33. Laryngeal Trauma

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Current Otolaryngology  > VIII. Larynx & Hypopharynx > Chapter 32. Stridor in Children >

Stridor in Children: Introduction

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 321). This chapter describes the more common laryngeal abnormalities that can cause stridor.

Table 321. Causes of Airway Obstruction in Infants and Children.

	Congenital	Acquired
Supralaryngeal	Choanal atresia Craniofacial abnormalities Retrognathia Macroglossia	Adenotonsillar hypertrophy Foreign body Retropharyngeal abscess Ludwig's angina
Laryngeal	Laryngomalacia Laryngeal cysts Laryngeal webs Posterior laryngeal cleft Vocal cord paralysis Cricoarytenoid joint fixation Subglottic hemangioma	Iatrogenic (surgical and intubation traumas)    Laryngeal webs    Subglottic stenosis Vocal cord paralysis Inflammatory    Epiglottitis    Laryngotracheobronchitis    Hereditary angioedema Neoplasms    Respiratory papillomatosis    Rhabdomyosarcoma External compression    Thyroid    Cystic hygroma Foreign bodies Burns (caustic and thermal) External trauma
Tracheal	Tracheobronchomalacia Stenosis Vascular compression    Aberrant innominate artery    Double aortic arch    Pulmonary artery sling Tracheal cysts	Laryngotracheobronchitis Bacterial tracheitis Foreign bodies External compression    Thyroid    Cystic hygromas    Mediastinal tumors

Laryngomalacia

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 exact mechanism by which laryngomalacia develops is not completely understood . 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 321). 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. Other factors that have been implicated in the etiology of laryngomalacia include abnormally pliable supraglottic cartilage, neuromuscular abnormalities, and gastroesophageal reflux.

Figure 321. 

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 1245% 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 the ensuing months becomes gradually more pronounced, usually peaking at the age of 69 months. Spontaneous improvement then occurs and symptoms usually completely resolve by the age of 18 months to 2 years of age, although persistent cases beyond age 5 have been reported. Stridor is not constantly present; rather, it is intermittent and variable in intensity. Typically, symptoms are worse during sleep, and positional variations occur; stridor is worse when the patient is in the supine position and is improved when the patient is prone. Both feeding and exertion tend to result in more pronounced stridor. Although an infant with laryngomalacia usually has a normal cry, stridor may be exacerbated by crying owing to a more forceful inspiratory effort. In most cases, symptoms are mild and self-limiting, but a small proportion of cases have severe stridor, apneic episodes , feeding difficulties, and failure to thrive.

Clinical examination of the patient may reveal no abnormality. If the infant is sleeping or crying, then stridor is more likely to be observed and its associated signs, such as tachypnea and intercostal and subcostal recessions, should be sought. Cyanosis is extremely unusual in laryngomalacia and should raise the suspicion of some other pathology.

Evaluation

Endoscopy

The use of a flexible fiberoptic endoscope under local anesthesia has been suggested. This procedure is safe and allows a dynamic assessment of the glottis and supraglottis and avoids the risks associated with general anesthesia.

Laryngotracheobronchoscopy

Laryngotracheobronchoscopy is often considered an essential study before a definitive diagnosis can be made in order to rule out any synchronous airway pathology.

Polysomnography

In severe cases, polysomnography can be performed to detect episodes of hypoxia or hypercapnia. The results of this study can influence the decision to undertake surgical management of the condition.

Treatment

In most patients , laryngomalacia is a self-limiting condition that does not result in any harm to the patient; therefore, observation is all that is required. In the most severe cases of laryngomalacia, which is encountered in a small percentage of patients, a temporary tracheotomy may be unavoidable.

Surgical intervention is indicated for approximately 10% of patients. The main indications for surgery are severe stridor, apnea, failure to thrive, pulmonary hypertension, and cor pulmonale. A variety of procedures have been described for the treatment of laryngomalacia (referred to as supraglottoplasty), which are largely aimed at reduction of the redundant laryngeal mucosa. These procedures include (1) division of the aryepiglottic folds, (2) excision of a wedge of the aryepiglottic fold with or without trimming the arytenoids or the lateral border of the epiglottis, and (3) suturing of the epiglottis to the base of the tongue. There is disagreement as to whether microdissection or laser surgery is the optimum treatment modality. Physicians who favor laser surgery contend that bleeding is less of a problem compared with microdissection; physicians who favor microdissection maintain that the risk of postoperative scarring is greater with the use of laser.

Complications of supraglottoplasty include bleeding, aspiration, and supraglottic scarring. The risk of supraglottic stenosis is lessened by excising the least amount of supraglottic mucosa to produce an improvement in symptoms. Scarring is particularly problematic in the interarytenoid region; therefore, an island of mucosa must be left in this area.

High rates of reflux have been demonstrated in patients with laryngomalacia, and it has therefore been implicated as a causative factor. However, the relationship remains unproven; hence the controversy in the antireflux medication for laryngomalacia.

Loke D, Ghosh S, Panarese A, Bull PD. Endoscopic division of the aryepiglottic folds in severe laryngomalacia. Int J Pediatr Otorhinolaryngol. 2001;60:59. ( Presents results of simple division of the aryepiglottic folds for laryngomalacia, concluding that this is sufficient in all but the most severe cases.) [PMID: 11434955]

Masters IB, Chang AB, Patterson L et al. Series of laryngomalacia, tracheomalacia, and bronchomalacia disorders and their associations with other conditions in children. Pediatr Pulmonol. 2002;34(3):189. (Describes the association of respiratory malacia with other anomalies.) [PMID: 12203847]

Rosbe KW, Kenna MA, Auerbach AD. Extraesophageal reflux in pediatric patients with upper respiratory symptoms. Arch Otolaryngol Head Neck Surg. 2003;129(11):1213. (Review of the evidence for reflux in pediatric airway pathologies.) [PMID: 14623753]

Laryngeal Cysts

Laryngeal cysts are a rare cause of stridor in infants. The two main types of laryngeal cysts are ductal and saccular cysts. Ductal cysts are more common and are thought to originate from obstruction of the submucous glands. They can arise anywhere in the larynx, but are most commonly found in the supraglottis. Saccular cysts arise in the laryngeal ventricle and are usually congenital in infants. Unlike laryngoceles, which usually present in adults, saccular cysts do not communicate with the laryngeal lumen.

The most common symptoms arising from laryngeal cysts are stridor, feeding difficulties, and cyanotic episodes. Laryngeal cysts can usually be managed by endoscopic de-roofing or excision.

Vocal Cord Paralysis

Essentials of Diagnosis

(1) Unilateral Vocal Cord Paralysis

• Hoarse or breathy voice/cry.
• Mild dyspnea, stridor, or both.
• Aspiration.
• Spontaneous improvement or resolution.

(2) Bilateral Vocal Cord Paralysis

• Severe stridor.
• Aspiration.
• Usually requires tracheotomy.

General Considerations

Vocal cord paralysis in infants and children can be either congenital or acquired and either unilateral or bilateral. It is the second most common congenital abnormality of the larynx, accounting for approximately 10% of cases. Congenital vocal cord palsy is slightly more common in males and is more commonly bilateral.

There are many causes of acquired vocal cord palsy (Table 322), although most commonly the paralysis is idiopathic. Central nervous system (CNS) abnormalities usually result in bilateral vocal cord palsy. The most common congenital CNS abnormality resulting in vocal cord palsy is the Arnold-Chiari malformation. Acquired CNS causes of vocal cord paralysis are rare in infants and children, as are acquired peripheral neuropathies. Congenital abnormalities of the heart and great vessels may lead to vocal cord palsy, or the paralysis may result from surgery to correct these abnormalities. In this situation, the left side is more commonly affected because of the longer course of the left recurrent laryngeal nerve through the mediastinum . Rarely, esophageal surgery, such as repair of a tracheoesophageal fistula, can result in a bilateral palsy. Other traumatic causes of vocal cord paralysis include birth trauma, intubation, and head injury . Inflammatory conditions such as encephalopathies and Guillain-Barr usually produce bilateral vocal cord paralysis. Neoplastic causes of vocal cord palsy are rare in infants and children. Familial X-linked vocal cord paralysis has been reported, but is extremely rare.

Table 322. Etiology of Acquired Vocal Cord Paralysis.

Idiopathic  

Central nervous system  

  Arnold-Chiari malformation

  Hydrocephalus

  Encephalocele

  Syringomyelia or syringobulbia

Peripheral nervous system  

  Myasthenia gravis

  Myotonic dystrophy

  Charcot-Marie-Tooth disease

Trauma  

  Surgical

  Head injury

  Endotracheal intubation

  Birth trauma

Neoplasia  

  Thyroid carcinoma

Inflammatory  

  Viral

  Bacterial

  Granulomatous

Cardiovascular anomalies  

  Tetralogy of Fallot

  Cardiomegaly

  Patent ductus arteriosus

  Vascular rings

Clinical Findings

Symptoms and Signs

The symptoms arising from vocal cord palsy vary widely. Patients may be asymptomatic, or they may have an acute airway obstruction that requires emergency intervention. Patients with unilateral vocal cord palsy do not usually have signs of airway obstruction; therefore, stridor is not a common feature, although dyspnea may occur. More often the presenting features are a hoarse, breathy voice or cry and a weak cough. Feeding problems and aspiration are more likely to occur if the lesion is proximal to the superior laryngeal nerve since this nerve supplies sensation to the supraglottis. Bilateral vocal cord paralysis tends to have more pronounced symptoms such as stridor, apnea, and cyanosis; however, if the vocal cords lie in the intermediate position, then airway obstruction does not occur and aspiration is the primary problem.

Evaluation

If any doubt about the stability of the airway exists, then the patient should be evaluated in the operating room and the airway secured before further investigation is considered.

Although fiberoptic endoscopy can reliably demonstrate a vocal cord palsy, the airway needs to be assessed by laryngotracheobronchoscopy for two reasons: (1) The arytenoid cartilage must be palpated to exclude the rare finding of a fixed cricoarytenoid joint. (2) The possibility of synchronous pathology in the airway must be excluded.

If a cause is not apparent, then a magnetic resonance imaging (MRI) scan including the brain, brainstem, neck, and chest (the course of the vagus and recurrent laryngeal nerves) should be performed. In patients in whom aspiration is suspected, a contrast swallow or videofluoroscopy can provide information on deglutition and laryngeal penetration. Functional endoscopy evaluation of swallowing (FEES) is also used in the pediatric group .

Treatment

The function of the glottis is to protect the lungs from the aspiration of food while providing an adequate airway. A secondary, though important, function is to provide a voice. Management decisions are influenced by the underlying cause (if known), the severity of symptoms, and the likelihood of spontaneous recovery. Spontaneous recovery occurs more frequently in acquired than in congenital vocal cord palsy, and it is also more likely in unilateral than bilateral vocal cord palsy.

Unilateral Vocal Cord Paralysis

Most children with unilateral vocal cord paralysis have minimal symptoms because the normal vocal cord adopts a more medial position to compensate for the paralyzed vocal cord. If poor voice quality is persistent, then speech therapy is the preferred treatment. In the rare instance in which the airway is significantly compromised, tracheotomy is indicated. Successful decannulation without the need for further laryngeal surgery is usually possible as the larynx develops.

Bilateral Vocal Cord Paralysis

In children with bilateral vocal cord palsy, the vocal cords usually lie in the adducted position, which results in a compromised airway. This circumstance indicates that the majority of cases of bilateral vocal cord palsy will require a tracheotomy to maintain the airway. Once a tracheotomy has been performed, serial endoscopy should be planned to monitor any spontaneous recovery of vocal cord function. It is recommended that irreversible surgical procedures on the larynx are not considered for at least 1 year after a tracheotomy. Some otolaryngologists prefer to wait until the child is old enough to make his or her own decision about further surgery. The aim of surgery for permanent bilateral vocal cord palsy is to produce an airway of sufficient size to allow decannulation without compromising the protective function of the larynx or producing an unacceptable voice quality. Various surgical techniques have been described to accomplish this goal. Excisional techniques simply remove tissue from the glottis to produce an improved airway. Lateralization techniques mechanically fix the vocal cord in a more abducted position. Neuromuscular techniques partially reinnervate the intrinsic muscles of the larynx, particularly the posterior cricoarytenoid muscle, thereby restoring a degree of active abduction.

Brigger MT, Hartnick CJ. Surgery for pediatric vocal cord paralysis: a meta-analysis. Otolaryngol Head Neck Surg. 2002; 126(4):349. (Meta-analysis of current surgical treatments for bilateral vocal cord paralysis.) [PMID: 11997772]

Friedman EM, De Jong AL, Sulek M. Pediatric vocal fold immobility: the role of the carbon dioxide laser posterior transverse partial cordotomy. Ann Otol Rhinol Laryngol. 2001;110:723. (Describes an excisional surgical technique modified for use in pediatric patients with bilateral vocal cord palsy.) [PMID: 11510728]

Parikh SR. Pediatric unilateral vocal fold immobility. Otolaryngol Clin North Am. 2004;37(1):203. (General review of unilateral vocal cord palsy including the diagnosis and the management.) [PMID: 15062694]

Congenital Laryngeal Webs

Laryngeal webs are thought to arise from a failure of complete recanalization of the larynx in the embryo. Although webbing can occur at all levels in the larynx, it is most commonly seen in the anterior glottis. When webbing is severe, it is often associated with subglottic stenosis. Complete atresia of the larynx is extremely rare and requires immediate tracheotomy at birth.

The most common presenting symptoms are an abnormal cry and stridor. The diagnosis is made at endoscopy, and other airway abnormalities should be excluded. Small, thin webs usually respond to simple incision. More severe webbing may require an excision via a laryngofissure approach, with insertion of a stent.

Posterior Laryngeal Clefts

A posterior laryngeal cleft is a rare congenital abnormality that occurs as a result of the failure of fusion of the posterior larynx and, in some cases, the trachea. The abnormality is classified according to the extent of the cleft (Figure 322). The predominant symptoms are hoarseness and aspiration; stridor is a rare feature. The severity of symptoms varies and depends on the extent of the abnormality. Type I clefts often have minimal symptoms, whereas Type IV clefts produce severe aspiration pneumonia and carry a poor prognosis even if surgical closure is attempted.

Figure 322. 

Classification of posterior laryngeal clefts. Type I: Interarytenoid cleft; superior to the glottis. Type II: Partial cricoid cleft; extends inferior to the glottis and partially through the posterior lamina of the cricoid. Type III: Total cricoid cleft, with or without extension into the cervical tracheoesophageal wall. Type IV: Laryngotracheoesophageal cleft extending beyond the thoracic inlet.

The diagnosis of posterior laryngeal clefts is made by demonstrating penetration of the larynx on contrast swallow, and the presence of a cleft is confirmed at endoscopy. Mild clefts may require no treatment other than the thickening of feeds; however, if aspiration persists, then endoscopic closure should be considered. More extensive clefts require surgical closure using either a lateral pharyngotomy or laryngofissure approach.

Laryngeal Foreign Bodies

Most inhaled foreign bodies pass through the larynx and trachea and become lodged distally. There is often a history of the child having something in the mouth, commonly a peanut , before the onset of symptoms. If a foreign body becomes lodged in the larynx and causes complete obstruction, it will cause sudden death unless removed immediately. If the airway is only partially obstructed, then stridor, hoarseness, and cough are the predominant symptoms. If the object is radiopaque, its site of impaction can be confirmed by x-ray. Removal under general anesthesia is generally required.

Subglottic Stenosis

Essentials of Diagnosis

(1) Congenital Subglottic Stenosis

• Stridor at birth, if moderate to severe stenosis.
• Intermittent stridor, associated with respiratory tract infections, if mild stenosis.

(2) Acquired Subglottic Stenosis

• Commonly as a consequence of prolonged endotracheal intubation.
• Presents with repeated failure of attempted extubation, or with gradual onset of stridor following extubation.

General Considerations

The subglottis is the narrowest portion of the airway in children, and the cricoid cartilage is the only complete cartilaginous ring in the airway. Because airflow in a cylinder is directly proportional to the fourth power of the radius, even a slight reduction in the area of the subglottis can lead to significant obstruction.

The Myer-Cotton grading system describes the severity of stenosis according to the percentage of subglottic stenosis present (Figure 323). The percentage is calculated by measuring the largest sized endotracheal tube that can be passed through the subglottis and comparing this with the age-appropriate tube size for the child. A subglottic diameter of 4 mm in a full-term neonate is considered to be abnormal.

Figure 323. 

Myer-Cotton grading system for subglottic stenosis.

Classification of Subglottic Stenosis

Subglottic stenosis can be either congenital or acquired. A diagnosis of congenital stenosis is made when there is absence of any factors that are known to lead to acquired stenosis and there is no previous documentation of a normal airway.

Congenital Subglottic Stenosis

Congenital subglottic stenosis is considered to be the third most common congenital abnormality of the larynx. Its true incidence is not known since some patients diagnosed with acquired stenosis after endotracheal intubation may have had a mild preexisting congenital stenosis.

Acquired Subglottic Stenosis

Acquired subglottic stenosis is much more common than congenital subglottic stenosis and is generally more severe and difficult to manage. The most common cause of acquired subglottic stenosis in children is endotracheal intubation trauma, accounting for approximately 90% of cases, although it can also occur as a result of surgical trauma, inflammation , external trauma, and thermal or chemical burns.

Pathogenesis

Subglottic stenosis secondary to endotracheal intubation is a result of pressure necrosis of the subglottic mucosa. The duration of intubation is the most important factor in the development of subglottic stenosis. Edema and ulceration occur followed by secondary infection and perichondritis. Granulation tissue then forms over the areas of perichondritis and the deposition of fibrous tissue results in stenosis. The role of gastroesophageal reflux in the pathogenesis of subglottic stenosis is not clear yet.

Prevention

The reported incidence of subglottic stenosis in children following endotracheal intubation ranges from 1% to 9%. This rate has fallen because of the introduction of preventive measures by pediatric intensive care units, although the reduction in incidence is somewhat offset by the increased survival of low birth weight infants requiring prolonged intubation. Factors that have reduced the incidence of subglottic stenosis include (1) the use of uncuffed, polyvinylchloride tubes; (2) the use of smaller tubes to reduce pressure on the subglottic mucosa; and (3) nasotracheal intubation, which produces better tube fixation and less frictional trauma.

Clinical Findings

Symptoms and Signs

The degree of stenosis dictates the severity of stridor. Severe congenital subglottic stenosis presents at birth with stridor and respiratory distress. Less severe stenosis is likely to present in the first few months of life when increased activity requires increased respiratory efforts. The subglottic edema produced by upper respiratory tract infections often precipitates stridor, which leads to misdiagnosis of recurrent laryngotracheobronchitis. In the case of acquired subglottic stenosis in neonates, the first indication may be a failed trial of extubation. Older children who sustain subglottic trauma may be successfully extubated, but gradually develop symptoms of respiratory distress over a period of weeks, as the fibrosis progresses.

Evaluation

Lateral neck and chest x-rays may show a stenosis of the airway in the subglottic region; however, confirmation of the diagnosis requires laryngotracheobronchoscopy under general anesthesia. At this point, staging of the stenosis can be performed.

Treatment

The management of subglottic stenosis is dictated by the type of stenosis, the grade of stenosis, and the age and general condition of the patient. Surgical reconstruction is indicated when conservative efforts to establish a satisfactory airway are inappropriate or have failed.

Observation

In patients with minimal symptoms (Grade I or II), it may be possible to avoid surgical intervention with close observation and repeated endoscopies. This conservative approach ensures that the airway is increasing in dimension with the growth of the child.

Tracheotomy

A tracheotomy is frequently performed in patients with symptomatic subglottic stenosis to ensure that the airway is safe until laryngeal reconstruction is planned. It allows time for weight gain and recovery from pulmonary disorders in preterm neonates.

Endoscopic Treatment

Endoscopic use of the laser is useful in the treatment of early intubation injuries, particularly for the removal of granulation tissue and mild stenosis. The disadvantage of laser use is that thermal damage can result in scarring and possible worsening of the stenosis in the long term.

Anterior Cricoid Split

This procedure is used primarily as an alternative to tracheotomy in premature infants with an acquired subglottic stenosis who have failed multiple extubation attempts. By dividing the cricoid cartilage and the first two tracheal rings anteriorly, the cricoid is able to expand, thereby improving the airway.

Laryngotracheal Reconstruction

A variety of surgical techniques aimed at achieving an adequate airway have been described. Following laryngofissure, a cartilage graft can be inserted anteriorly, or both anteriorly and posteriorly. Conventionally, a stent is left in the larynx for a prolonged period until healing occurs; a tracheotomy is also required to maintain airway patency. Once a satisfactory laryngeal airway is achieved, decannulation can be considered. Single-stage laryngotracheal reconstruction has been introduced. Cartilage grafts are inserted, but endotracheal intubation is maintained for 710 days to stent the larynx, and a tracheotomy is not required. This technique avoids the complication of long-term stenting, but there is an increased potential risk to the airway in the perioperative period.

Cricotracheal Resection

In contrast to laryngotracheal reconstruction, which is designed to enlarge the stenosed portion of the larynx, cricotracheal resection excises the stenotic region. This procedure carries a higher rate of success, but a possible favorable outcome must be weighed against the potential complications of recurrent laryngeal nerve damage and dehiscence of the anastomosis.

Cotton RT. Management of subglottic stenosis. Otolaryngol Clin North Am. 2000;33:111. (Detailed review of the management of subglottic stenosis including a discussion on the role of gastroesophageal reflux.) [PMID: 10637347]

Hartley BEJ, Cotton RT. Pediatric airway stenosis: laryngotracheal reconstruction or cricotracheal reconstruction? Clin Otolaryngol Allied Sci. 2000;25:342. (Discussion of surgical procedures for subglottic stenosis with a description of the operative technique for cricotracheal resection.) [PMID: 11012644]

Subglottic Hemangiomas

Essentials of Diagnosis

• Stridor in first 6 months of life.
• Commonly associated with cutaneous hemangioma.
• Progression of symptoms from intermittent to persistent.
• Vascular mass in subglottis.
• Spontaneous resolution over several years.

General Considerations

Hemangiomas can occur in any part of the larynx, but the subglottis is the most common site. Subglottic hemangiomas are typically unilateral, but they can also be circumferential or can arise from multiple sites. They are vascular hamartomas that are most commonly capillary in nature on histologic examination; however, cavernous or mixed types can also occur. Subglottic hemangiomas are rare, accounting for approximately 1.5% of all congenital laryngeal anomalies. Cutaneous hemangiomas , a relatively common congenital abnormality, are found in about half of patients with a subglottic hemangioma and are frequently found in the head and neck region. There is a female preponderance, being twice as common in females.

The natural progression of hemangiomas is from an initial proliferative phase to an involutional phase. The proliferative phase starts soon after birth and usually continues for 12 months, after which gradual involution occurs over a period of years. Most hemangiomas will have resolved by the age of 5 years.

Clinical Findings

Symptoms and Signs

Because hemangiomas do not start to proliferate until after birth, they rarely present in the first weeks of life, but 8090% will have presented by the age of 6 months. Initially, when the lesion is small, inspiratory stridor is intermittently present. At this stage, symptoms may be exacerbated by upper respiratory tract infections, which may lead to an initial diagnosis of recurrent laryngotracheobronchitis. As the lesion enlarges, the stridor becomes biphasic, and dyspnea and cyanosis may occur. The cry is usually normal unless the hemangioma extends onto the vocal folds.

Evaluation

The diagnosis of subglottic hemangioma may be suspected from the clinical presentation and reinforced by the finding of an asymmetric narrowing of the subglottis on lateral neck and chest x-rays. However, confirmation of the diagnosis requires laryngotracheobronchoscopy under general anesthesia. The typical finding on endoscopy is a unilateral, sessile, submucosal, compressible vascular lesion in the subglottis. The role of biopsy for histopathologic confirmation of the diagnosis is controversial , since it carries the risk of significant hemorrhage, although biopsy without associated bleeding is widely reported. Biopsy is generally reserved for those in which the diagnosis is uncertain .

In cases of a large cutaneous hemangioma in the neck associated with a hemangioma of the airway, further investigation with MRI is indicated since the lesions may be contiguous.

Treatment

Observation may be appropriate if the lesion is small and the symptoms are minimal. Most patients require a multimodality treatment. The aims of treatment are to overcome the airway obstruction while avoiding complications and long-term sequelae, particularly subglottic stenosis. A variety of treatment modalities are currently in use.

Tracheotomy

When tracheotomy is used as the sole treatment, decannulation is the ultimate aim. Decannulation can be attempted only when the airway is no longer compromised (as a result of the increased dimensions of the growing larynx and spontaneous involution of the hemangioma). Tracheotomy, however, is not without complications. Subglottic stenosis, in particular, is a recognized complication of tracheotomy and may require surgical intervention before decannulation can be achieved. If the hemangioma is large, there is a risk of complete airway obstruction if the tracheotomy tube becomes dislodged; therefore, skilled home care is required. There is also a significant effect on speech and language development, and multiple endoscopies are required to assess the stage of the airway. In view of these problems, treatment modalities have been developed to either expedite the possibility of decannulation or to avoid tracheotomy altogether.

Steroids

For the treatment of subglottic hemangiomas, steroids can be administered either systemically or by intralesional injection. It is not known how steroids accelerate the involution of hemangiomas, but it may be as a result of estrogen receptor blockade. Systemic steroids need to be used over a prolonged period, which may result in growth retardation, hypertension, and cushingoid appearance. The use of intralesional steroid injection aims to avoid these systemic side effects. However, local edema often results in an initial worsening of the airway, and if tracheotomy is to be avoided, then long-term intubation may be required until resolution of the edema has occurred. Repeated injections may be required before a satisfactory result is achieved.

Laser Therapy

Both the carbon dioxide (CO ₂ ) and potassium titanyl phosphate (KTP) lasers have been used for the treatment of subglottic hemangioma. The advantage of using the laser is its hemostatic properties. This is particularly true of the KTP laser because the wavelength of light is better absorbed by vascular tissue. It may be possible to avoid tracheotomy with repeated laser treatment, but equally repeated treatment increases the risk of scarring and subsequent subglottic stenosis.

Surgical Excision

The surgical excision of subglottic hemangiomas has been reserved for the most severe cases or cases that do not respond to more conventional therapy. However, with the development of the single-stage laryngotracheoplasty in the management of subglottic stenosis, primary excision is likely to become more commonplace as the need for a tracheotomy is avoided.

Interferon

Interferon alfa-2a has antiangiogenic activity and is therefore effective as a treatment for hemangiomas in their proliferative phase. Its use is generally reserved for patients with multiple airway sites or extensive cervical disease with external compression of the airway. The early withdrawal of treatment during the proliferative phase may result in rapid rebound growth; therefore, treatment must be prolonged. Because of the unknown side effects of long-term treatment in children, interferon remains an option only in the most severe unresponsive cases.

Kacker A, April M, Ward RF. Use of potassium titanyl phosphate (KTP) laser in management of subglottic hemangioma. Int J Pediatr Otorhinolaryngol. 2001;59:15. (Discusses the results of KTP laser use for subglottic hemangiomas and compares the relative merits of CO ₂ and KTP lasers.) and KTP lasers.)  [PMID: 11177013]

Rahbar R, Nicollas R, Roger G et al. The biology and management of subglottic hemangioma: past, present, future. Laryngoscope. 2004;114(11):1880. (Review of the natural history and management of the subglottic hemangioma.) [PMID: 15510009]

Sie CY, Tampakopoulou DA. Hemangiomas and vascular malformation of the airway. Otolaryngol Clin North Am. 2000; 33:209. (Review of subglottic hemangiomas and other congenital vascular lesions of the pediatric airway.) [PMID: 10637353]

Respiratory Papillomatosis

Essentials of Diagnosis

• Hoarse voice.
• Gradual onset of stridor.
• Recurrent disease requiring multiple surgical procedures.
• Viral etiology.

General Considerations

Although juvenile-onset recurrent respiratory papillomatosis is a rare disease, it is the most common neoplasm of the larynx in children. Diagnosis is most commonly made between the ages of 2 and 5 years, but papillomas can present in any age group. There is no difference in incidence between males and females. The first-born, vaginally delivered child of a teenage mother is associated with an increased chance of developing respiratory papillomatosis.

Papillomatosis is caused by infection with human papillomavirus (HPV), the most commonly identified subtypes being HPV-6 and HPV-11 (HPV-11 is more aggressive and more prone to malignant changes). The same HPV subtypes are responsible for genital warts, and there is a recognized association between maternal genital warts and respiratory papillomatosis. The precise mode of transmission is not clearly understood, although the aspiration of amniotic fluid during vaginal delivery and viremia leading to hematogenous infection of the fetus are the commonly accepted modes. The larynx is the most commonly affected site in respiratory papillomatosis, particularly the glottis and the anterior commissure, but the mouth, the pharynx, the tracheobronchial tree, and the esophagus can all be affected. Pulmonary papillomatosis is rare but carries high morbidity and mortality. The malignant transformation from benign nonkeratinizing squamous papillomas to squamous cell carcinoma can occur in children, but is rarely seen. Malignant transformation most commonly occurs in the distal bronchopulmonary tree, and the prognosis is universally poor.

Juvenile-onset respiratory papillomatosis has a more severe clinical course than that of adult-onset papillomatosis. Characteristically, multiple foci of papilloma recur frequently after treatment and usually require multiple surgical interventions. Spontaneous remission does occur but is unpredictable, and recurrence has been reported after prolonged disease-free periods.

Clinical Findings

Symptoms and Signs

Hoarseness, abnormal cry, or both are the most common presenting symptoms of respiratory papillomatosis. If the disease is untreated, then a gradual progression to dyspnea, stridor, and eventually, complete airway obstruction can occur. Stridor and airway obstruction are rarely the first symptoms. Examination may reveal a papilloma in the mouth or pharynx, although this finding is unusual. In a cooperative child, the diagnosis can be made by inspecting the larynx with either a laryngeal mirror or a flexible fiberoptic endoscope.

Evaluation

If the diagnosis of respiratory papillomatosis is suspected, then a histopathologic confirmation is required. At microlaryngoscopy, the papillomas are seen to be firm, irregular, exophytic lesions that bleed easily on manipulation. Examination should include tracheobronchoscopy to determine whether distal spread has occurred.

Treatment

The primary treatment modality for respiratory papillomatosis is surgery. The aims of treatment are to maintain an adequate airway while avoiding tracheotomy, preserving the voice, and controlling the papilloma. The most widely accepted means of surgical ablation of respiratory papilloma is with the CO ₂ laser. Because respiratory papillomatosis typically requires multiple procedures to maintain the airway, there is a significant risk of scarring and web formation due to repeated thermal damage caused by the laser. For this reason, it is advisable to leave small amounts of the papilloma in sites where scarring is likely to occur, such as the anterior commissure. Other disadvantages of using the laser include destruction of the papilloma, which both precludes histologic examination and exposes the operating room staff to virus particles in the laser plume. Removal of laryngeal papilloma has been reported using a powered shaver developed for use in the larynx. Although this system reduces the risks associated with the laser, it carries the potential disadvantage of poor hemostatic control. This finding does not appear to be problematic in preliminary reports .

Up to 20% of reported cases of respiratory papillomatosis are severe enough to require tracheotomy, although, if possible, a tracheotomy should be avoided because of the increased risk of distal spread.

Several adjuvant systemic therapies are available. The risks and benefits of adjuvant therapy should be carefully considered before use. Adjuvant therapies in use or under investigation include indole 3-carbinol, di-indolymethane, alfa interferons, acyclovir, photodynamic therapy, ribavirin, retinoic acid, mumps vaccine injections, and cidofovir. There is still insufficient evidence on the effectiveness of antiviral therapy. The ideal dose, frequency, and duration of cidofovir therapy are yet to be known.

Dekay CS. Recurrent respiratory papillomatosis. Laryngoscope. 2001; 111(1):57. (General review of the condition and the practice guidelines.) [PMID: 11192901]

Shehab N, Sweet BV, Hogikyan ND. Cidofovir for the treatment of recurrent respiratory papillomatosis: a review of the literature. Pharmacotherapy. 2005;25(7):977. (Review of the safety and efficacy of cidofovir therapy in respiratory papillomatosis.) [PMID: 16006276]

Inflammatory Causes of Stridor: Introduction

The major causes of inflammatory stridor in children are laryngotracheobronchitis, epiglottitis, and, rarely, bacterial tracheitis. The major features of laryngotracheobronchitis and epiglottitis are compared in Table 323.

Table 323. A Comparison of the Main Features of Epiglottitis and Laryngotracheobronchitis.

	Epiglottitis	Laryngotracheobronchitis
Microbiology	Haemophilus influenzae type b	Parainfluenza virus
Age group	26 years	< 3 years
Onset	Rapid (hours)	Slow (usually days)
Cough	Absent	Barking cough
Dysphagia	Severe	None
Stridor	Inspiratory	Biphasic
Temperature	Elevated	Elevated
Posture	Sitting forward	Lying back
Drooling	Marked	None
Voice	Muffled	Hoarse
X-ray	Thumbprint sign	Steeple sign

Laryngotracheobronchitis (Croup)

Essentials of Diagnosis

• Gradual onset of symptoms.
• Barking cough.
• Stridor.

General Considerations

Laryngotracheobronchitis is the most common infectious cause of airway obstruction in children, usually occurring between the ages of 6 months and 3 years. It is a viral infection most commonly caused by the parainfluenza virus, although numerous other organisms have been reported. Symptoms occur as a result of mucosal edema in the larynx, trachea, and bronchi.

Recurrent episodes of laryngotracheobronchitis should raise the suspicion of underlying abnormalities; therefore, further investigation is indicated.

Clinical Findings

Symptoms and Signs

Characteristically, the symptoms of laryngotracheobronchitis are gradual in onset and are often preceded by an upper respiratory tract infection. A barking cough is invariably present along with hoarseness and stridor. If stridor is present, it is usually inspiratory in nature, and the onset of biphasic stridor and other signs of respiratory distress are indicative of severe airway obstruction. Symptoms typically last between 3 and 5 days, although the child may be infectious for 2 weeks.

Evaluation

Although the diagnosis of laryngotracheobronchitis is mainly based on clinical findings, plain-film x-rays of the neck and chest can be useful. The upper trachea and subglottis may be narrowed (steeple sign) in laryngotracheobronchitis, and other diagnoses, such as foreign body, can be excluded. A blood film reveals a leukocytosis in some cases. If the child has significant symptoms of airway obstruction, then the management should be as described for epiglottitis.

Treatment

Over 85% of cases of laryngotracheobronchitis are mild and can be managed in the community. Parents are typically advised to nurse their child in a humidified room and it seems to be effective anecdotally.

In patients with more severe symptoms, nebulized racemic epinephrine produces a rapid improvement in symptoms by vasoconstriction and reduction in mucosal edema. Heliox has also proved to be beneficial in the acute phase. Both nebulized and systemic steroids have been demonstrated to produce an improvement in the symptoms and the length of time spent in the hospital as well as a decreased need for other interventions such as intubation. Because the beneficial effects of steroids require several hours before onset, the simultaneous administration of racemic epinephrine and steroids results in both immediate and lasting symptom relief. A small number of cases of laryngotracheobronchitis (1.5%) do not respond to medical therapy and airway obstruction worsens. In this situation, endotracheal intubation and ventilation is indicated until the edema resolves.

Supraglottitis (Epiglottitis)

Essentials of Diagnosis

• Rapid progression of symptoms.
• Severe odynophagia with drooling.
• Irritability, fever , toxicity, or any combination of these symptoms.
• Stridor (late sign).

General Considerations

In epiglottitis, or more correctly, supraglottitis , the cellulitis involves multiple areas of the supraglottis. Typically, acute supraglottitis presents in children between the ages of 2 and 6 years, although any age group, including adults, can be affected. Haemophilus influenzae type B (HIB) is the responsible pathogen in most cases, and, as a result of the introduction of the HIB vaccine, the incidence of supraglottitis has been reduced by more than 90%. Although supraglottitis is a rare infection, awareness of the disease is important because of its high mortality rate (if not promptly diagnosed and treated) and the changing trends of the disease in the HIB vaccination era (eg, an increase in the presenting age in children).

Clinical Findings

Symptoms and Signs

Symptoms of acute supraglottitis progress rapidly over a matter of hours. The typical features are fever, difficulty in breathing , and severe odynophagia, which results in drooling. The child is usually irritable sitting or leaning forward, and if the child can speak, the voice is typically muffled. Inspiratory stridor is a late feature occurring when the airway is almost completely obstructed.

Evaluation

Once the diagnosis of supraglottitis is suspected, further investigations should not be undertaken since any procedures that induce anxiety in the patient, including intraoral examination and venipuncture, may precipitate complete airway obstruction. In mild cases without respiratory distress, the most useful diagnostic tool is a lateral neck x-ray, which classically demonstrates a swollen epiglottis (the "thumb print" sign) and can help exclude other diagnoses, such as a foreign body or a retropharyngeal abscess. Also, transnasal flexible fiberoptic laryngoscopy can be judiciously used in the evaluation of the stridulous patients with no respiratory distress, based on the patient's age, condition, and cooperation.

Treatment

The management of a child with suspected supraglottitis requires close cooperation among the otolaryngologist, the anesthesiologist, and the pediatrician. The child should be directly transferred to the operating room where equipment for emergency tracheotomy must be available. After inhalational anesthesia, the supraglottis can be inspected and the presence of erythema and edema confirms the diagnosis. The airway is then secured by endotracheal intubation. Once the airway is safe, blood cultures and swabs of the supraglottis can be obtained and an intravenous cannula inserted. Parenteral antibiotic therapy (eg, ceftriaxone or cefotaxime) should then be started. Supraglottitis usually responds rapidly to treatment and extubation is often possible after 4872 hours.

Bacterial Tracheitis

Bacterial tracheitis is a rare infection that is thought to occur as a secondary bacterial colonization following a viral respiratory tract infection. Involvement of the subglottis and main bronchi is not uncommon. The age at presentation is much more diverse than that seen with croup and has been reported from infancy to adulthood , although the seasonal variation in incidence mirrors that of viral infections of the respiratory tract. The most commonly isolated bacterial pathogen is Staphylococcus aureus.

The initial clinical course of bacterial tracheitis is often similar to that seen with croup and is followed by an acute exacerbation of airway obstruction with associated high fever and toxicity. This rapid onset of symptoms is similar to that of supraglottitis, but drooling and dysphagia are absent.

Plain-film x-rays of the neck may demonstrate narrowing of the tracheal lumen, but endoscopy is required to confirm the diagnosis. The typical appearance is a diffusely ulcerated tracheal mucosa with copious purulent secretions partially obstructing the lumen of the trachea. Specimens should be sent for culture at the time of endoscopy, and the tracheal and bronchial secretions should be suctioned. Most patients require endotracheal intubation and ventilation, which secures the airway and allows repeated tracheal suction. Broad-spectrum parenteral antibiotics should be initiated and adjusted accordingly when the causative organism is identified.

Ausejo Segura M, Saenz A, Pham B et al. Glucocorticoids for croup (Cochrane review). The Cochrane Library. Issue 4, 2001. Oxford: Update Software. (Meta-analysis to determine the effectiveness of glucocorticoids in the management of croup.) [PMID: 10796674]

Shah RK, Roberson DW, Jones DT. Epiglottitis in the Haemophilus influenzae type B vaccine era: changing trends. Laryngoscope. 2004;114(3):557. (A 10-year retrospective study to evaluate the changing trends in the demographics , causative organisms and natural history of epiglottitis after the introduction of the HIB vaccine.) [PMID: 15091234]

Stroud RH, Friedman NR. An update on inflammatory disorders of the pediatric airway: epiglottitis, croup, and tracheitis. Am J Otolaryngol. 2001;22(4):268. (Discusses the pathogenesis, clinical presentation, and management of the common pediatric inflammatory airway diseases.) [PMID: 11464324]

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