Understanding Chronic Obstructive Pulmonary Disease

Sep 3, 2024

Chronic Obstructive Pulmonary Disease (COPD)

Overview

  • Definition: COPD is a condition where airways in the lungs become inflamed and narrowed, and air sacs (alveoli) become damaged.
  • Common Cause: Primarily caused by smoking cigarettes (active or passive).
  • Impact: Increased difficulty in breathing over time due to lung damage.

Pathophysiology

  • Normal Air Passage: Air travels from nose/mouth to air sacs (alveoli) where oxygen and carbon dioxide exchange occurs.
  • Risk Factors:
    • Smoking
    • Air pollution
    • Workplace dust/organic materials
    • Genetic condition: Alpha-1 antitrypsin deficiency
  • Pathological Processes:
    1. Loss of alveolar attachments
    2. Inflammatory obstruction of airways
    3. Luminal obstruction with mucus production
  • Chronic Inflammation: Leads to airway scarring and lung tissue damage.

Forms of COPD

  1. Chronic Bronchitis:

    • Defined as productive cough with sputum for at least 3 months/year for 2 consecutive years.
    • Associated with bronchial inflammation, often in smokers.
    • Classically known as Blue Bloaters:
      • Overweight
      • Productive cough
      • Side-nosed, dyspneic, potential core pulmonale.

  2. Emphysema:

    • Damage to the alveoli leading to airflow restriction and gas trapping.
    • Classically known as Pink Puffers:
      • Cachectic
      • Dyspneic
      • Hyperinflated lungs (barrel chest).

Diagnosis

  • Investigations:
    • Pulmonary function test (FEV/FVC ratio < 70%)
    • Chest X-ray (hyperinflated lungs)
    • CT chest (best for diagnosing emphysema)
    • ECG (check for pulmonary hypertension)
    • Arterial blood gas analysis (oxygen, carbon dioxide, bicarbonate levels)

Management

Non-Pharmacological

  • Vaccination updates
  • Smoking cessation
  • Avoiding triggers
  • Action plans for acute exacerbations
  • Pulmonary rehabilitation
  • Oxygen therapy for end-stage COPD

Pharmacological

  • Bronchodilators:
    • Short-acting and Long-acting
    • Classes:
      • Beta-2 adrenergic agonists: Promote bronchodilation.
      • Muscarinic antagonists: Prevent bronchoconstriction.
  • Combination Therapy: Often involves a mix of short-acting, long-acting, and inhaled corticosteroids.
  • For severe cases, theophylline may be added.

Surgical Options

  • Bulectomy: Removal of air-filled sacs in the lung.
  • Lung Volume Reduction Surgery
  • Rarely, single lung transplant.

Management of Acute Exacerbations

  • Investigations:
    • Blood tests
    • Chest X-ray
  • Treatment Goals:
    • Achieve appropriate oxygen saturation
    • Short-acting bronchodilators
    • Steroids (IV/oral)
    • Antibiotics if bacterial infection is suspected
    • Non-invasive ventilation

Summary

  • COPD causes airway inflammation, narrowing, and air sac damage.
  • Two main forms: emphysema and chronic bronchitis (with overlap).
  • Treatment involves bronchodilators (short and long-acting) and inhaled corticosteroids.