Question

A child presented with fever, mild breathlessness and non-productive cough. She was treated with a course of antibiotics and improved over 4 days, but later deteriorated again with fever and more breathlessness. Chest X-ray showed hyperlucency. Pulmonary function test was suggestive of obstructive airway disease. The probable diagnosis would be?

• A. Bronchiolitis obliterans
• B. Alveolar proteinosis
• C. Post viral syndrome
• D. Asthma

Hint:

Post-infection relapse plus hyperlucency plus a fixed obstructive PFT equals obliterated small airways.

Answer 1

The Correct Option is A

Work this case as a sequence of clues that must all be satisfied by one diagnosis. First, the timeline: an acute lower respiratory infection that gets better for a few days and then relapses with greater breathlessness is the signature of permanent damage to the small airways occurring in the wake of the infection, not a fresh new infection. Second, the radiograph: hyperlucency means the affected lung is over-aerated and under-perfused because of air trapping behind narrowed or obliterated bronchioles, the classic picture associated with post-infectious small-airway scarring. Third, the lung-function data: an obstructive defect localizes the lesion to the conducting airways, and when that obstruction is fixed and follows an infection it points squarely at obliteration of the bronchioles. Now test the other choices against these three findings. Alveolar proteinosis fills the alveoli with lipoproteinaceous material, giving ground-glass opacification and a restrictive defect, the opposite of hyperlucency and obstruction. A simple post-viral syndrome resolves on its own and leaves no fixed obstruction. Asthma produces reversible bronchospasm, so its obstruction improves with bronchodilators and it does not generate persistent radiographic hyperlucency after one episode. Only one entity fits a post-infectious relapse plus hyperlucency plus fixed obstruction. $\text{Post-infection} + \text{hyperlucency} + \text{fixed obstruction} = \text{bronchiolitis obliterans}$.\[\boxed{\text{Bronchiolitis obliterans}}\]