Infant Stridor Etiology Cheatsheet
Key Concept: Biphasic stridor + no improvement prone = subglottic hemangioma or vascular ring. Laryngomalacia = inspiratory only, worsens supine, improves prone. Choanal atresia = nasal obstruction, cyclic cyanosis, improves crying. Tracheomalacia = expiratory predominant, barky cough, associated with EA/TEF repair.
| Diagnosis |
Key Features |
| Subglottic Hemangioma |
- Subglottic location → biphasic (inspiratory + expiratory) stridor
- Exhalation component prominent — fixed obstruction below glottis
- No improvement in prone position (unlike laryngomalacia)
- Large facial hemangioma → PHACE syndrome workup (MRI + echo)
- Beard-distribution hemangioma → laryngoscopy for airway involvement
- Oral propranolol is first-line treatment
- Presents at 1–3 months as proliferative phase begins
|
| Laryngomalacia |
- Most common cause of stridor in infants
- Inspiratory-only stridor (no expiratory component)
- Worsens supine and with feeding
- Improves prone (gravity pulls arytenoids away from airway)
- Floppy arytenoids/epiglottis collapse inward on inspiration
- Flexible laryngoscopy: omega-shaped epiglottis
- Resolves spontaneously by 12–18 months in most cases
- Supraglottoplasty if severe GERD or failure to thrive
|
| Choanal Atresia |
- Bony or membranous obstruction of posterior nasal choanae
- Cyclic cyanosis in neonates — nasal obligate breathers
- Cyanosis improves with crying (opens mouth)
- Cannot pass suction catheter through nose
- Does NOT present as classic stridor
- CT scan is diagnostic
- Emergency: oral airway or intubation; definitive = surgical repair
|
| Tracheomalacia |
- Weakened tracheal cartilage → dynamic collapse during exhalation
- Expiratory stridor/wheeze predominant
- Barky cough; worsens with crying and upper respiratory infections
- Associated with esophageal atresia/TEF repair
- Improves with neck extension (anterior tracheal wall tension)
- Dynamic airway fluoroscopy or flexible bronchoscopy diagnostic
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