What are the causes of bronchiectasis in children?

Causes of Bronchiectasis in Children

Bronchiectasis in children has identifiable causes in 52-86% of cases, with post-infectious etiologies, cystic fibrosis, primary ciliary dyskinesia, and immunodeficiency being the most common, though the specific distribution varies by geographic region and healthcare setting. 1

Most Common Etiologies

Post-Infectious Causes

• Previous severe pneumonia or bronchiolitis represents one of the leading causes, accounting for approximately 9.7-32.6% of cases depending on the population studied 2, 3
• Bronchiolitis obliterans following severe viral infection (particularly adenovirus, influenza, or RSV) was the single most common cause in one large pediatric series at 32.6% 2
• Post-tuberculosis bronchiectasis remains important in high-prevalence regions 1

Genetic and Congenital Disorders

• Cystic fibrosis is one of the most common identifiable causes in developed countries, occurring in 1 per 2,000-3,000 live births, and should be excluded with sweat testing in all children with bronchiectasis 4, 5
• Primary ciliary dyskinesia accounts for 4.3-9.7% of pediatric cases and causes impaired mucociliary clearance leading to recurrent sinopulmonary infections 2, 3
• Congenital structural abnormalities including Williams-Campbell syndrome (cartilage deficiency), Mounier-Kuhn syndrome (tracheobronchomegaly), and lung sequestration are rare but important causes 1, 4

Immunodeficiency

• Antibody deficiency syndromes (hypogammaglobulinemia, particularly IgG and IgG subclasses) account for 8.6-9.7% of pediatric cases 1, 2, 3
• Immunological evaluation provides a diagnosis in approximately 42% of children when systematically investigated 1
• HIV infection can cause bronchiectasis and should be tested in high-prevalence settings 1, 4

Allergic and Inflammatory Conditions

• Allergic bronchopulmonary aspergillosis (ABPA) causes central cystic bronchiectasis and occurs in 1-8% of bronchiectasis patients, characterized by elevated total IgE >500 IU/mL and positive Aspergillus-specific IgE 1, 5
• Interstitial lung disease was identified as the underlying cause in 17.3% of one pediatric cohort 2

Aspiration and Airway Obstruction

• Foreign body aspiration or chronic aspiration from swallowing dysfunction can cause localized bronchiectasis 4, 6
• Bronchial obstruction from tumors, broncholithiasis, or compression by lymph nodes leads to post-obstructive bronchiectasis 4

Less Common Causes

• Rheumatoid arthritis and other connective tissue disorders (though more common in adults, accounting for 2-5% of cases) 1, 4
• Inflammatory bowel disease can predispose to bronchiectasis development 4, 7
• Alpha-1-antitrypsin deficiency is found in <1% of cases 1, 4

Recommended Diagnostic Evaluation

The 2021 ERS guidelines recommend a minimum panel of investigations for all children with bronchiectasis: 1

1. Chest CT scan (high-resolution) to confirm diagnosis with >90% sensitivity and specificity 4, 5
2. Sweat test to exclude cystic fibrosis 1
3. Lung function tests (spirometry in children capable of performing it) 1
4. Full blood count 1
5. Immunological tests: total IgG, IgA, IgM, IgE, and specific antibodies to vaccine antigens 1
6. Lower airway bacteriology (sputum culture or bronchoscopy if non-expectorating) 1

In tuberculosis or HIV endemic regions, testing for these infections should be included in the minimum panel. 1

Additional Targeted Testing Based on Clinical Presentation

Consider these investigations when clinical features suggest specific etiologies: 1

• Primary ciliary dyskinesia testing (nasal nitric oxide, high-speed video microscopy analysis, transmission electron microscopy) if there is chronic rhinosinusitis, neonatal respiratory distress, situs abnormalities, or consanguinity 1
• Diagnostic bronchoscopy with bronchoalveolar lavage provides useful information in 12-41% of cases, particularly for identifying non-tuberculous mycobacteria or when patients cannot expectorate 1
• In-depth immunological assessment in consultation with pediatric immunology if initial screening suggests deficiency 1
• Aspiration studies (modified barium swallow, pH probe) if there is history of choking, feeding difficulties, or neurological impairment 1
• ABPA testing (total IgE, Aspergillus-specific IgE, skin prick testing) if there is central bronchiectasis distribution on CT or coexisting asthma 1, 5

Critical Clinical Considerations

The etiology remains idiopathic in 14-48% of pediatric cases despite comprehensive investigation, though this percentage is decreasing with improved diagnostic techniques. 2, 3

Early diagnosis is particularly crucial in children because mild radiographic bronchiectasis may be reversible if treated optimally early, whereas delayed diagnosis leads to irreversible lung damage and worse long-term outcomes. 1, 8

Mean time from symptom onset to diagnosis averages 2.7 years in some series, representing a critical window where intervention could prevent progression. 3

Geographic and socioeconomic factors significantly influence the distribution of causes—post-infectious etiologies predominate in developing countries, while genetic causes like cystic fibrosis are more commonly identified in developed nations with better access to specialized testing. 8, 2, 3