Learning Radiology xray montage
 
 
 
 
 

The Lateral Neck
Croup

  • Soft tissue measurements on the lateral neck image
    • At C3: <3 mm (less than 1/3 AP diameter)
    • At C6: < the AP width of C6 vertebral body
  • Retropharyngeal Space
    • Contains lymphatics that drain
      • Nasopharynx
      • Adenoids
      • Posterior nasal sinuses
    • These chains atrophy after age 4
  • Retropharyngeal abscess
    • Almost all occur before age 6
    • 50% between 6-12 months
    • Most common pathogens are
      • Staph aureus
      • Group A Beta hemolytic Strep
      • Hemophilus
    • Clinically
      • Prodromal nasopharyngitis
      • Severe throat pain with drooling
      • Dysphagia
      • Hyperextension of the head
      • “Hot potato” muffled voice
    • In adults, usually 2° trauma to oropharynx
      • Iatrogenic
      • Perforated FB
  • Retropharyngeal perforation
    • Causes
      • Trauma to esophagus or trachea
      • Penetrating injuries from weapons
      • Perforation from within
        • Chicken bone
        • Mediastinal emphysema tracking into neck
      • Retropharyngeal abscess 2° gas-forming organism
  • Imaging findings of retropharyngeal perforation
    • Streaks of air in soft tissues of neck
    • Anterior displacement of pharynx
    • Associated pneumothorax possible
    • Cervical or mediastinal air seen in 60% of cases of ruptured esophagus
  • Upper airway infections-The Big Two
    • Croup
    • Epiglottitis
  • Croup
    • Laryngeotracheobronchitis
    • Usually viral
    • May be difficult to distinguish from early retropharyngeal abscess
    • Occurs at age 6 months to 2 years
      • Younger than epiglottitis
    • The three major findings of croup
      • Distension of the hypopharynx
      • Distension of the laryngeal ventricle
      • Haziness or narrowing of subglottic space
  • Epiglottitis
    • Most commonly H. flu type B
    • Peak incidence now closer to 6-7 years
      • Croup occurs from 6 months to 2 years
    • Lateral radiograph -- erect position only
      • Supine position may close off airway
    • Imaging findings
      • Epiglottis is enlarged
      • Appears thumb-like
      • Aryepiglottic folds are thickened
      • Pre-epiglottic space (vallecula) is smaller than normal
        • In many cases, it’s obliterated
  • Impacted esophageal foreign bodies
    • Food or true foreign bodies
      • Chicken bones (opaque), fish bones (non-opaque)
      • Coins, toy trucks
    • Most often they impact just below cricopharyngeous (70%)
      • Another 20% impact at the level of the aortic arch
      • Another 10% at EG junction
      • Once past the esophagus, most foreign bodies will pass through the GI tract
    • Clinical findings of an impacted esophageal foreign body
      • Dysphagia and odynophagia most commonly
      • Even if FB passes, many complain of pain referable to cervical esophagus
    • Always check for lead lines in children
      • Pica
    • Chicken bones are usually opaque
      • Fish bones contain less calcium and usually are not
    • Plain films usually do not demonstrate the FB but are still obtained first
      • If negative, then either contrast esophagram or CT if high index of suspicion
    • Treatment
      • Removal is most often performed using endoscopy
      • Temporization and surgery are other options
      • An ingested button battery lodged in esophagus must be removed immediately
    • Complications of an impacted foreign body
      • Perforation
        • Longer the FB remains impacted (>24hrs), higher incidence of perforation
      • Stricture
      • Diverticulum formation

Croup. Soft tissue lateral neck demonstrates a dilated hypopharynx (red arrow),
dilatation of the laryngeal ventricle (white arrow) and narrowing of the
subglottic trachea (blue arrow).

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