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At a glance

A symptom characterized by noisy breathing due to turbulent flow in the narrowed airways indicating partial obstruction of the upper airway, glottis, or trachea.



Genetic inheritance

Congenital stridor is a symptom rather than a syndrome, thus inheritance (if any) depends on the underlying cause.


Fixed or variable partial obstruction of the upper airway, glottis, or trachea may change the airflow pattern from laminar to turbulent, which results in noisy breathing. Stridor indicates substantial narrowing of the larynx and/or (extrathoracic) trachea. Hoarseness points to an abnormality of the glottis, while a muffled voice with a low-pitched stridor may be associated with supraglottic anomalies (eg, epiglottitis). Extrathoracic obstructions are usually associated with inspiratory stridor, whereas intrathoracic lesions usually result in expiratory stridor. Severe (sub-) glottic stenosis may result in biphasic (inspiratory and expiratory) stridor. The causes for congenital stridor are variable and can be divided into four categories: supralaryngeal, laryngeal, tracheal, and nonanatomical. They may include tracheoesophageal fistula, laryngomalacia, tracheomalacia, narrowing of the mainstem bronchus, ☞Pierre Robin sequence, dysfunction of cranial nerves IX to XII, curled epiglottis, congenital subglottic stenosis, laryngeal webs, laryngotracheal cleft, epipharyngeal fibroma, vascular rings, and bronchogenic cysts. In severe cases, gastroesophageal reflux may lead to stridor.


Patients usually present with stridor starting just after birth or shortly thereafter (first 4-6 weeks of life), feeding difficulties, frequent coughing, and/or recurrent aspirations. The diagnosis is based on the clinical finding of the characteristic breath sounds. The clinical circumstances may point to the etiology (association with position and feeding, persistent versus intermittent, abnormal phonation, foreign body exposure, presence of other congenital abnormalities). Laryngo-broncho-esophageal examination usually reveals the exact cause of the symptom. Check the percentiles for growth (weight and height) because increased work of breathing may lead to increased energy requirements and growth retardation.

Clinical aspects

Congenital stridor is a symptom rather than a syndrome, so the cause of the stridor must be sought. The most common cause of inspiratory stridor in the neonatal period is laryngomalacia, which accounts for approximately three-quarters of all cases. The stridor generally improves in the prone position with the head up. Symptoms typically begin at birth or within the first months of life, peak at 6 to 8 months, and most often resolve by 12 to 24 months of age. Laryngomalacia usually requires no therapy, but, rarely, in patients with severe obstruction (approximately 10% of patients), supraglottoplasty may be required. Noninvasive positive pressure ventilation (CPAP or BiPAP) has been used successfully in children with severe cases with respiratory distress. Unilateral vocal cord paralysis is probably the second most common cause of stridor in the neonatal period. It is either congenital or acquired (related to cardiothoracic surgery or birth trauma). Idiopathic ...

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