Bronchiectasis

Definition

Bronchiectasis is a chronic respiratory condition characterized by permanent dilatation and destruction of the bronchial walls, resulting in impaired mucus clearance, recurrent infections, and airflow obstruction.

Epidemiology

• Prevalence varies globally, higher in low- and middle-income countries
• More common in adults, but can occur in children (post-infectious or congenital)
• Incidence increasing due to improved imaging and recognition
• Associated with cystic fibrosis in pediatric populations
• Recurrent respiratory infections are a common predisposing factor

Etiology

• Post-infectious: severe pneumonia, tuberculosis, pertussis, measles
• Genetic: cystic fibrosis, primary ciliary dyskinesia
• Immunodeficiency: IgG subclass deficiency, HIV
• Airway obstruction: tumors, foreign body, bronchial stenosis
• Allergic bronchopulmonary aspergillosis (ABPA)
• Other chronic inflammatory lung diseases

Pathophysiology

• Chronic infection and inflammation damage bronchial walls
• Loss of ciliary function impairs mucus clearance
• Airway dilatation leads to pooling of secretions
• Cycle of infection → inflammation → structural damage perpetuates disease
• Bronchial wall destruction causes airflow obstruction and ventilation-perfusion mismatch
• Exacerbations triggered by bacterial colonization
• Systemic inflammation may contribute to disease progression