Upper Airway Disease

Etiology.

Laryngomalacia is abnormal laxity of the pharyngeal tissues that causes the epiglottis, arytenoids, and aryepiglottic folds to involute and partially obstruct breathing during inspiration. The underlying cause of laryngomalacia is attributed to the immaturity of the laryngeal cartilages and muscles, which allows the larynx and the supralaryngeal structures to collapse. The unstable epiglottis and redundant arytenoid cartilage mucosa tend to be sucked into the glottis during inspiratory airflow causing obstruction. Laryngomalacia accounts for more than 75% of cases of congenital stridor and is the most common cause of symptomatic partial upper airway obstruction in infants. The stridor typically improves when the infant is agitated or active and becomes worse when the infant is at rest.

Imaging.

The diagnosis of laryngomalacia can be established with use of airway fluoroscopy, although laryngoscopy is the diagnostic procedure of choice. The characteristic imaging finding in patients with laryngomalacia consists of downward and posterior bending of the epiglottis and anterior buckling of the aryepiglottic folds, which narrow and eventually obliterate the upper airway ( Fig. 51.1 ). Although airway fluoroscopy appears to be reliable because of its high specificity, it has low sensitivity, and thus negative findings of a fluoroscopic study require further diagnostic evaluation in the setting of a high clinical suspicion.

Treatment and Follow-up.

In most infants with laryngomalacia, stridor resolves during the first year of life. However, potentially serious complications, including airway obstruction and sudden death, may occur. In severe or life-threatening cases, various surgical treatment options are available including supraglottoplasty, an incision in the aryepiglottic folds, epiglottopexy, and tracheostomy.

Etiology.

Acute bacterial epiglottitis is a potentially serious cause of upper airway obstruction in children. It is characterized by inflammation and swelling of the epiglottis and the aryepiglottic folds but also can affect the false cords and the subglottic region. Epiglottitis usually is attributed to Haemophilus influenzae , although other bacteria including Streptococcus, Staphylococcus, Moraxella, and Pseudomonas also have been implicated. Because H. influenzae is now preventable by immunization, the incidence of epiglottitis has substantially diminished, although vaccine failures do occur. Epiglottitis typically occurs in children between 3 and 6 years of age, but it also can occur in adults. Epiglottitis usually has a sudden onset with no history of a preceding upper respiratory tract infection. Affected children typically appear toxic with acute stridor, dysphagia, fever, restlessness, drooling, and increased respiratory distress in the recumbent position. Epiglottitis is a life-threatening disease that requires potential emergent intubation.

Imaging.

Epiglottitis usually is diagnosed with radiography, and endoscopy is obtained for confirmation. A lateral radiograph reveals swelling and marked enlargement of the epiglottis that resembles the shape of a thumb ( Fig. 51.2 ). Associated thickening of the aryepiglottic folds also occurs. Inflammation extends into the glottis and subglottic regions, causing a steeple or funnel configuration of the airway on frontal views. Because of the potentially rapid progression of the condition, which can lead to sudden and complete obstruction of the upper airway, radiographs should be obtained expeditiously with minimal manipulation of the neck. When undergoing imaging, patients should remain upright in their position of maximal comfort. Conditions that mimic bacterial epiglottitis in children include caustic ingestion, angioneurotic edema, chemical or thermal injury, abscess, and epithelial cyst, among others. The omega epiglottis with prominent lateral folds is a normal variant and should not be misinterpreted as epiglottitis. In such cases, the aryepiglottic folds remain thin.

Treatment and Follow-up.

Antibiotic therapy is a mainstay of treatment, and steroids are administered to some patients. Direct laryngoscopy with intubation is performed to secure the airway in severely affected patients.

Etiology.

Laryngeal atresia, a rare congenital malformation, is usually fatal. The malformation is caused by nondevelopment of the sixth branchial arch during embryogenesis, resulting in failure of the larynx and the trachea to recanalize. Typical presentation of affected patients with laryngeal atresia at birth is severe respiratory distress despite strong respiratory effort. Associated anomalies include a tracheoesophageal fistula, esophageal atresia, urinary tract abnormalities, limb defects, and low-set ears. Laryngeal atresia is the most common reason for congenital high airway obstruction syndrome (CHAOS), a rare entity causing fluid entrapment within the enlarged trachea and lungs along with flattening of the diaphragm (see also Chapter 50 ).

Imaging.

Laryngeal atresia can be diagnosed with use of prenatal ultrasound by identifying the signs of congenital high airway obstruction syndrome, such as enlarged hyperechogenic lungs, a flattened or inverted diaphragm, a dilated and fluid-filled trachea, fetal hydrops, and polyhydramnios. Fetal magnetic resonance imaging (MRI), which correlates highly with prenatal ultrasound, can detect laryngeal atresia with the advantage of having the capability to identify the level of obstruction in most cases ( e-Fig. 51.3 ).

Treatment and Follow-up.

The treatment of laryngeal atresia focuses on prompt airway intervention at delivery after an accurate prenatal diagnosis, which may allow survival of infants with this otherwise fatal condition. An emergent tracheostomy is required immediately after birth to secure an airway. Ex utero intrapartum treatment (EXIT) procedure has also been used for this condition to facilitate safe delivery and allow some time to secure the airway. Repair of laryngeal atresia requires laryngotracheal reconstruction.

Etiology.

A congenital laryngeal web is an uncommon condition caused by faulty embryogenesis of the laryngotracheal groove. This web is a band of varying thickness, usually located anteriorly at the level of the cords, which obliterates the anterior commissure. A congenital laryngeal web occasionally occurs just below the true cords. Affected infants present with a weak or absent cry, varying degrees of stridor, and respiratory distress; they often have concomitant abnormalities such as subglottic stenosis.

Imaging.

A definitive diagnosis of laryngeal web can be provided by direct laryngoscopy, but imaging evaluation plays a role in diagnosis. Plain radiography and fluoroscopy can demonstrate that the abnormality is in the glottis region, but no definitive radiographic findings exist. Computed tomography (CT) with multiplanar imaging and three-dimensional reconstructions can provide precise information with respect to the exact location of the web, its thickness, and extent ( Fig. 51.4 ). Furthermore, CT is able to visualize the structures beyond the area of obstruction, which is a limitation of laryngoscopy.

Treatment and Follow-up.

The primary goals of treatment for a congenital laryngeal web are to provide a patent airway and achieve sufficient voice quality. Treatment depends on the thickness and extent of the abnormality. Surgical procedures include laryngotracheal reconstruction, laryngofissure and placement of a stent or keel, and endoscopic lysis with application of mitomycin C.

Etiology.

A laryngocele is a rare lesion characterized by abnormal dilation of the laryngeal saccule, which is a narrow blind pouch arising from the anterior end of the laryngeal ventricle. Laryngoceles may extend internal or external to the larynx.

Most childhood laryngoceles are congenital; acquired laryngocele may develop in older children or adults who experience increased intralaryngeal pressure.

Imaging.

CT and MRI have replaced older plain film and fluoroscopic techniques. A laryngocele typically is a well-defined cystic structure of air or near-water density value in a characteristic location, with a smooth surface, lack of mucosal abnormality, and variable extent of airway narrowing ( Fig. 51.5 ).