Airway Foreign Body

  • Etiology: foreign body below vocal cords in larynx + trachea (15%) / left mainstem bronchi (23%) / right mainstem bronchi (60%), causes ball valve effect, most common is peanut and peanut is bad because protein incites vicious foreign body reaction
  • Note: goal of imaging at early presentation is to rule out asthma / croup / bronchiolitis and decide who needs bronchoscopy to avoid delayed diagnosis
  • Imaging at early presentation: 90% of foreign bodies are radiolucent, 33% of inspiratory CXR are normal, classically see hyperinflation / mediastinal shift, lack of change in lung volume / asymmetrical air trapping – affected lung does not deflate in expiration or when placed down on decubitus, heart swings towards affected side on inspiration (rocker heart)
  • Imaging at late presentation: atelectasis, pneumonia, abscess
  • Secondary signs of upper airway foreign body: symmetric lung lucency, enlarged hypopharynx, retropharyngeal soft tissue swelling
  • Secondary signs of lower airway foreign body: asymmetric lung lucency, atelectasis, pleural effusion, pneumothorax
  • DDX: symptoms overlap with asthma, croup, bronchiolitis
  • Clinical: 50-75% present within 24 hours, < 50% have classic triad of wheez / cough / decreased breath sounds

Cases of Airway Foreign Body

CXR of airway foreign body
CXR taken in inspiration (above) shows symmetrical aeration of the lungs. CXR taken in expiration (below) shows air trapping in the right lung.
Radiograph of airway foreign body
Lateral radiograph of the airway shows a subglottic soft tissue mass. Endoscopy showed a sunflower seed surrounded by granulation tissue.