COPD

“Syndrome of irreversible airflow obstruction”

Includes sub-types Chronic Bronchitis & Emphysema

Risk Factors

• Modifiable:
  • Smoking (>20 pack year)
• Non-Modifiable:
  • Age (>65)
  • Lower Socioeconomic Status
  • High Pollution Exposure

Aetiology

• Predominantly caused by inhaled toxins
• Genetic predisposition (alpha-1-antitrypsin deficiency)

Pathophysiology

• Chronic Bronchitis:
  • Underlying inflammation
  • Goblet Cells become hyperactive
  • Increased mucous production
  • Causes Inflammatory Oedema
• Emphysema:
  • Oxidative damage occurs, reducing elastic recoil
  • Causes abnormal dilation of airways distal to the terminal bronchioles

Clinical Presentation

• Chronic Bronchitis:
  • Productive cough for >3months for 2 successive years
  • Blue Bloater presentation
    • Central cyansis
    • Reduced exercise tolerance
    • Abnormal auscultation
    • Dyspnea (shortness of breath) at rest
• Emphysema:
  • Pink Puffer presentation
    • CO₂ retention
    • Low body mass
    • Use of accessory inspiratory muscles
    • Barrel chest
    • Pursed lips
    • Non-productive cough

Investigations

• Bloods:
  • Arterial Blood Gas – Chronic type II with decreased O₂ and increased CO₂
• Imaging:
  • Chest X-Ray – Looking for hyperinflated chest or flattened diaphragmatic lines
  • CT scan – Looking for bullae and to rule out other diagnosis
• Special:
  • Spirometry – Is there a low FEV1:FEV ratio (<70%)?
  • Peak Flow
  • Sats – Decreased O₂ sat of 88-92%
  • Sputum sample
• On Examination
  • Increased respiratory rate

Management

• Conservative:
  • Smoking cessation – possible use of Varenicline to aid cessation
• Medical:
  • Combined LABA and LAMA inhalers
  • Combined LABA, LAMA and GCS inhalers
  • Oxygen therapy via Venturi Mask to 88-92% Sat (do not go above 92% to avoid reperfusion damage)
• Surgical:
  • Volume resection – removal of emphysemic tissue to provide space for remaining tissue to expand into

Complications

• COPD Exacerbation (Viral / Bacterial)
• Medication non-compliance
• Malignancy
• Pulmonary Embolism
• Pneumothorax