Bronchitis and Bronchiolitis

Bronchitis and Bronchiolitis

• Bronchitis is an inflammatory condition of the large elements of the tracheobronchial tree, affecting older children and adults.
• Bronchiolitis is an inflammatory condition of the small elements of the tracheobronchial tree, mostly affecting infants during their first year of life.

Bronchitis Pathophysiology

• Infection of the trachea and bronchi leads to hyperemic and edematous membranes, increased bronchial secretions, and damage to the respiratory epithelium.
• Chronic inhalation of an irritating substance compromises the normal secretory and mucociliary function of bronchial mucosa, leading to thickening of the bronchial wall.
• Increased desquamated epithelial cells and bronchial secretions may impair mucociliary actions, and goblet cells in smaller bronchi produce more mucus.

Bronchitis: Most Common Pathogens

• Viruses are the most common cause of acute bronchitis, including rhinovirus, coronavirus, influenza virus, and adenovirus.
• Bacterial causes of acute bronchitis include Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Bordetella pertussis.
• Acute exacerbations of chronic bronchitis are often caused by H. influenzae, M. catarrhalis, S. pneumonia, and Gram-negative pathogens.
• Secondary bacterial infections may occur after a viral infection.

Clinical Presentation: Acute Bronchitis

• Symptoms include nonproductive cough early, followed by productive mucopurulent sputum, and fever is rare.
• Purulent sputum is off-white, yellow, or green, and opaque, indicating the presence of large numbers of white blood cells.
• Red coloration of sputum is usually due to its mixture with blood.
• More pronounced symptoms occur in patients with underlying lung disease.

Clinical Presentation: Chronic Bronchitis

• Mild to moderate cough with increased sputum production for at least 3 consecutive months for 2 years is characteristic of chronic bronchitis.
• Simple chronic bronchitis is diagnosed when there are no major risk factors and sputum flora reflects the common associated pathogens.
• Complicated chronic bronchitis is described when patients have two or more disease-associated risk factors, including FEV1, home oxygen use, underlying cardiac disease, use of immunosuppressant, and use of antibiotics for an exacerbation within the past 3 months.