Airway foreign bodies in children are potentially fatal, which is why immediate recognition is important. Unfortunately, delayed diagnosis is common.
Children under the age of four years are at increased risk of foreign body (FB) aspiration, with a slight male predominance 1.
Most children (~70%) are witnessed to have had a choking event at the time of aspiration. Children may otherwise present with cough, dyspnea, or irritability 2,6.
Most (70-90%) foreign bodies are organic, most commonly seeds and nuts. Inorganic foreign bodies vary dramatically and can include teeth, coins, pins, pens/crayons, etc.
Aspirated foreign bodies have a predilection for the right tracheobronchial tree, given the wider and steeper structure of the right main bronchus 6.
The hallmark of an aspirated foreign body is a lung volume that does not change during the respiratory cycle 6. Medical imaging departments will have a dedicated suspected foreign body inhalation series.
- the patient should be radiographed on expiration: this will exaggerate the differences between the lungs
- in infants and toddlers, a parent can be asked to push inward and upward on the child's upper abdomen for attaining expiration
- the normal lung should appear smaller and denser than the affected lung
- due to the check valve mechanism, where air enters the bronchus around the foreign body but cannot exit, the affected lung will usually appear overinflated and hyperlucent, with concomitant rib flaring and a depressed ipsilateral hemidiaphragm
- interrupted bronchus sign
- the chest x-ray will be normal in ~35% (range 30-40%) of patients 1-2
- the majority of foreign bodies are radiolucent 6
- unilateral emphysema or atelectasis are the most common findings; only uncommonly will a radiopaque foreign body be demonstrated 1-2
In case there is a high suspicion of foreign body aspiration by an infant or toddler, but the chest x-ray is inconclusive, fluoroscopy may be attempted. The child is imaged in the lateral decubitus position, lying on the presumed affected side. The occluded lung is immobile on inspiration-respiration.
Can be useful in the assessment of a missed or retained foreign body after initial bronchoscopy 3.
Treatment and prognosis
Bronchoscopy is considered the gold standard in the diagnosis of tracheobronchial tree foreign bodies 3, with the added benefit of being able to potentially retrieve the foreign body.
- pneumonia or atelectasis
- broncho-esophageal fistula
- esophageal foreign body
- flat foreign bodies (e.g. coins) tend to lie in the coronal plane in the esophagus 4
- lung hyperinflation 6
- 1. Passàli D, Lauriello M, Bellussi L et-al. Foreign body inhalation in children: an update. Acta Otorhinolaryngol Ital. 2010;30 (1): 27-32. Free text at pubmed - Pubmed citation
- 2. Chik KK, Miu TY, Chan CW. Foreign body aspiration in Hong Kong Chinese children. Hong Kong Med J. 2009;15 (1): 6-11. Pubmed citation
- 3. Shin SM, Kim WS, Cheon JE et-al. CT in children with suspected residual foreign body in airway after bronchoscopy. AJR Am J Roentgenol. 2009;192 (6): 1744-51. doi:10.2214/AJR.07.3770 - Pubmed citation
- 4. Rotta AT, Wiryawan B. Respiratory emergencies in children. Respir Care. 2003;48 (3): 248-58. Pubmed citation
- 5. Textbook of Pediatric Emergency Medicine. Lippincott Williams & Wilkins. ISBN:1605471593. Read it at Google Books - Find it at Amazon
- 6. Martin L. Gunn. Pearls and Pitfalls in Emergency Radiology. ISBN: 9781139619899