Choanal Atresia

Choanal atresia, a rare anomaly, with a reported incidence of 1 in 8000 births, involves occlusion of the posterior nares by a membranous (10%) or bony (90%) septum ( Fig. 36-2 ). Unilateral lesions typically can be asymptomatic, but bilateral lesions may cause total airway obstruction because neonates are preferential nasal breathers. Symptoms are most evident when a baby is at rest, because when agitated and crying, the infant breathes via the oropharynx. Associated anomalies include esophageal atresia, congenital cardiac lesions, colobomata, and Treacher Collins syndrome, among a large number of rarer associations. Diagnosis can be made by the inability to pass a catheter through the nostrils into the oropharynx. Management ranges from simple placement of an oropharyngeal airway to operative opening of the occlusion with placement of stents. Rarely, tracheostomy may be needed if definitive surgical correction cannot be performed in the neonatal period.

Choanal atresia. A, Endoscopic view. B, Nasopharyngeal view.

Macroglossia

The tongue is often a site of obstruction. Stridor in a neonate can occur if the tongue is disproportionately larger than the infant’s oropharynx. Physical examination confirms the diagnosis. Insertion of an oral airway is usually successful in treating this type of airway obstruction. Several well-known syndromes include macroglossia as a component.

Beckwith-Wiedemann Syndrome

Severe hypoglycemia, in many cases secondary to hyperinsulinemia, initially brought these examples of infantile gigantism to medical attention. Macroglossia secondary to muscular hypertrophy, visceromegaly, microcephaly, and a series of umbilical abnormalities ranging from congenital umbilical hernia to omphalocele also compose this syndrome. Affected infants may also demonstrate a facial nevus flammeus, renal medullary dysplasia, and a characteristic pit on the tragus of the ear. These babies are typically large for gestational age. The congenital stridor resulting from the enlarged tongue usually resolves rapidly with the insertion of an oropharyngeal airway. Little further diagnostic workup of the airway is necessary if the child is identified as having this syndrome.

Metabolic Disorders

Several neonatal metabolic disorders cause macroglossia and result in congenital stridor, the best known of which are hypothyroidism and glycogen storage disease. The large tongue, high nature of the airway obstruction, and findings consistent with the underlying condition should suggest the diagnosis and appropriate workup early in the course of the disease. The stridor in these babies is generally mild, usually successfully treated with an oropharyngeal airway, and disappears shortly after birth as the underlying condition is successfully treated. Diagnostic evaluation in these patients should be directed at the underlying metabolic disorder; little additional diagnostic work is needed for the tracheobronchial tree.

Down Syndrome (Trisomy 21)

Children affected by Down syndrome are easily identified by their constellation of abnormalities. Their relative macroglossia may result in a mild congenital stridor. Because of the reported association between Down syndrome and congenital subglottic stenosis, endoscopy may be necessary to establish the cause of the stridor.

Lingual Thyroid

Lingual thyroid can be a rare cause of oropharyngeal obstruction. Stertor in the presence of hypothyroidism, detected by persistent elevation of thyroid-stimulating hormone on routine neonatal screening, raises the suspicion of lingual thyroid, although other lesions are more commonly responsible. This condition occurs in just over 1 in 10,000 births.

Laryngoscopy is used to confirm a mass at the base of the tongue. Further characterization by CT scan and thyroid scintigraphy should be performed. Of note, the thyroid may continue to hypertrophy during early infancy and childhood. Respiratory complications associated with hypothyroidism, such as respiratory depression, may not occur until later.

Severe Bronchopulmonary Dysplasia

Although not generally reported and not often appreciated, macroglossia can develop in infants with severe bronchopulmonary dysplasia and worsen the chronic pulmonary compromise. The obstruction caused by this condition is the result of chronic hypoxia (similar to clubbing of the fingernails) and often heralds a poor outcome. The condition often contributes to compensated respiratory acidosis and is best treated by tracheostomy as opposed to surgical reduction of the tongue.

Craniofacial Dysmorphology Syndromes

The craniofacial dysmorphology syndromes range from unusual to extremely rare. All result in an obstruction located in the oropharynx. This is secondary to micrognathia with glossoptosis. Stridor varies from mild to severe, and it is important to identify the underlying problem, which is often genetic. More complete descriptions of these conditions can be found in texts on congenital malformations.

Pierre Robin Syndrome

Pierre Robin syndrome represents the most common craniofacial dysmorphology with micrognathia and glossoptosis. In addition to the aforementioned characteristics, approximately half of these babies also have cleft palates/cleft lip anomalies, perhaps attributable to protrusion of the tongue between the posterior palatine plates during embryologic development. This protrusion results in failure of normal midline fusion. Furthermore, the tongue often prolapses posteriorly, resulting in partial obstruction of the upper airway. During inspiration, negative pressure in the pharynx retrodisplaces the already enlarged tongue and this increases the degree of pharyngeal obstruction. Stridor consequently results in children with Pierre Robin syndrome, and they have particular difficulty with inspiration. The airway obstruction is usually resolved with insertion of an oropharyngeal airway, and these patients tend to breathe more comfortably in a prone position. Feeding may create further problems for these babies and necessitate special nipples or gavage nutrition.

Tracheostomies are rarely necessary in these cases and are to be avoided if at all possible because of the risks of airway occlusion and death. Surgical procedures such as glossopexy or creation of a lingual flap have been described as alternatives but are also seldom needed except in the most severe cases. The first few months of life are critical in determining the severity of a particular infant’s anomaly and its importance in the overall prognosis.

Treacher Collins Syndrome

Treacher Collins syndrome, also known as mandibulofacial dysostosis , is a variable and diffuse group of craniofacial anomalies. This syndrome is characterized by downward-sloping palpebral fissures, colobomata of the lower lids, sunken cheek bones, and blind fistulae on an angle between the mouth and the ears ( Fig. 36-3 ). Pinnae may be deformed, deafness is common, and micrognathia is part of the syndrome (usually less severe than that seen in Pierre Robin syndrome). The presumed genetic defect is autosomal dominant, with mutation in the TCOF1 gene at chromosome 5q32-q33.1.

Example of a child with Treacher Collins syndrome demonstrating sunken cheek bones, downward sloping palpebral fissures, and micrognathia.

The hypopharynx is the location of the obstruction in these children (as in children with Pierre Robin syndrome), owing to the disproportionate relationship between the small jaw and the large tongue. These cases of stridor can most often be managed medically, often with simple insertion of an oropharyngeal airway, and tracheostomy is seldom necessary. Rarely, bronchoscopy may be indicated if associated tracheobronchial tree anomalies are a concern, but these are quite unusual.

Hallermann-Streiff Syndrome

The Hallermann-Streiff syndrome is a rare syndrome that consists of microphthalmia, cataracts, blue sclerae, and nystagmus. Associated anomalies include a pinched nose, micrognathia, and hypertrichosis of the scalp, eyebrows, and eyelashes ( Fig. 36-4 ). Transmission is presumed to be autosomal dominant, although most cases are thought to represent de novo mutations. Congenital stridor in these infants arises from micrognathia with relative glossoptosis, and treatment is similar to that outlined for Pierre Robin or Treacher Collins syndrome.

Example of an infant with Hallermann-Streiff syndrome demonstrating microphthalmia, pinched nose, micrognathia, and hypertrichosis of the scalp.

Möbius Syndrome

Infants with the Möbius syndrome have a characteristic absence or maldevelopment of various cranial nerve nuclei. Cranial nerve VII (facial nerve) is the most commonly involved, but other cranial nerves such as cranial nerves V, VI, and VIII may also be affected. Common findings include facial paralysis, ptosis, ophthalmoplegia, clubbed feet, and syndactyly. It is presumed that this condition is inherited in an autosomal dominant manner.

Paralysis of the facial nerve is the cause of upper airway obstruction as well as difficulties with mastication and deglutition. Both inspiratory and expiratory components of stridor result from the relatively fixed nature of the obstruction. Tracheostomy may be required in severe cases. Many children, however, can be successfully treated by parental instruction in very careful feeding techniques.

Freeman-Sheldon Syndrome

Infants with Freeman-Sheldon syndrome are often called “whistling-faced” children. They have hypoplastic alae nasi, clubbed feet, and masklike whistling facies. Their eyes are deep set with blepharophimosis, ptosis, and strabismus. Transmission is autosomal dominant with some variations that transmit as autosomal recessive. Chromosomal abnormalities have been reported at both 11p15.5 and 17p13.1. These children are classified as having a type of distal arthrogryposis.

Stridor in these children is the result of air passage through a narrow channel. Although the sound may be alarming, it usually does not require intervention.

Nager Syndrome

Nager syndrome is a rare acrofacial dysostosis that presents with upper limb malformation, mandibular and malar hypoplasia, downward-slanting palpebral fissures, absent eyelashes in the medial third of the lower lids, dysplastic ears with conductive deafness, and variable degrees of palatal clefting. This syndrome is associated with chromosome 9 defects. Airway obstruction in these patients is related to posterior tongue displacement due to hypoplasia of the mandible. Acute management often requires early tracheostomy, and subsequent mandibular distraction is eventually needed to correct the defect.

Laryngeal Atresia

The most extreme form of obstruction at this level, laryngeal atresia, results in a desperate emergency during the first few moments of life. This lesion was originally described in 1826, but only 51 cases were reported in the subsequent 160 years. Very few of these patients survive because surgical intervention to secure a definitive airway must occur within 2 to 5 minutes of clamping of the umbilical cord.

The most dramatic physical finding is that the child is aphonic, with absence of any cry or gasp at birth. If the lesion is immediately recognized on direct laryngoscopy, an emergency cricothyroidotomy should be performed. Diagnosis of laryngeal atresia has now been reported prenatally, and in the future, clinicians may be able to prepare for emergent airway management at birth or schedule the child for an ex utero intrapartum treatment procedure followed by emergent airway opening.

Laryngeal Web

Laryngeal webs account for approximately 5% of laryngeal anomalies ( Fig. 36-5 ). These lesions arise about the 10th week of intrauterine life and probably represent an arrest of the development of the larynx in the area near the vocal cords. Seventy-five percent of these lesions occur at the level of the cords; the rest are subglottic or supraglottic in about equal numbers. The web generally occurs anteriorly, and the lesions are often asymptomatic if they extend less than halfway back along the cords. Because the glottic area is triangular, these anteriorly placed webs reduce the glottic area by only 15% to 20% and are usually not sufficient to cause stridor.

Endoscopic view of neonatal larynx with partial laryngeal atresia and a laryngeal web partially obstructing the laryngeal orifice.

If the web extends posteriorly, the symptoms may be marked. The stridor is primarily inspiratory but often has an expiratory component. The affected infant’s cry is hoarse and weak; the child is rarely aphonic and often is dyspneic at rest.

Laryngoscopy and bronchoscopy should be performed as soon as possible. If a thin, transparent web is encountered at the level of the cords, it may be easily swept away with the bronchoscope, completely correcting the problem. Completion of the bronchoscopy should be performed to rule out associated anomalies beneath the area of the web.

If the web is thick and fibrous, no attempt should be made to force the bronchoscope through the area. This kind of web is often encountered in the subglottic region. Tracheostomy is the treatment of choice if the child is dyspneic and unable to tolerate the web. If aeration of the child is satisfactory despite the stridor, as evidenced by arterial blood gas determinations, simple observation may be sufficient management until the baby is able to undergo surgical repair. This is usually deferred until the child is 18 to 24 months of age. The best results to date have been achieved in those children who undergo a meticulous removal of the thick fibrotic web. Depending on the thickness of the web, laser therapy is an alternative and may yield superior results in the future.

Congenital Vocal Cord Paralysis

Congenital vocal cord paralysis is the second most common cause of congenital stridor. In the past, birth trauma was frequently implicated in the etiology of the paralysis but now appears to be a declining cause. Intracranial lesions and the possibility of congenital cardiac lesions, especially one impinging on the recurrent laryngeal nerve, must be considered.

Fortunately, paralysis is unilateral in 70% to 80% of cases. Some studies report that both sides are equally involved, but left-sided paralysis is typically associated with underlying congenital cardiac anomalies. These infants have a hoarse and weak cry, and if the paralysis is bilateral, these children may be truly aphonic. The inspiratory stridor is obviously worse in bilateral paralysis. Marked suprasternal and intercostal retractions may be present in these children.

Diagnosis is rapidly made by laryngoscopy, and treatment depends on the severity of the problem. In a unilateral paralysis with minimal or no dyspnea, simple observation is appropriate. Bilateral paralysis, generally associated with severe symptoms, necessitates tracheostomy. Once the airway is adequately secured, the cause of the paralysis can be explored. If the causal lesion can be identified and corrected, the stridor may improve. If no lesion can be found or if it cannot be safely corrected, later fixation of the arytenoids with the vocal cord in abduction may result in satisfactory control of the stridor and decannulation.

Laryngomalacia

Laryngomalacia is the most common cause of congenital stridor, accounting for 60% to 75% of cases of stridor in newborns. It also accounts for three-fourths of the congenital laryngeal abnormalities. The pathophysiology of this condition involves an immature, floppy larynx that collapses during each inspiration ( Fig. 36-6 ), producing an inspiratory stridor of varying severity that is often much worse when the baby is agitated or screaming. Some infants improve at night, but others experience a worsening of their respiratory sounds.

Endoscopic view of immature floppy glottis characteristic of laryngomalacia. Dynamic examination demonstrates downward placement of glottis into larynx with inspiration.

Laryngomalacia occurs with a 2:1 male-to-female predominance and is usually present at birth. Despite most cases being present at birth, for up to a quarter of patients, the first symptoms appear during the first or second week of life. Many cases are reported to have micrognathia, and some may be confused with Pierre Robin syndrome.

Diagnosis is made easily by laryngoscopy, which shows a soft, enfolded epiglottis. The larynx is often difficult to expose and is found high under the tongue. Bronchoscopy should accompany laryngoscopy to rule out associated anomalies or extensive malacia, such as tracheomalacia and/or bronchomalacia.

Maturation of the epiglottis by the age of 18 to 24 months usually results in resolution of the stridor. Accordingly, tracheostomy is not typically necessary in the final treatment of this disorder.

Congenital Subglottic Stenosis

The overall incidence of congenital subglottic stenosis is unknown because many such cases remain undiagnosed. It has been estimated that 39% of all subglottic stenoses are congenital (the remaining group being acquired). The stenotic area is typically found 2 to 3 mm below the vocal cords and may reduce the subglottic area to 3 to 3.5 mm. The proposed cause of the congenital group is arrested development of the conus elasticus or the cricoid.

The stridor, if present at all, is usually biphasic and sometimes arises during the first or second month of life. Respiratory distress after an upper respiratory tract infection is typically the presenting symptom. These patients are generally unable to clear the resultant increased secretions found in association with infection. Affected children are often treated for recurrent pneumonias or prolonged tracheobronchitis. Many cases are not discovered until a severe episode of croup or epiglottitis results in emergency intubation or tracheostomy.

Mild lesions should be observed, and antibiotic therapy should be added during periods of upper respiratory tract infection. Tracheostomy is necessary in more than half the cases of children with severe stenosis and marked symptoms. Once the tracheostomy is in place, dilation during monthly serial laryngoscopy under general anesthesia often results in improvement. The dilation must be gentle to prevent further damage or fibrosis of the subglottic region. For more severe degrees of stenosis, open surgical intervention may be necessary. The outcome in this congenital group of subglottic stenosis is quite good, with 82% of patients in one large series successfully decannulated after one procedure.

Acquired Subglottic Stenosis

Acquired subglottic stenosis is most often caused by prolonged endotracheal intubation. Because of the increased survival of neonates with respiratory difficulties requiring intubation (especially extremely low birth-weight infants), this lesion is increasing in frequency as a cause of stridor. A protracted form of acquired subglottic stenosis was found to occur in 8.3% of neonates surviving a period of endotracheal intubation in one study. In its mildest form, the stenosis consists of laryngeal edema and has been reported in 30% of infants immediately after intubation. Stridor in these patients is inspiratory and presents with the first breaths after tube removal. This usually resolves within 72 hours. During this 3-day period, head elevation, humidified air, racemic epinephrine, nasal CPAP or noninvasive nasal ventilation, and occasionally systemic steroids are used to treat the mild form of this disorder.

In its most severe form, acquired stenosis is a dense scar of well-organized fibrous tissue. This lesion may require tracheostomy before the actual stenosis can safely be manipulated. Initial treatment includes graded, gentle dilation with or without intralesional steroids. As many as half of the stenotic scars will improve and often stabilize after four to six treatments. Failure to achieve significant improvement by then indicates the need for more aggressive treatment such as cryosurgery, laser ablation, cricoid split procedure, or resection and reconstruction with stents. There have been reasonable results with the cricoid split procedure and intubation during healing rather than recourse to tracheostomy, and this alternative should always be considered.

Laryngeal Cleft

Although laryngeal clefts were once considered extremely rare lesions, they have frequently been reported since 1990. This is probably a result of enhanced endoscopy techniques and improved ability to make the diagnosis in the antemortem period. The lesion forms owing to a failure of dorsal fusion during the chondrification of the cricoid cartilage. A midline cleft thus remains posteriorly and extends down between the arytenoids into the upper portion of the esophagus and trachea. Affected children are often very stridorous at birth, and many have died in the past because of inadequate resuscitation. In addition to their respiratory difficulties, aspiration and pneumonitis occur if these patients are fed without regard for their clefts. Consequently, they require recognition, intubation, and stabilization. A feeding gastrostomy and possible fundoplication are often necessary until definitive repair can be performed. Once extubation is accomplished, close observation is necessary to ensure that upper airway secretions do not continuously pass into the lungs. If this proves to be a severe and ongoing problem that precipitates recurrent pneumonia and respiratory distress, it may be necessary to place a tracheostomy until surgical closure of the cleft can be achieved.

Subglottic Hemangioma

Hemangiomas are another cause of congenital subglottic obstruction. The onset of symptoms is variable, as symptomatology is related to the growth and development of these lesions. The lesions are at first quite small and may have a period of rather rapid growth, followed by a long plateau and slow involution. Time to presentation for patients with subglottic hemangiomas depends upon the age at which the hemangioma develops. If the hemangioma develops early in fetal life, then the patient will become symptomatic earlier in life. On the other hand, if the subglottic hemangioma develops after birth, there may be several months’ lag in the time to presentation of symptoms. Hemangiomas on other areas of the body suggest the possibility of subglottic hemangioma; definitive diagnosis is made by laryngoscopic and bronchoscopic examination.

A bronchoscopic finding of a red or purple mass just beneath the cords is generally considered diagnostic. Most pediatric surgeons believe that biopsy is contraindicated when such findings are seen, because hemorrhage necessitating emergent surgery is a distinct possibility after biopsy. Once the diagnosis is established, appropriate therapy is chosen according to the severity of symptoms. If the child is stable and has normal blood gas values at rest, observation is sufficient. If the obstruction is significant enough to result in dyspnea, severe stridor, and possibly abnormal blood gas values, tracheostomy below the lesion should be considered. One must also be aware of the possibility of platelet trapping (Kasabach-Merritt syndrome) before surgical intervention.

It is questionable whether radiation should be used in the treatment of these children today because of the risk of thyroid malignancy. Prednisone, 2 to 4 mg/kg per day, and β-blockers, such as propranolol, are quite beneficial if the hemangioma is growing quickly and causing thrombocytopenia. The side effects of interferon-α are so substantial as to preclude use in most cases as of this writing. Dramatic regression of the hemangioma and prompt correction of the thrombocytopenia with the use of these agents have been reported, although both have also been associated with significant side effects.

Intrinsic Tracheal Compression

Tracheomalacia

Tracheomalacia results from a failure of the cartilaginous rings to fully support the round shape of the normal trachea. The cartilages are hypoplastic and allow the trachea to collapse, especially during expiration ( Fig. 36-7 ). This condition is commonly seen in babies and children undergoing bronchoscopic evaluation but is only incidentally responsible for stridor in a moderate number of them. Because obstruction of the airway tends to occur as the trachea collapses with expiration, stridor occurs at that time. The condition is diffuse and usually occurs throughout the length of the trachea.

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