Bronchiectasis is an irreversible syndrome with typical symptoms of chronic productive cough and recurrent exacerbations and with characteristic findings on cross-sectional imaging of bronchial wall dilation and thickening.
- Overall annual incidence in U.S. adults estimated to be 29 cases per 100,000
- Widespread vaccination and improved recognition and treatment of childhood respiratory disease has led to decreased incidence among U.S. children.
- Incidence may be higher among indigenous or socioeconomically disadvantaged groups.
- Overall prevalence estimated to be 139 per 100,000 among U.S. adults
- Higher among women (180 per 100,000) than men (95 per 100,000)
- Prevalence increases with age: 562 per 100,000 among U.S. seniors aged >65 years
- Global estimates of prevalence in children ranges from 0.2 to 735 cases per 100,000.
- Large variability exists among different populations of children.
- Populations with higher prevalence include children with primary immune deficiencies, chronic aspiration, primary ciliary dyskinesia, airway malformations, and children in low-income countries.
Etiology and Pathophysiology
- Bronchiectasis is sometimes identified as an isolated pulmonary diagnosis.
- Often arises as a complication of other inherited or acquired disease states
- Vicious cycle hypothesis:
- An initial pulmonary insult causes airway inflammation, dysfunction, and structural disease.
- Dysfunctional airways are further impaired in their ability to clear infections.
- A pattern of lung damage/inflammation and progressive airway dysfunction is established, leading to clinical decline.
- Neutrophil extracellular traps (NETs) and neutrophil elastase are thought to play an important role.
- Higher levels/activity of these markers correlate with disease activity and may serve as potential therapeutic targets (1).
Conditions/exposures which cause impaired host defenses, altered tracheobronchial anatomy, airway inflammation, and airway clearance all predispose to development of bronchiectasis.
- Routine immunization against respiratory infections (pertussis, measles, Haemophilus influenzae type B (HIB), influenza, and Streptococcus pneumonia)
- Early recognition and treatment of conditions which can lead to bronchiectasis
- Genetic counseling for patients with inheritable conditions which predispose to bronchiectasis who wish to conceive
- Smoking cessation
Commonly Associated Conditions
- Prevalence of conditions associated with bronchiectasis based on U.S. data published in 2017:
- Pneumonia (68%)
- GERD (47%)
- Asthma (29%)
- Chronic obstructive pulmonary disease (COPD) (20%)
- Any rheumatologic disease (8%)
- Immunodeficiency (5%)
- History of tuberculosis (TB) (4%)
- Inflammatory bowel disease (3%)
- Primary ciliary dyskinesia (3%)
- Other conditions which have been associated with bronchiectasis include:
- Allergic bronchopulmonary aspergillosis (ABPA)
- Chronic rhinosinusitis
- Congenital abnormalities of the airways (e.g., tracheobronchomalacia)
- α1-Antitrypsin deficiency
There's more to see -- the rest of this topic is available only to subscribers.