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Stridor is a harsh noise produced by turbulent airflow through a partially obstructed airway. It may be inspiratory, expiratory, or both (biphasic). The term stertor is used to describe airway noise originating in the nose, nasopharynx, and oropharynx; therefore, stridor is generally of laryngeal or tracheal origin. As a general rule, inspiratory stridor originates from the supraglottis and glottis, expiratory stridor from the trachea, and biphasic stridor from the subglottis. There is a wide variety of causes of airway obstruction in children (Table 33–1). This chapter describes the more common laryngeal abnormalities that can cause stridor.

Table 33–1. Causes of Airway Obstruction in Infants and Children.

Essentials of Diagnosis

  • Intermittent, positional inspiratory stridor (usually mild).
  • Gradual worsening of stridor followed by spontaneous resolution.
  • Supraglottic collapse on inspiration.

General Considerations

Laryngomalacia is the most common cause of stridor in infants, and is also the most common congenital laryngeal abnormality, accounting for approximately 60% of cases. Stridor occurs as a result of prolapse of the supraglottic structures into the laryngeal inlet on inspiration. The epiglottis is classically described as being omega shaped and folded in upon itself so that the lateral margins lie close to each other (Figure 33–1). The aryepiglottic folds are tall, foreshortened, and thin, and the arytenoids are large with redundant mucosa. Mucosal edema resulting from repeated vibratory trauma to the supraglottis exacerbates the symptoms.

Figure 33–1.

Appearance of the infantile larynx in laryngomalacia.

Although most cases of laryngomalacia have a benign course without any long-term sequelae, the most severe cases, in which significant desaturation occurs, can result in significant morbidity, such as pulmonary hypertension and cor pulmonale.

The incidence of synchronous airway lesions associated with laryngomalacia has been reported in 12–45% of cases, although less than 5% of these cases require intervention.

Clinical Findings

Symptoms and Signs

Infants with laryngomalacia usually have no sign of respiratory abnormality at birth. Inspiratory stridor typically develops after a few days or weeks and is initially mild, but over ...

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