Congenital Anomalies of the Larynx, Trachea, and Bronchi

Keywords

• laryngomalacia

• infant

• stridor

Clinical Manifestations

Laryngomalacia accounts for 45% to 75% of congenital laryngeal anomalies in children with stridor. Stridor is inspiratory, low-pitched, and exacerbated by any exertion: crying, agitation, or feeding. The stridor is caused, in part, by decreased laryngeal tone leading to supraglottic collapse during inspiration. Symptoms usually appear within the 1st 2 wk and increase in severity for up to 6 mo, although gradual improvement can begin at any time. Gastroesophageal reflux disease, laryngopharyngeal reflux disease, and neurologic disease influence the severity of the disease and thereby the clinical course.

Diagnosis

The diagnosis is made primarily based on symptoms. The diagnosis is confirmed by outpatient flexible laryngoscopy ( Fig. 413.1 ). When the work of breathing is moderate to severe, airway films and chest radiographs are indicated. Laryngomalacia can contribute to feeding difficulties and dysphagia in some children because of decreased laryngeal sensation and poor suck-swallow-breath coordination. When the inspiratory stridor sounds wet or is associated with a cough or when there is a history of repeat upper respiratory illness or pneumonia, dysphagia should be considered. When dysphagia is suspected, a contrast swallow study and/or a fiberoptic endoscopic evaluation of swallowing (FEES) may be considered. Because 15–60% of infants with laryngomalacia have synchronous airway anomalies, complete bronchoscopy is undertaken for patients with moderate to severe obstruction.

Treatment

Expectant observation is suitable for most infants because most symptoms resolve spontaneously as the child and airway grow. Laryngopharyngeal reflux is managed aggressively with antireflux medications, such as histamine H2 receptor antagonists (H2RAs) or proton pump inhibitors (PPIs). Risk:benefit ratio should be assessed in each patient because these medications, particularly PPIs, have been associated with iron-deficiency anemia, increased incidence of pneumonia, gastroenteritis, and Clostridium difficile infections, among others. In 15–20% of patients, symptoms are severe enough to cause progressive respiratory distress, cyanosis, failure to thrive, or cor pulmonale. In these patients, surgical intervention via supraglottoplasty is considered. Supraglottoplasty is 90% successful in relieving upper airway obstruction caused by laryngomalacia. Some comorbidities, such as cardiac disease, neurologic disease, pulmonary disorders, or craniofacial anomalies may be poor prognostic indicators that would suggest earlier intervention.

Keywords

• subglottic stenosis

• recurrent bronchiolitis

• recurrent croup

Clinical Manifestations

Congenital subglottic stenosis is the second most common cause of stridor. The subglottis is the narrowest part of the upper airway in a child and is located in the space extending from the undersurface of the true vocal folds to the inferior margin of the cricoid cartilage. Subglottic stenosis is a narrowing of the subglottic larynx and manifests in the infant with respiratory distress and biphasic or primarily inspiratory stridor. It may be congenital or acquired. Symptoms often occur with a respiratory tract infection as the edema and thickened secretions of a common cold narrow an already compromised airway leading to recurrent or persistent croup-like symptoms.

Biphasic or primarily inspiratory stridor is the typical presenting symptom for congenital subglottic stenosis. The edema and thickened secretions of the common cold further narrow an already marginal airway that leads to croup-like symptoms. In a child with recurrent bronchiolitis, diagnosis of congenital subglottic stenosis should be considered. The stenosis can be caused by an abnormally shaped cricoid cartilage; by a tracheal ring that becomes trapped underneath the cricoid cartilage; or by soft tissue thickening caused by ductal cysts, submucosal gland hyperplasia, or fibrosis. Acquired subglottic stenosis refers to stenosis caused by extrinsic factors, most commonly resulting from prolonged intubation, and is discussed in further detail in Chapter 415 .

Diagnosis

The diagnosis made by airway radiographs is confirmed by direct laryngoscopy. During diagnostic laryngoscopy the subglottic larynx is visualized directly and sized objectively using endotracheal tubes ( Fig. 413.2 ). The percentage of stenosis is determined by comparing the size of the patients’ larynx to a standard of laryngeal dimensions based on age. Stenosis >50% is usually symptomatic and often requires treatment. As with all cases of upper airway obstruction, tracheostomy is avoided when possible. Subglottic stenosis is typically measured using the Myer-Cotton system, with grade I through grade IV subglottic stenosis indicating the severity of narrowing. Dilation and endoscopic laser surgery can be attempted in grade I and II, although they may not be effective because most congenital stenoses are cartilaginous. Anterior cricoid split or laryngotracheal reconstruction with cartilage graft augmentation is typically used in grade III and IV subglottic stenosis. The differential diagnosis includes other anatomic anomalies, as well as a hemangioma or papillomatosis.