Bronchiectasis in Children
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Direct answer
Any child with a wet cough lasting beyond four weeks has bronchiectasis until imaging says otherwise: permanent, abnormal dilatation of the bronchi, defined today by high-resolution computed tomography rather than the obsolete bronchogram. In Indian practice the commonest driver is post-infectious injury — tuberculosis, measles, pertussis and adenovirus — whereas cystic fibrosis dominates Western lists; other causes include primary ciliary dyskinesia, immunodeficiency and inhaled foreign bodies. The CT hallmarks are a broncho-arterial ratio above about 0.8 in children (above 1.0 in adults), lack of bronchial tapering, wall thickening and the signet-ring sign. Management is airway clearance with physiotherapy, prolonged antibiotics for exacerbations (typically 14 days), thrice-weekly azithromycin prophylaxis in recurrent cases, and immunisation, with the cause hunted in every child.
What you must remember
- Definition threshold: chronic wet cough of more than four weeks in a child justifies investigation, and bronchiectasis is the diagnosis the CT confirms; the broncho-arterial ratio above roughly 0.8 is the paediatric cut-off.
- Indian cause hierarchy: post-infectious scarring (tuberculosis above all, then measles, pertussis, adenovirus) is commonest in India, while cystic fibrosis leads in high-income settings — the same disease with reversed geographies.
- Kartagener syndrome: the triad of situs inversus, sinusitis and bronchiectasis, pointing to primary ciliary dyskinesia; ask about neonatal respiratory distress, recurrent otitis and heterotaxy in siblings.
- Cystic fibrosis screen: in any child with bronchiectasis, recurrent chest disease, failure to thrive or steatorrhoea, sweat chloride testing remains the gateway test; faecal elastase screens pancreatic sufficiency.
- Signet-ring sign: a dilated bronchus visibly larger than its accompanying pulmonary artery branch on CT — the single most quoted radiological sign in this topic.
- Exacerbation rule: antibiotics for 14 days, guided by sputum culture where available, targeting Haemophilus influenzae, pneumococcus, Staphylococcus aureus and, in Indian series, Pseudomonas aeruginosa.
- Long-term therapy: airway clearance daily, influenza and pneumococcal vaccination, nutrition, and thrice-weekly azithromycin (around 5 mg/kg per dose) for children with frequent exacerbations.
A step-by-step diagnostic approach
Begin with a five-year-old with a daily wet cough for a year, two pneumonias and mild finger clubbing. Step one confirms the chronicity and excludes the reversible mimics: a retained inhaled foreign body (always ask about a choking episode), active tuberculosis (sputum or gastric aspirate for bacilli and radiography) and treatable asthma with productive cough. Step two sends the basic aetiological screen — full blood count with immunoglobulins and subsets, sweat chloride, and, if the story suggests it, ciliary studies from a nasal brush biopsy after a infection-free interval. Step three is the high-resolution CT, performed electively when the child is at baseline rather than mid-exacerbation, because transient post-infectious changes can overcall dilatation; the report should state the ratio, the distribution (lower-lobe predominance suggests aspiration or post-infectious disease; upper-lobe, cystic fibrosis or tuberculosis) and the presence of tree-in-bud mucous plugging. Step four builds the management plan around the cause: physiotherapy and inhaled therapies for all, enzyme and calorie support for cystic fibrosis, immunoglobulin replacement where deficient, and ear-nose-throat coordination for the ciliary dyskinesia child with sinus disease.
Step five is the long game — monitoring growth, lung function and exacerbation frequency, because childhood bronchiectasis, unlike the adult form, can stabilise and even partially reverse with disciplined care.
How the exam frames it
The recurring stem pairs a chronic wet cough with a discriminating clue: situs inversus (Kartagener), a choking episode at age two (foreign body), steatorrhoea and failure to thrive (cystic fibrosis), or a treated tuberculosis history in an Indian child (post-tubercular bronchiectasis). The expected diagnostic answer is high-resolution CT, and the expected mistake is choosing bronchoscopy or bronchography — the latter is the historical answer, and examiners still deploy it as a trap. The second scored area is the ratio itself (0.8 in children versus 1.0 in adults) and the realisation that paediatric airways are normally relatively larger, which is why the adult cut-off overcalls children. In vivas, the Indian post-infectious hierarchy is expected knowledge; answering with cystic fibrosis first in an Indian setting reads as textbook recital rather than clinical sense.
Frequently asked questions
What CT criteria diagnose bronchiectasis in a child?
A broncho-arterial ratio above approximately 0.8 with lack of bronchial tapering, airway wall thickening and signet-ring appearance on high-resolution computed tomography.
What is the commonest cause of childhood bronchiectasis in India?
Post-infectious lung injury, chiefly tuberculosis followed by measles, pertussis and adenovirus, in contrast to cystic fibrosis in Western populations.
Which syndrome combines situs inversus with bronchiectasis?
Kartagener syndrome, the classic phenotype of primary ciliary dyskinesia, with sinusitis completing the triad and infertility appearing after puberty.
How long should antibiotics run for an exacerbation?
Typically 14 days, chosen on culture where possible, targeting Haemophilus influenzae, pneumococcus, staphylococcus and pseudomonas in chronically damaged airways.
What is the role of long-term azithromycin?
Thrice-weekly prophylactic azithromycin (about 5 mg/kg per dose) reduces exacerbations in children with recurrent attacks, alongside daily airway clearance and full immunisation.