Most common cause of acute stridor: Croup

Most common cause of chronic stridor: Laryngomalacia

Inspiratory stridor - obstruction of extrathoracic region

Expiratory stridor - obstruction of inthrathoracic region

Causes

• Inhaled FB
• Adenoid hypertrophy
• Tonsil hypertrophy (peritonsillar abscess)
• Macroglossia - angiooedema (anaphylaxis), amyloidosis, ludwings angina, congenital
• Epiglottitis
• Laryngomalacia (congenital) - due to deficits in the maturation of laryngeal structures
  • Worse when child is in supine position, when agitated/crying
  • characteristic omega sign seen in the epiglottis - on inspiration
• Laryngeal web - fibrous layer of tissue between vocal cords
• vocal cord paralysis