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]

SAQ 2 — Recurrent same-lobe pneumonia (20 marks, ~15 minutes)

A 3-year-old has had three episodes of pneumonia in six months, each affecting the right lower lobe, with a persistent cough and a monophonic wheeze that has not responded to inhaled bronchodilators or steroids. There is no clear history of choking, but the parents recall an episode of coughing while eating some months ago. [12]

Questions

1. Give the most likely unifying diagnosis and the two clues that point to it. (4 marks) [1]
2. Explain why this has been mistaken for asthma and recurrent infection. (5 marks) [1]
3. State your investigation and management plan. (5 marks) [8]
4. State the complications of a long-retained foreign body. (4 marks) [12]
5. State one feature that would make you treat the situation as an immediate emergency. (2 marks) [1]

Model answer (must-hit)

1. The most likely unifying diagnosis is a retained bronchial foreign body. The two key clues are recurrent pneumonia always affecting the same lobe (a fixed local cause) and a monophonic wheeze that does not shift or respond to bronchodilators, together with the recalled coughing-while-eating episode consistent with an unwitnessed aspiration in the latent or delayed phase. [1] [12]
2. The fixed unilateral wheeze mimics asthma, so it was treated with bronchodilators and steroids, but a fixed monophonic wheeze that does not respond is not typical asthma. The recurrent infections mimic ordinary pneumonia, but infection that returns to the same lobe points to a fixed local obstruction rather than a diffuse or variable airway disease, and a retained foreign body is high on that differential. [1] [12]
3. Refer for rigid bronchoscopy under general anaesthesia, which is the definitive diagnostic and therapeutic step, to inspect the airway and remove the object; a chest radiograph and, if needed, CT can support the case but do not replace bronchoscopy. Treat any active post-obstructive pneumonia, and observe after removal for airway oedema and bleeding from granulation tissue. [8] [12]
4. A long-retained object causes chronic chemical bronchitis, granulation tissue, recurrent and persistent pneumonia, lobar or segmental collapse, and, if left, permanent localised bronchiectasis; removal itself may be complicated by oedema, bleeding and fragmentation. [12] [1]
5. Any feature of a critical or complete airway obstruction — an ineffective or silent cough, stridor, cyanosis or falling consciousness — would make this an immediate resuscitation emergency managed by the choking algorithm rather than a semi-elective bronchoscopy pathway. [1]