DESCRIPTION

Dynamic collapse of supraglottic laryngeal structures during inspiration

EPIDEMIOLOGY

• Most common cause of stridor in infants (65–75%)
• Male-to-female ratio is 2:1.
• Associated with prematurity and gastroesophageal reflux (GER) (>65%)

ETIOLOGY

• Exact cause unknown
• Redundant supraglottic tissue
• Decreased neuromuscular tone and altered sensorimotor integrative function of the larynx
• Laryngeal inflammation

PATHOPHYSIOLOGY

• Most commonly presents within the first few weeks of life, worsens in severity over the first 6 months
• Most cases gradually resolve by 18 to 24 months.
• 10% require surgical intervention.
• Less common late-onset type presents later in childhood/adolescence; symptoms associated with feeding, sleep, or exercise
• Due to redundant supraglottic tissue collapse
• Decreased airway radius → increased airway resistance (1/r⁴ Poiseuille law)
• Increased turbulent airflow/velocity further contributes to obstruction (Bernoulli principle).