Bronchiectasis in children — short-answer question

Part A — Definition, continuum and mechanism (10 marks)

a) Define bronchiectasis and explain the chronic suppurative lung disease continuum (4 marks)

Bronchiectasis is permanent, abnormal dilatation of the bronchi caused by chronic infection and inflammation, confirmed on chest high-resolution CT when a bronchus is wider than its adjacent artery. Its clinical hallmark, present long before any scan, is a chronic wet or productive cough lasting more than four weeks. Chronic suppurative lung disease describes the same child with the same wet cough and lower-airway neutrophilic infection whose HRCT does not yet meet radiological criteria for bronchiectasis. They are the same disease at different stages, so this boy's persistent wet cough should be treated as suppurative lung disease and the reversible front end of bronchiectasis. ^{[1] [2]}

b) Explain why his wet cough matters and outline the underlying mechanism (4 marks)

A wet cough that recurs the moment antibiotics stop signals an airway that cannot clear itself, not a run of viruses. The mechanism is a self-perpetuating vicious cycle: an initial insult impairs mucociliary clearance, secretions stagnate, bacteria colonise the pooled mucus, and chronic neutrophilic inflammation releases enzymes that destroy the airway wall, so the bronchus dilates and drains even worse. This locks in further infection and, if uninterrupted, ends in permanent dilatation. ^{[1] [2]}

c) State why early recognition is especially important in this child (2 marks)

In young children, early bronchiectasis on HRCT can regress with intensive treatment, so acting at the wet-cough stage can save the airway. This boy is also Aboriginal, and Aboriginal and Torres Strait Islander children carry among the highest rates of bronchiectasis in the world, much of it preventable, making early recognition both a clinical and an equity imperative. ^{[2] [1]}