Laryngomalacia

Updated: Apr 21, 2017
  • Author: Stephanie Lovinsky-Desir, MD, MS; Chief Editor: Denise Serebrisky, MD  more...
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Overview

Background

Laryngomalacia, shown in the image below, is a congenital abnormality of the laryngeal cartilage. It is a dynamic lesion resulting in collapse of the supraglottic structures during inspiration, leading to airway obstruction. It is thought to represent a delay of maturation of the supporting structures of the larynx. Laryngomalacia is the most common cause of congenital stridor and is the most common congenital lesion of the larynx.

Laryngomalacia: The epiglottis is small and curled Laryngomalacia: The epiglottis is small and curled on itself (omega-shaped). Approximation of the posterior edges of the epiglottis contributes to the inspiratory obstruction. (From B Benjamin, Atlas of Paediatric Endoscopy, Oxford University Press, NY, 1981, with permission.)
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Pathophysiology

Laryngomalacia may affect the epiglottis, the arytenoid cartilages, or both. When the epiglottis is involved, it is often elongated, and the walls fold in on themselves. The epiglottis in cross section resembles an omega, and the lesion has been referred to as an omega-shaped epiglottis. If the arytenoid cartilages are involved, they appear enlarged. In either case, the cartilage is floppy and is noted to prolapse over the larynx during inspiration. This inspiratory obstruction causes an inspiratory noise, which may be high-pitched sounds frequently heard in other causes of stridor, coarse sounds resembling nasal congestion, and low-pitched stertorous noises. More severe compromise may be associated with a lower ratio of the aryepiglottic fold length to the glottic length.

A classification system has been proposed. In type 1 laryngomalacia, the aryepiglottic folds are tightened or foreshortened. Type 2 is marked by redundant soft tissue in any area of the supraglottic region. Type 3 is associated with other disorders, such as neuromuscular disease and gastroesophageal reflux.

Laryngomalacia is the most common cause of chronic inspiratory noise in infants, no matter which type of noise is heard. Infants with laryngomalacia have a higher incidence of gastroesophageal reflux, presumably a result of the more negative intrathoracic pressures necessary to overcome the inspiratory obstruction. Conversely, children with significant reflux may have pathologic changes similar to laryngomalacia, especially enlargement and swelling of the arytenoid cartilages. Some of the swelling of the arytenoid cartilages and of the epiglottis may be secondary to reflux.

Occasional inflammatory changes are observed in the larynx, which is referred to as reflux laryngitis. When the epiglottis is involved, gravity makes the noise more prominent when the baby is supine.

The exaggerated inspiratory effort increases blood return to the pulmonary vascular bed. This could account for the increased likelihood of pulmonary artery hypertension in infants with hypoxemia.

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Epidemiology

Frequency

United States

Frequency is unknown. Often, the diagnosis is presumed.

Mortality/Morbidity

Rarely, the lesion may cause enough hypoxemia or hypoventilation to interfere with normal growth and development. In severe cases, when laryngomalacia may be associated with gastroesophageal reflux, feeding problems such as choking or gagging may occur.

Race

No known race predilection has been reported.

Sex

Although previous reports in predominately white populations have reported a male predominance (58-76% of cases), a more recent study of a more ethnically diverse population demonstrated no significant difference between males and females. [1]

Age

Although this is a congenital lesion, airway sounds typically begin at age 4-6 weeks. Until that age, inspiratory flow rates may not be high enough to generate the sounds. Symptoms typically peak at age 6-8 months and remit by age 2 years.

Late-onset laryngomalacia may be a distinct entity, which can present after age 2 years.

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