DDX of acute upper airway obstruction

Approach to acute upper airway obstruction:

  • Infection
    • Croup is a glottic + subglottic process with a steeple sign
    • Exudative tracheitis is a glottic + subglottic process with an indistinct trachea containing plaques
    • Epiglottitis is a supraglottic process with an enlarged epiglottis + aryepiglottic folds
    • Retropharyngeal abscess is diagnosed when there is soft tissue thickening of > 1 cervical vertebral body
  • Foreign body
    • Airway foreign bodies cause air trapping which is best seen on expiratory or decubitus CXR
    • Esophageal foreign bodies can cause surrounding edema leading to tracheal narrowing
  • Beware of false positives due to lateral airway images obtained in expiration / flexion