Foreign-body aspiration — formative SAQs

SAQ 1 — The choking toddler with a normal chest x-ray (20 marks, ~15 minutes)

A previously well 2-year-old is brought to the emergency department after a witnessed choking episode while eating peanuts. He coughed and went briefly blue, then settled. On arrival he is alert, pink and playing, with a mild intermittent cough, a subtle monophonic wheeze over the right chest and slightly reduced air entry on the right. His chest radiograph is reported as normal. ^[1]

Questions

1. Give the most likely diagnosis and state why the history is more important than the examination or the radiograph. (4 marks) ^[3]
2. Explain why the chest radiograph can be normal and what indirect signs you would look for. (5 marks) ^[7]
3. State your definitive management and justify it despite the normal radiograph. (5 marks) ^[8]
4. State the anatomical reason the object is likely to be on the right. (3 marks) ^[1]
5. State two pieces of prevention advice for the family. (3 marks) ^[6]

Model answer (must-hit)

1. The most likely diagnosis is an inhaled foreign body (aspirated peanut). The choking history is the strongest single predictor of aspiration and outperforms both examination and the chest radiograph, which each have imperfect sensitivity; a convincing choking story is itself an indication to act, whereas a well-looking child and a normal film do not exclude the diagnosis. ^{[3] [7]}
2. Most aspirated objects are organic and radiolucent, so the object itself is usually invisible. The indirect signs of the valve mechanism are unilateral air trapping and hyperinflation with mediastinal shift away from the affected side, or a lobar or segmental collapse; expiratory or lateral decubitus views can unmask air trapping missed on a single inspiratory film. A normal film never excludes aspiration. ^{[7] [1]}
3. Definitive management is rigid bronchoscopy under general anaesthesia, which is both diagnostic and therapeutic. It is justified because the choking history is itself an indication for bronchoscopy regardless of a normal radiograph, and the cost of a small number of negative bronchoscopies is far outweighed by the harm of a missed retained object progressing to recurrent pneumonia and bronchiectasis. ^{[8] [12]}
4. The right main bronchus is wider, shorter and more vertical than the left, giving a more direct path, so an aspirated object tends to follow gravity and airflow into the right side, which is reflected in the right-sided predominance of the large series. ^[1]
5. Avoid high-risk foods (whole nuts, hard sweets, whole grapes, hot dog pieces) in young children; supervise eating with the child seated and calm; and keep small toy parts and button batteries out of reach, in line with product-safety and choking-prevention guidance. ^[6]