid (ICS) use:
    • ≥0.1 cells/µL: likely to benefit from ICS therapy.
    • <0.1 cells/µL: suggests limited benefit from ICS.
• Chest X-ray: to exclude alternative diagnoses or complications (e.g., lung cancer, infections).
• Alpha-1 antitrypsin levels: if early onset (<45 years) or family history.

Management

Note the follwing management of COPD is based on my local South East London (SEL) guideline and tailored according to exacerbation history and blood eosinophil count. Ensure you follow your local guideline.

Initial Therapy

• For ≤1 moderate exacerbation in the last year:
  • LABA/LAMA:
    • Anoro Ellipta (1 dose daily).
    • Spiriva Respimat (2 doses daily).
    • Duaklir Genuair (1 dose BD).
    • Ultibro Breezhaler (1 dose daily).
• For ≥2 moderate exacerbations or ≥1 severe exacerbation:
  • ICS/LABA & LAMA:
    • Trimbow NEXThaler 88/5/9 (2 doses BD).
    • Trelegy Ellipta 92/55/22 (1 dose daily).
    • Trimbow pMDI 87/5/9 (2 doses BD via spacer).

General Recommendations:

• Encourage smoking cessation, this is the most effective intervention to slow disease progression.
• Offer annual influenza and pneumococcal vaccinations.
• Optimise inhaler technique and adherence.
• Consider pulmonary rehabilitation for symptomatic patients and if their Medical Research Council (MRC) score is 3 or higher.

Referral

• Urgent referral: If severe respiratory distress, significant hypoxia, or possible alternative diagnoses like lung cancer.
• Specialist referral:
  • Recurrent exacerbations despite optimised treatment.
  • Assessment for long-term oxygen therapy.
  • Consideration of alpha-1 antitrypsin therapy.