Chronic Bronchitis

• Chronic Bronchitis:

  • Defined as a persistent cough with sputum production for at least 3 months of the year for 2 consecutive years
  • Disease of the airways
  • Insidious onset with morning cough (smoker’s cough)
• Chronic Bronchitis:

  • Repeated inhalation of pollutants leads to irritation of the airway mucosa
  • Hyperplasia and hypertrophy of mucus glands in large airway
  • Excessive amounts of mucus in the airways
  • Hyperplasia of goblet cells occurs at the expense of epithelial cilia
• Chronic Bronchitis:

  • Reduced ciliary function
  • Small airways become obstructed by mucus plugs
  • Bacterial colonisation may occur and repeated infections
• Chronic Bronchitis:

  • Small airways become narrowed due to inflammatory changes:
  • mucosal oedema
  • smooth muscle hypertrophy
  • peribronchial fibrosis
• Chronic Bronchitis:

  • Secondary effects of chronic bronchitic airway changes:
  • airway obstruction
  • increased resistance to airflow
  • increased work of breath
  • V/Q mismatch - due to reduced areas of ventilation
  • impaired gas exchange
• Normal airway compared to airway in bronchiolitis:

  
• Aetiology of Chronic Bronchitis:

  • Smoking is the major aetiological factor
  • Environmental pollution
  • Occupational exposure
  • Recurrent bronchial infections
• Chronic Bronchitis - Auscultation:

  • crackle noises
  • created by air going through an airway that's been narrowed e.g. by sputum
• Chest X-ray – Chronic Bronchitis:

  • Patchy shadowing
  • Increased hilar shadowing
  • Increased cardiac shadow - due to right ventricular failure and heart failure