Stridor

1. See Also
   1. Wheezing
   2. Stertor
2. Pathophysiology
   1. Turbulent air flow in a partially obstructed upper airway results in a high pitched sound
   2. Location of obstruction determines inspiratory or biphasic timing
      1. Obstruction above the glottis results in Inspiratory Stridor
      2. Obstruction at or immediately below the glottis results in both inspiratory and expiratory Stridor (Biphasic Stridor)
3. Epidemiology
   1. Most common in younger children
      1. A child's small airways are impacted most significantly by even relatively small partial obstructions
      2. Airway diameter reduction of 25% results in a cross-sectional airway reduction of 50%
4. Causes: Stridor under age 6 months
   1. Laryngomalacia (60%)
   2. Croup
   3. Vocal Cord Paralysis
   4. Subglottic Stenosis
   5. Airway Hemangioma
   6. Vascular Rings or slings
5. Causes: Congenital
   1. Choanal Atresia
   2. Maxillofacial dysplasia
   3. Vascular anomalies (e.g. Vascular Ring)
   4. Laryngeal or tracheal abnormalities
   5. Laryngomalacia
   6. Tracheomalacia
   7. Bronchomalacia
6. Causes: Inflammatory or Infectious
   1. Laryngotracheal Bronchitis (Croup)
   2. Epiglottitis
   3. Bacterial Tracheitis
   4. Tonsillitis
   5. Diphtheria
   6. Oropharyngeal deep space infection
      1. Peritonsillar Abscess
      2. Retropharyngeal Abscess
7. Causes: Neoplasm
   1. Airway Papilloma
   2. Airway Hemangioma
8. Causes: Neurogenic
   1. Vocal Cord Paralysis
   2. Aspiration
9. Causes: Trauma
   1. Foreign Body Aspiration
   2. Facial Fracture
   3. Mandibular Fracture
   4. Laryngeal Fracture
   5. Subglottic Stenosis
10. Causes: Allergy
    1. Spasmodic Croup
    2. Angioneurotic edema