- 90% of airway foreign bodies are radiolucent
- Need to rule out asthma / croup / bronchiolitis as cause of airway obstruction
Approach to the differential diagnosis of airway foreign body appearance acutely:
- Inspiratory and expiratory CXR are preferred but if they cannot be obtained then perform bilateral decubitus CXR
- Look for asymmetric aeration of the lungs on inspiration or air trapping on expiration / decubitus views – if a lobe or an entire lung does not deflate on expiration / decubitus views then suspect a radiolucent airway foreign body
- CXR that suggests asymmetric aeration of the lungs on inspiration or air trapping on expiration / decubitus views should result in bronchoscopy for foreign body removal