Marshall E. Smith
ORAL CAVITY AND OROPHARYNX
EMBRYOLOGY
The oral cavity begins as a depression that invades into the developing embryo. It invaginates until the ectoderm of the stomodeum contacts the endoderm of the primitive foregut, creating the buccopharyngeal membrane. This membrane degenerates at 4 weeks of gestation, providing continuity between the ectodermally derived oral cavity and the endodermally derived oropharynx. The five branchial arches are mesodermal condensations on the lateral cervical area of the embryo and are separated by branchial clefts externally and branchial pouches internally. The cleft is ectodermally lined, whereas the pouch is endodermally lined. The first arch develops into the mandible, the portions of the ossicles, and the muscles associated with these structures. The second arch contributes to portions of the ossicles, the styloid process, the portions of the hyoid bone, the facial muscles, the posterior belly of the digastric muscle, and the buccinator muscles. The third arch differentiates into portions of the hyoid bone and pharyngeal muscles. The fourth arch develops into the anterior/superior portions of the larynx. Finally, the fifth arch contributes to the posterior, larynx, cricoid, and intrinsic muscles of the larynx and the inferior pharyngeal constrictor muscle.
The pharyngeal pouches produce a variety of structures. The first pouch becomes the middle-ear cavity. The first branchial cleft creates the external ear canal. The tonsils are formed from contributions from both the first and second pouches invading into the surrounding mesoderm. Between the third and fifth months of gestation, lymphatic tissue then invades these primitive structures. The third pouch gives rise to the thymus gland and the inferior parathyroid glands. The fourth pouch develops into the thyroid gland and the superior parathyroids.
The hard palate is divided into a primary and secondary palate. The primary palate contains the anterior alveolus and the four upper incisors and is derived from the medial nasal swelling. The secondary palate (the area posterior to the incisive canals) is formed by the medial growth of the lateral palatine processes of the maxilla. The primary palate is completely developed by the seventh week of gestation, and the secondary palate completes its fusion between weeks 10 and 12 of gestation. Clefts of the soft palate are generally associated with clefts of the secondary hard palate. Complete clefts involve the primary, secondary, and soft palate structures.
The anterior two thirds of the tongue are derived from ectoderm, whereas the posterior one third is derived from endoderm of the primitive foregut. Swellings begin to condense during the fourth week of gestation and are complete by the seventh week. The fungiform and filiform papillae develop by the 11th week, and the circumvallate papillae develop between weeks 8 and 20. The floor of the mouth is a first arch derivative. The salivary glands are of ectodermal origin and are derived from the first pouch, developing between weeks 5 and 8.
ANATOMY
Oral Cavity The oral cavity is surrounded anteriorly by the lips. The lips are supplied with a rich sensory innervation and fine-motor control to provide a complex sphincter mechanism. The lips function to prevent the loss of saliva and food materials from the oral cavity and are instrumental in producing labiodental and plosive speech sounds. Loss of sensation interferes with the protective function of the labial sphincter, often causing sialorrhea and mild feeding problems. The dental arches support the teeth and gingival mucosa, which cover the alveolar ridges. The lingual frenulum divides the floor of the mouth in the midline. The geniohyoid, mylohyoid, genioglossus, and hyoglossus muscles support the floor of the mouth.
The Tongue The tongue is an important structure for communication and mastication. Fine-motor abilities of the tongue permit proper articulation for speech and provide the necessary manipulation of food materials. The tongue is divided into an anterior two thirds (which lie within the oral cavity) and a posterior one third (which lies within the oropharynx). The division between these two areas is demarcated by the large circumvallate papillae that form a V, with the apex posteriorly at the foramen cecum. The foramen cecum is an embryologic derivative of the thyroid gland. If the thyroid gland fails to descend, a lingual thyroid may be visible on the dorsum of the tongue in this area. The tongue’s mucosal covering is composed of a mixture of papillae. In addition to the circumvallate papillae, smaller fungiform papillae are located on the lateral aspects and on the tip of the tongue. The filiform papillae are the most abundant and cover the dorsum of the tongue. Taste buds are abundant on the circumvallate and fungiform papillae. The filiform papillae contain no taste buds.
The tongue’s musculature is composed of intrinsic and extrinsic muscle groups. The extrinsic muscles include the genioglossus, the hyoglossus, and the styloglossus. These muscles assist in positioning the tongue forward, backward, upward, and downward. The intrinsic muscles of the tongue—the transverse, vertical, and longitudinal muscles—are responsible for changing the tongue’s shape and are integral to both speech and swallowing. Sensation is supplied to the anterior two thirds of the tongue via the lingual nerve, which is a branch of the mandibular division of the trigeminal nerve. The posterior one third of the tongue is innervated by the glossopharyngeal nerve. Special taste afferents from the anterior tongue course through the lingual nerve to the chorda tympani nerve within the middle ear. The hypoglossal nerve controls the tongue’s motor function. Injury to this nerve will result in a tongue that deviates to the injured side on protrusion.
Palate, Velopharyngeal Sphincter, and Pharynx The palate comprises the roof of the mouth. The bony hard palate is in continuity with the soft palate posteriorly. The hard palate consists of three fused bones. The soft palate consists of muscles that originate from the posterior edge of the hard palate and the skull base. Sensory innervation to the palate is supplied by branches of the maxillary division of the trigeminal nerve, whereas motor innervation is supplied through the pharyngeal plexus of the vagus nerve. Only the tensor veli palatini muscle receives innervation from the motor division of the trigeminal nerve. The six muscles of the soft palate (levator veli palatini, tensor veli palatini, musculus uvulae, palatoglossus, palatopharyngeus, and superior pharyngeal constrictor) act to create a dynamic sling. The coordinated movement of these muscles closes the velopharyngeal sphincter, which separates the nasopharynx from the oropharynx during swallowing and speech.
In addition to assisting palate elevation, the tensor veli palatini is the primary muscle responsible for opening the eustachian tube. Abnormalities in the orientation of this muscle or its insertion in the eustachian tube cartilage, such as seen in cleft palate, greatly predispose individuals to chronic ear disease. The pharynx is a mucosal-lined tube that extends from the skull base to the esophageal inlet. It is divided into three parts—the nasopharynx, the oropharynx, and the hypopharynx. The nasopharynx is located superiorly and extends from the posterior choanae of the nasal cavity anteriorly to the level of the free edge of the soft palate inferiorly. It contains the eustachian tube and the adenoid. The oropharynx extends from the free margin of the soft palate to the vallecula. The vallecula is the space created by the junction of the tongue base with the epiglottis. The faucial tonsils lie within the oral cavity. Anteriorly, the oropharynx extends to the anterior tonsillar pillars. The hypopharynx extends from the vallecula to the esophageal inlet. The larynx and pyriform sinuses are contained within the hypopharynx.
The pharyngeal constrictors are paired muscles lining the pharynx. They insert into the medial raphe on the midline of the posterior pharyngeal wall. The superior, middle, and inferior pharyngeal constrictors are responsible for the forces generated to clear materials from the pharynx during the act of swallowing. The innervation of all the pharyngeal muscles is from the pharyngeal plexus of the vagus nerve, except the stylopharyngeus muscle, which is innervated by the glossopharyngeal nerve. Sensory innervation to the pharynx is via the glossopharyngeal nerve and pharyngeal plexus inferiorly and the maxillary division of the trigeminal nerve superiorly.
Salivary Glands The parotid duct (Stensen duct) enters the oral cavity through the buccal mucosa, which is adjacent to the second maxillary molar at the level of the gingival mucosa. The sublingual glands and the duct from the submandibular gland (Wharton duct) enter the floor of the mouth on either side of the lingual frenulum. The paired parotid glands produce the majority of the serous secretions in the mouth. The submandibular and sublingual glands predominately produce mucoid secretions in response to gustatory stimuli. Secretions in the mouth that are formed during times other than eating are expressed by minor salivary glands scattered throughout the mucosa lining the oral cavity and the pharynx.
Tonsils and Adenoids The tonsils lie within the oropharynx. The palatine or faucial tonsils are paired collections of lymphoid tissue. The tonsils are bounded anteriorly by the palatoglossus muscle (anterior tonsillar pillar) and the palatopharyngeus muscle (posterior tonsillar pillar). The superior pharyngeal constrictor muscle is deep to the tonsil. The pharyngeal tonsil—or adenoid—resides in the nasopharynx. The lingual tonsil resides in the base of the tongue. Superficial bands of lymphoid tissue connect these four masses of tonsil tissue. Waldeyer’s ring refers to this encircling mass of lymphoid (tonsillar) tissue. Its function is to process antigens and present them to the germinal centers of the lymphoid follicles. This modulates both Band T-cell populations within the tonsil in early childhood. As people age, the tonsil and adenoid tissue atrophies.
EVALUATION OF THE ORAL CAVITY AND PHARYNX
Physical Examination
The oral examination begins anteriorly with a systematic evaluation of structures from anterior to posterior and from left to right. The floor of the mouth is examined by having the patient elevate the tongue. In small children, the tongue will often need to be elevated mechanically. The tonsils should be evaluated for signs of inflammatory changes and for debris collecting within the crypts of the tonsil. Tonsillar size should be graded on a scale of 1 to 4 (Fig. 371-1). The oropharyngeal inlet should also be evaluated for adequacy. The tonsils may be of relatively small size but when combined with a small oropharyngeal inlet, may be obstructing. The posterior pharyngeal wall should be checked for symmetry. Granular tissue may often be seen on the posterior pharyngeal wall and may represent small areas of lymphoid tissue.
Figure 371-1. Grading of tonsillar size. (1) Tonsils are contained within the tonsillar fossa; (2) tonsils extend to the medial extend of the tonsillar pillars; (3) tonsils extend beyond the tonsillar pillars; (4) tonsils touch in the midline.
The soft palate should be evaluated both at rest and in motion. The uvula deserves close attention. A bifid uvula may be a sign of a submucosal cleft of the palate. On phonation, the soft palate should elevate and its motion should be symmetric. Intraoral palpation may also be warranted (a gloved index finger). The floor of the mouth can be palpated to check for signs of a mass or stone development within salivary ducts. The hard palate can be palpated, paying attention to the feel of its posterior aspect. A posterior projection should be apparent, signifying normal anatomy. Notching of the posterior aspect of the hard palate is found in submucous cleft palate. The buccal area can also be palpated, feeling for stones and expressing saliva from the parotid glands. The tongue can be palpated to feel for abnormalities within the substance of the tongue.
Flexible fiberoptic endoscopy of the pharynx and upper airway is an extremely useful procedure. It can be easily and safely performed in an otolaryngologist’s office in children of all ages without sedation, using only a topical anesthetic. The endoscopy checks the following: the nasopharynx for nasopharyngeal obstruction due to adenoid hypertrophy or other mass lesion and adequacy of velopharyngeal closure; the soft palate for the presence of a submucosal cleft; the tongue base, palatine, and lingual tonsils for size and inflammatory changes; and the hypopharynx and larynx for signs of obstruction from cysts, masses, or inflammation.
Radiological evaluation may be done when endoscopic examination is not available or to supplement its findings. It can begin with a lateral neck x-ray, which provides good visualization of the nasopharynx and assesses the overall size of the adenoid pad. Retropharyngeal and inflammatory processes on the posterior pharyngeal wall may also be identified. Computed tomography with contrast is now the generally accepted method for evaluating suspected inflammatory or neoplastic lesions of the pharynx. This may be supplemented by magnetic resonance imaging to provide fine detail of specific abnormalities in the oral cavity and oropharynx and the relationship to surrounding structures.
APPROACH TO THE CHILD WITH EXCESSIVE SIALORRHEA
Excessive sialorrhea, or drooling, is an uncommon problem in children who do not have developmental delay. Although some children will demonstrate significant sialorrhea early in life, this almost always self-corrects as the child reaches the fourth year of life. However, for the occasional child in whom this does not resolve or in children who have neurodevelopmental delays, a thorough workup should be done. This is best accomplished by a multidisciplinary team that includes an otolaryngologist; a dentist; and a pediatric specialist who has particular interest in childhood development, special needs children, rehabilitation, and neurological development. The otolaryngologist and dental team should perform a complete head and neck exam to ensure there are no anatomic causes for the excessive sialorrhea or other associated abnormalities in the oral cavity and pharynx, such as sensory defects or swallowing dysfunction. In children without previously diagnosed developmental delays, a full workup to rule out any undiagnosed condition should be considered. In children without a defined anatomical, motor, sensory, or neurological difficulty, assistance from a feeding team or swallowing therapist is likely all that will be required to assist with resolving the problem.
In children with neurodevelopmental delays, more aggressive therapy may also be required. This includes pharmacological therapy such as anticholinergic medications and procedural intervention, including botulinum toxin injection, which generally provides transient reduction in salivary production but is relatively noninvasive; salivary duct ligation; and salivary gland excision. The latter two procedures are more permanent but are more invasive. Utilizing these measures, sometimes in conjunction with each other, generally provides relief from excessive sialorrhea even in children with minimal ability to swallow their own secretions.
CONGENITAL MALFORMATIONS
CLEFT LIP AND PALATE
Orofacial clefting is the second most common birth defect, occurring in 1 out of every 750 live births. A cleft lip results from incomplete fusion of embryonic structures surrounding the primitive oral cavity. The clefts may be unilateral or bilateral. They are often associated with clefts of the palate. Clefts of the palate vary greatly in their extent; they may involve only the soft palate or may extend into the hard palate. The cleft may extend through the hard palate and the alveolar ridge and may be in continuity with a cleft of the lip. A combination of cleft lip and palate leads to significant cosmetic deformities of the nose. The structural support of the nose is absent, leading to abnormal lower lateral cartilage development and abnormal nasal septum development. Dental abnormalities are also common. For further discussion of managing cleft palate, see Chapter 177.
A submucous cleft palate may not be recognized until the child is several years of age. The muscular development of the soft palate is similar to that seen in a child with a cleft palate. The levator muscles do not attach in the midline of the soft palate but insert in the posterior edge of the hard palate. Mucosa completely covers the underlying defect so that there is no obvious defect of the soft palate. However, palpation of the posterior edge of the hard palate will frequently demonstrate a notch. Close inspection of the uvula will often reveal a bifid uvular structure. A blue line (zona pellucida) may be seen in the midline of the soft palate because of the lack of musculature in that area. Velopharyngeal insufficiency with hypernasal speech and an increased incidence of otitis media often result from this deformity, which can be surgically repaired if symptoms are significant.
OTHER CONGENITAL ABNORMALITIES
Variations of the dentition and oropharyngeal mucosal lining are discussed in Chapter 378.
Lingual Ankyloglossia
This abnormality is a common disorder and is also known as tongue-tie; with this condition, the lingual frenulum limits the movement of the anterior tongue tip. On protrusion of the tongue, there is frequently a heart-shaped deformity that is created as a very short lingual frenulum tethers the midline of the tongue. The tongue often has difficulty protruding beyond the alveolar ridge. Infants may have trouble attaching to the breast during breast-feeding or to the nipple of a bottle. In some cases, frenuloplasty can aid in tongue protrusion and can facilitate feeding. Speech difficulties secondary to ankyloglossia are uncommon. In the English language, the tongue needs only to touch the upper teeth. There are some social activities that may lead a patient to get a frenuloplasty, such as the inability to lick an ice-cream cone. If the individual is unable to protrude the tongue, this activity can be awkward.
Lingual Thyroid
Failure of the thyroid tissue to descend into the neck from its site of origin in the tongue base results in a raised, violaceous mass at the base of the tongue. In general, this thyroid tissue does not function normally. The size of the mass tends to increase over time. Frequently, signs of airway obstruction will lead the patient to a physician for evaluation. Thyroid hormone replacement will generally reduce the size of the abnormal thyroid remnant. Patients often need long-term thyroid hormone replacement therapy. This is a very rare condition and occurs more commonly in girls.
Thyroglossal Duct Cysts
In rare instances, when the thyroid gland descends into the neck from the tongue, a tract can remain that develops into a midline cystic mass in the neck. Further discussion of presentation and treatment is discussed in Chapter 372.
INFLAMMATORY DISORDERS OF THE TONSILS AND PHARYNX
TONSILLITIS AND PHARYNGITIS
Pharyngitis presents with symptoms of sore throat, pain on swallowing, mild fever, and malaise. The pharynx and tonsils are usually erythematous on examination, and an exudate may be present over enlarged tonsils. Many, slightly enlarged cervical lymph nodes (shotty adenopathy) are often present. Common bacterial pathogens causing tonsillitis and pharyngitis are β-hemolytic Streptococcus, Streptococcus pneumoniae, Hemophilus influenzae, Peptostreptococcus, and Diphtheroids. The symptoms of bacterial pharyngitis are identical to infections caused by viruses. There are no reliable clinical findings that permit the differentiation of viral from bacterial pharyngitis. Throat cultures are necessary to direct treatment (see Chapter 285). Infectious mononucleosis must always be considered in cases of exudative tonsillitis with marked lymph node involvement in the posterior cervical chain. The diagnosis of mononucleosis is made by serology. The tonsils can enlarge enough to obstruct the airway.
Most episodes of pharyngitis and/or tonsillitis resolve without complications. In cases of recurrent acute tonsillitis, or chronic tonsillitis trials of antistaphylococcal antibiotic or rifampin may be helpful in eradicating Staphylococcus aureus or β-hemolytic Streptococcus carriage. When there are multiple episodes of acute tonsillitis, or in chronic tonsillitis unresponsive to medical therapy, adenotonsillectomy may be indicated.
PERITONSILLAR ABSCESS
Infections of the tonsils invade the substance of the tonsillar tissue. Spread of the infection to the surrounding tissue results in a peritonsillar cellulitis that may require intravenous antibiotics to resolve the infection. At times, the cellulitis progresses and a coalescence of the infection leads to development of a peritonsillar abscess. The abscess collection and surrounding soft tissue edema cause medial displacement of the tonsil and asymmetry of the posterior soft palate, with the uvula deviating away from the site of infection and with a downward bulge of the soft palate. Trismus and ipsilateral otalgia may be associated with a peritonsillar abscess. A characteristic muffled (hot potato) voice is heard. Treatment of a peritonsillar abscess generally requires drainage of the abscess. This may be accomplished by needle aspiration, by incision and drainage, or by tonsillectomy. A delayed tonsillectomy is generally recommended in patients with a peritonsillar cellulitis/abscess if there is a preceding history of recurring throat or tonsil infections. Mononucleosis can be associated with coincident peritonsillar abscess.
RETROPHARYNGEAL ABCESS
Lymph nodes in the retropharynx and parapharyngeal space enlarge in response to infection. At times, the node becomes overwhelmed with the infection and becomes necrotic. Cellulitis may progress to abscess. Surgical drainage of the abscess in the retropharyngeal or parapharyngeal space is generally required. Cellulitis will typically respond to high doses of intravenous antibiotics. Peritonsillar abscess, parapharyngeal space abscess, and retropharyngeal abscess all have the potential to cause life-threatening complications if diagnosis and treatment are delayed. A mass effect can cause airway obstruction. Infection may also spread along natural tissue planes upward to the skull base (causing meningitis) or inferiorly into the mediastinum. In cases in which surgical drainage is required, intubation must be performed carefully because the act of intubation can rupture the abscess cavity, soiling an unprotected airway with purulent material.
ADENOTONSILLAR HYPERTROPHY WITH AIRWAY OBSTRUCTION
Adenotonsillar hypertrophy can cause obstruction of the upper airway. Children often present with chronic snoring, interruption of airflow during inspiration, restless sleep behavior, and daytime somnolence. The work of breathing increases as airway obstruction increases. Respiratory rate irregularity also increases as the work of breathing increases. This pattern of sleep disturbance can vary during the night with sleep stages and is often worse during rapid eye movement (REM) sleep. The evaluation and causes of sleep disordered breathing are also discussed in Chapter 509. Snoring is the hallmark of upper airway obstruction and may be caused by enlarged adenoid tissue or tonsils or both. When a questionable history of nighttime breathing patterns is obtained, it is often useful to have the parents record sound alone or videotape the child while sleeping to more adequately allow the physician to evaluate reports of noisy breathing, apneic episodes, and irregular breathing patterns.
Obesity is not always a common feature of children with obstructive apnea. Many children present with poor weight gain because of poor eating habits. Sleep apnea in children is associated with daytime behavioral habits that range from agitation to somnolence. In severely affected children, pulmonary hypertension and cor pulmonale may develop, but these are uncommon. If large tonsils are evident on physical examination, adenotonsillectomy is usually curative. If the tonsils are small on examination, a lateral neck radiograph may demonstrate adenoid hypertrophy or the adenoids can be visualized by nasopharyngoscopy.
Tonsillectomy and Adenoidectomy
The indications for tonsillectomy and adenoidectomy and for adenoidectomy alone are listed in Table 371-1. Rare disorders that appear to improve following tonsillectomy include an immunoglobulin A nephropathy that is associated with recurrent tonsillitis1, and periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome (PFAPA). Surgery is best performed when the acute inflammatory response has subsided, generally 6 weeks after the last infection. In some circumstances, however, a tonsillectomy is necessary during an acute infection if there are life-threatening complications such as airway compromise or development of a peritonsillar abscess. Tonsil-lectomy usually consists of a subcapsular dissection and total removal of the tonsils. When tonsillectomy is performed for sleep-disordered breathing, a partial or intracapsular tonsillectomy is an option for treatment of tonsillar hypertrophy that may be as effective and appears to reduce postoperative pain and decrease recovery time. The most common complication of tonsillectomy is bleeding, occurring in about 3% of children. It most often occurs within 24 hours of surgery but late bleeding occurs up to 10 days following surgery. Other early complications include pain, dehydration and weight loss due to poor oral intake, and occasional difficulty breathing due to swelling around the surgical sites.
Table 371-1. Indications for Tonsillectomy and Adenoidectomy and for Adenoidectomy Alone
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Indications for Tonsillectomy and Adenoidectomy |
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Infectious Disease |
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Recurrent, acute tonsillitis, with more than 6–7 episodes in 1 year, 5 episodes per year for 2 years, or 3 episodes per year for 3 years |
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Recurrent, acute tonsillitis, with recurrent febrile seizures, or cardiac valvular disease |
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Chronic tonsillitis, unresponsive to medical therapy or local measures |
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Peritonsillar abscess with history of tonsillar infections |
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Obstructive Disease |
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Heroic snoring with chronic mouth breathing |
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Obstructive sleep apnea or sleep disturbances |
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Adenotonsillar hypertrophy with dysphagia or speech abnormalities |
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Adenotonsillar hypertrophy with craniofacial growth or occlusive abnormalities |
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Mononucleosis with obstructive tonsillar hypertrophy, unresponsive to steroids |
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Other |
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Asymmetric growth or tonsillar lesion suspicious for neoplasm (without adenoidectomy) |
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Indications for Adenoidectomy Alone |
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Infectious Disease |
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Adenoid hypertrophy with eustachian tube dysfunction and persistent ear infection or middle ear effusion |
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Adenoid hypertrophy associated with chronic sinusitis, unresponsive to medical therapy |
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Obstructive adenoid hypertrophy |
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Heroic snoring with chronic mouth breathing |
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Obstructive sleep apnea or sleep disturbances |
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Craniofacial growth or occlusive abnormalities |
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Other |
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Adenoid mass or lesion or asymmetric enlargement |
TUMORS OF THE OROPHARYNX
The most common benign salivary gland tumor is a mixed or pleomorphic adenoma. This generally develops within the parotid gland but can present as a mass extending from any salivary gland. Mucoepidermoid carcinoma is the most common salivary gland malignancy during childhood, usually originating in the sublingual glands. These lesions are treated by surgical excision.
Other malignant neoplasms that may involve the head and neck include rhabdomyosarcomas, Langerhans histiocytosis, and lymphoma. Extra-nodal tissue involvement is common in non-Hodgkin lymphomas, with approximately 25% originating in extranodal sites and one third of these involving structures in the head and neck. Therefore, asymmetric progressive enlargement of the tonsils or adenoids should raise suspicion of a non-Hodgkin lymphoma, and tonsillectomy should be performed as a biopsy procedure. Similarly, asymmetric enlargement of the tonsils or adenoids may be caused by lymphoproliferative disease in immunosuppressed patients following solid organ transplantation.
PHARYNGEAL TRAUMA
The approach to oral soft tissue and tooth injuries is discussed in Chapter 375. Pharyngeal trauma most commonly results from a child falling while an object is in his or her mouth. These objects will often impale the roof of the mouth and the posterior pharyngeal wall. Families need to be instructed to immediately seek medical attention should any alterations in mental status develop following this type of injury. The internal carotid artery is adjacent to the tonsillar bed; therefore, a puncture injury at this site has the potential for devastating vascular and neurological sequelae. If a Horner syndrome is identified at the time of initial evaluation, carotid injury should be suspected. In rare cases, the carotid intima may be injured, and delayed embolic events (up to 3 days following the injury) with stroke may occur.
Computerized tomography with angiography (CT angio) is generally the radiographic study of choice for this injury but is generally warranted only when there is a high suspicion of carotid artery injury. Lacerations of the soft palate may not require repair. However, large lacerations that extend into the nasopharynx are usually repaired to prevent a palatal fistula.2–5
THE LARYNX
THE NORMAL LARYNX
The larynx is a complex evolutionary structure that joins the trachea and the bronchi to the pharynx as a common aerodigestive pathway. The larynx serves the essential functions of (1) ventilation of the lungs, (2) protection of the lungs during deglutition by its sphincteric mechanisms, (3) clearance of secretions by a vigorous cough, and (4) vocalization. An infant’s survival is predicated on the structural and neurological integrity of the larynx, and prompt diagnostic and surgical intervention for airway management is mandatory.
The larynx is arbitrarily divided into three regions: supraglottis, glottis, and subglottis. The supraglottic larynx is composed of the epiglottis, aryepiglottic folds, arytenoid cartilages, vestibular folds (false vocal folds), and laryngeal ventricles. The glottis comprises the vocal folds, or “vocal cords.” The subglottic region extends from the undersurface of the vocal folds to the base of the cricoid cartilage and represents the smallest diameter of the infant larynx. When an infant is born, the larynx is approximately one third the size of the adult larynx. The vocal folds are 6 to 8 mm long, with the posterior aspect composed of the cartilaginous process of the arytenoid. The subglottic diameter measures approximately 4.5 by 7 mm. A diameter of less than 3.5 mm is suggestive of a subglottic stenosis.
In the infant, the superior border of the larynx is located as high as the first cervical vertebra (see Fig. 371-2). This superior location of the larynx elevates the epiglottis approximately to the level of the palate and helps to explain obligate nasal breathing over the first few months of life. An intranarial larynx creates a partially separate respiratory and digestive tract that mimics lower animal forms. This position is further enhanced in nursing, as forward thrust of the tongue causes increased elevation of the larynx. The child’s and adolescent’s larynx gradually lowers into the neck and enlarges this supralaryngeal region of the pharynx to better accommodate the varied sounds of human speech. The descent of the larynx and elongation of the vocal tract has yielded a trade-off between the advantages of speech production and an increased risk of aspiration. This is most evident in infants and toddlers. Ultimately, in humans, the vocal folds have evolved the highest degree of versatility for voice production by their ability to adjust length, tension, and shape.
Figure 371-2. A: The infant oropharynx. The larynx is elevated, with the epiglottis touching the soft palate. This creates a functional separation between the air passages (white arrow) and the food passages (black/gray arrow) in the pharynx. Food courses around the epiglottis, into the pharyngeal recess, and then to the esophagus. B: The toddler (2–3 years old) oropharynx. C: The adult oropharynx: (a) the oral preparatory phase, (b) the oral phase, (c) the pharyngeal phase, and (d) the esophageal phase. Note that the infant oral cavity is much smaller than the child or adult oral cavity, providing little space for manipulation of the food bolus. The larynx is elevated so that the epiglottis almost touches the soft palate, and the larynx is at the level of the first to third cervical vertebrae. The tongue is entirely within the oral cavity, with no oral region of the pharynx. In the toddler, the larynx descends to the fifth cervical vertebra, and by adulthood it descends to the sixth to seventh cervical vertebra.
APPROACH TO THE CHILD WITH AIRWAY OBSTRUCTION
Evaluating the child with airway obstruction requires a careful history, physical examination, and knowledge of the functional anatomy of the upper airway. Important points in the history and physical are summarized in Table 371-2. Age of onset and duration of stridor are important indicators as to which of the congenital causes of the condition is most likely. A history of intubation may indicate subglottic stenosis. Laryngomalacia is the most common cause of congenital stridor and has a characteristic history of the child breathing more comfortably when relaxed and being more stridorous when agitated. Birth injury or neurological abnormalities may indicate vocal fold paralysis. Acute stridor in the older child may be caused by a foreign body or acute infection.
Symptoms vary depending on the site of obstruction, as outlined in Table 371-3. Although stridor, a high-pitched noise with respiration, is the most common sound exhibited by children with airway obstruction, this first should be differentiated from stertor. Stertor is a lower-pitched nose that originates from the nasal cavity or nasopharynx and is associated with obstruction at these sites. Pathology such as adenoid hypertrophy, choanal atresia, nasal polyps, turbinate hypertrophy, or other nasal masses are associated with stertor. An algorithm for evaluating a child with airway obstruction and stridor is shown in Figure 371-3, and causes of airway obstruction are listed in Table 371-4.
CLINICAL EVALUATION
Careful inspection of the patient is the first priority in any infant with difficulty breathing. The child should remain in the parent’s arms, and the physician can judge the respiratory rate and degree of distress. The physician should look for tachypnea or the onset of fatigue, which may portend respiratory collapse. Flaring of the nasal alae and using accessory neck or chest muscles indicate that an increased degree of respiratory effort is needed to maintain an oxygenated state. Cyanosis and air hunger, particularly from supraglottic infection or from a foreign body, will cause the patient to sit with the neck hyperextended in an attempt to improve airflow. The patient should be permitted to maintain such a posture. In a gravely ill child, additional examination should not be undertaken lest it precipitate respiratory arrest. The child requires prompt transport to an appropriate hospital.
In a well-oxygenated, stable child, additional examination can proceed. An important part of the assessment is auscultation that is performed both with the ear and with the stethoscope. Sequential listening over the nose, open mouth, neck, and chest can localize the probable site of obstruction, which is indicated by a heightened sound intensity. Attention is next directed to the respiratory cycle, which normally is composed of a shorter inspiratory phase and a longer expiratory phase. Laryngeal obstruction is usually associated with inspiratory noises, whereas bronchial obstruction has characteristic expiratory noises or wheezes. Similarly, in laryngeal obstruction, the time of inspiration is lengthened, whereas in bronchial obstruction, expiration tends to be prolonged. Subglottic and tracheal obstruction will often cause both inspiratory and expiratory stridor.
Table 371-2. History and Physical Examination for Airway Obstruction
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History |
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Time of onset: gradual, progressive, or sudden |
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Characteristics of cry |
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Relationship of stridor to feeding |
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Aspiration or reflux |
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Cyanosis |
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Previous intubation |
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Careful, repeated questioning for possible foreign body aspiration |
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Physical Examination |
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Stridor, pitch, duration, and timing of the stridorous sound |
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Careful inspection of the patient in the parent’s arms |
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Respiratory rate and degree of distress |
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Tachypnea and onset of fatigue |
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Flaring of nasal alae and other signs of respiratory effort |
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Ausculatation of stridor |
Table 371-3. Symptoms and the Site of Airway Obstruction
In addition, the infant should be placed in various positions to determine the effect on the stridor. The stridors of laryngomalacia, micro-gnathia, macroglossia, and vascular compression diminish when the baby lies prone with the neck extended. The presence and quality of the voice or cry can help to identify laryngeal causes of stridor. A weak cry suggests causes related to the vocal fold or indicates conditions with poor pulmonary function. Although laryngeal lesions are most often accompanied by voice changes, a normal voice does not rule out a laryngeal cause for stridor. For example, with bilateral vocal cord paralysis, there may be a normal voice but marked airway obstruction.
Figure 371-3. Algorithm for evaluating the child with stridor. Fiberoptic laryngoscopy is performed in the awake child and provides information about vocal fold mobility and laryngeal dynamics. It provides only limited information about structural defects below the level of the vocal cords. Rigid endoscopy using Hopkins rod lens telescopes allows detailed examination of the subglottis, trachea, and bronchi while maintaining a stable airway. The combination of fiberoptic and rigid endoscopy will accurately diagnose most congenital and acquired abnormalities of the airway in children.
Table 371-4. Causes of Airway Obstruction in Children
|
Nasopharynx (Generally Stertor Rather Than Stridor) |
|
Adenoid hypertrophy |
|
Choanal atresia |
|
Encephalocele |
|
Nasal dermoid |
|
Nasal polyps |
|
Oropharynx |
|
Abscess (parapharyngeal, retropharyngeal, peritonsillar) |
|
Craniofacial anomalies (Apert syndrome, Down syndrome, Robin syndrome) |
|
Cysts (branchial, thyroglossal) |
|
Foreign body |
|
Inflammatory |
|
Lingual thyroid |
|
Neoplasm (benign and malignant) |
|
Tonsillar hypertrophy |
|
Larynx |
|
Foreign body |
|
Inflammatory |
|
Croup (bacterial and viral) |
|
Epiglottitis (rare since availability of Haemophilus influenzae B vaccine) |
|
Miscellaneous; tuberculosis, diphtheria |
|
Laryngeal web |
|
Laryngocele |
|
Laryngomalacia |
|
Laryngospasm (extraesophageal reflux) |
|
Neoplasm |
|
Laryngeal papilloma |
|
Malignant (rhabdomyosarcoma, chondrosarcoma) |
|
Vascular anomalies (lymphatic, hemangioma, venous) |
|
Posterior laryngeal cleft |
|
Trauma |
|
Intubation (laryngeal or subglottic edema, subglottic stenosis) |
|
External neck trauma |
|
Subglottic cyst (prominent after intubation) |
|
Subglottic stenosis |
|
Vocal fold paralysis |
|
Trachea and Bronchi |
|
Complete tracheal rings (more prominent in Trisomy 21) |
|
Compression by neoplasm of adjacent structur (thyroid, thymus, esophagus) |
|
Foreign body (tracheal or esophageal) |
|
Tracheal stenosis (congenital or secondary to intubation or tracheostomy) |
|
Trauma |
|
Vascular anomalies (rings and slings) |
Certain maneuvers can be performed to determine the nature of the obstruction. If stridor is present at birth, the first maneuver should be to open the mouth and pull the mandible and tongue forward. If the stridor lessens, the obstruction is at the level of the larynx or higher. Nasal catheters should be passed to determine the patency of the nasopharyngeal airway. In patients with choanal atresia, the placement of an oral airway will help to diagnose the disorder and to bypass the obstruction. Introducing a blade laryngoscope will lift the laryngeal structures and decrease the stridor of laryngomalacia but will not relieve the obstruction of vocal cord paralysis or subglottic stenosis. Pulling the mandible and tongue forward will often relieve the obstruction seen in the Pierre-Robin sequence and other conditions associated with mandibular hypoplasia, and emergency placement of a nasopharyngeal airway will maintain the patient until a long-term care decision can be made.
DIAGNOSTIC TESTS
Diagnostic testing of the infant with stridor always begins with flexible fiberoptic nasopharyngoscopy while awake; this is the most useful and comprehensive of all diagnostic tools available. This test should be performed in all patients with suspected airway pathology. It can be done in even the smallest child and can usually be performed in an office or clinic setting. Vocal fold mobility, laryngeal masses, laryngomalacia, and other laryngeal problems are easily assessed. The examination begins in the anterior nasal cavity to rule out a pyriform aperture stenosis and moves posteriorly in the nose to rule out a choanal stenosis or atresia. The nasopharynx can be examined for adenoid hypertrophy or other mass lesions. Hypopharyngeal visualization will assess the hypopharyngeal tone. The epiglottis and arytenoid cartilages can be evaluated for edema or erythema consistent with reflux esophagitis or infection. In addition, any evidence of laryngomalacia will be noted. Determining the mobility of the true vocal folds is an essential part of this evaluation. A subglottic view is possible with a flexible scope in most cases, but subglottic and distal airway evaluation with endoscopy is best reserved for the operating room in severely affected children.
Radiographic evaluation provides useful information about the subglottis, trachea, and larger bronchi and therefore complements the flexible endoscopic examination. Lateral and anteroposterior plain films of the neck demonstrate the patency of the airway lumen and the presence of mass lesions. The anteroposterior high-kilovoltage technique is particularly useful for depicting the upper airway, as it enhances the tracheal air column and deemphasizes the bony cervical spine. Videofluoroscopy may be helpful for evaluating dynamic airway problems such as hypopharyngeal collapse and tracheomalacia. The barium swallow is useful to detect aspiration related to vocal cord paralysis, posterior laryngeal cleft, or H-type tracheoesophageal fistula and external compression from vascular lesions. CT and magnetic resonance imaging (MRI) are useful for obtaining specific information in selected cases (eg, vascular compression of tracheobronchial tree) but are not a substitute for endoscopic evaluation. A diagnosis is usually established by the above studies. Diagnostic rigid endoscopy is needed when (1) the diagnosis remains in question, (2) the previous evaluation suggests a subglottic lesion, and (3) a second significant distal lesion in the airway is suspected in addition to the diagnosis of a more obvious proximal lesion in the upper airway. Rigid airway endos-copy may also be necessary for therapy (eg, for removing laryngeal papillomas).
CONGENITAL MALFORMATIONS
The clinical manifestations associated with congenital anomalies of the larynx include respiratory obstruction, stridor in infants or hoarseness in older children, a weakened or abnormal cry, dyspnea, tachypnea, aspiration, and sudden death.
LARYNGOMALACIA
The pathogenesis of laryngomalacia, which is the most common cause of stridor in the newborn, is not completely understood. The cartilages of the infantile larynx are very flexible. As the infant inspires, the laryngeal skeleton is not stiff enough to keep the laryngeal lumen fully open. The infant epiglottis assumes a pronounced tubular or omega shape, and the aryepiglottic folds and false vocal cords are drawn into the laryngeal lumen, which results in a substantial narrowing of the lumen on inspiration.
The stridor of laryngomalacia may be present at birth but more often occurs about several weeks after birth and increases in severity. The child breathes more comfortably when relaxed and is usually more stridorous when agitated. The noise may be lessened when the child is on his or her side or when prone and worsens when supine.
Once other causes for stridor are ruled out, the treatment of this condition is usually close observation. As the child grows, the cartilages become more rigid and support the larynx, so the stridor resolves. Most children will outgrow the condition by 12 to 18 months. More severe laryngomalacia may cause failure to thrive secondary to airway obstruction and poor feeding or nighttime obstructive symptoms with significant oxygen desaturation. In these relatively rare cases, surgical trimming of the supraglottis (supraglottoplasty) is recommended. However, in most infants, positioning and using high-calorie formula will avoid the need for surgical intervention.
TRACHEOBRONCHOMALACIA
Tracheomalacia is an abnormal collapse of the trachea severe enough to produce symptoms of airway obstruction. Similarly, bronchomalacia is airway collapse in the bronchi and tracheobronchomalacia involves both. Mild tracheobronchomalacia is common and self-limited, whereas severe tracheobronchomalacia is life-threatening, and heroic measures may need to be considered, such as tracheostomy with positive-pressure ventilation. Tracheobronchomalacia may be primary or secondary to other pathology (eg, tracheoesophageal fistula, cardiac and vascular abnormalities, or cervical or mediastinal masses). Usually no treatment is required for primary tracheobronchomalacia, as the disease is self-limiting with resolution over a few years. Parents require substantial support and education, including teaching them cardio-pulmonary resuscitation, especially if the child has recurrent episodes of apnea and obstruction. In severe cases of tracheobronchomalacia, the potential risks and benefits of any therapies need to be carefully balanced.
SUBGLOTTIC STENOSIS
Congenital subglottic stenosis can cause significant stridor in the neonate or in the early months of life. Narrowing of the subglottic airway can occur for the following reasons: the first tracheal ring is trapped within the cricoid cartilage, there is a deformity of the cricoid cartilage, or there is excess soft tissue within the cricoid cartilage. The diagnosis is made by rigid endoscopy under general anesthesia.
Only stenosis sufficient to produce signs of respiratory distress requires treatment. In the past, treatment often meant a tracheostomy and waiting for the subglottic space to grow with the child. Currently, if the obstruction is sufficiently severe to require a tracheostomy, early surgical correction may avoid this procedure. In contrast, acquired subglottic stenosis from intubation injury often requires a tracheostomy with subsequent surgical correction to achieve decannulation. These children are often graduates of the neonatal nursery and have many other medical problems that need to be managed. Laryngeal-tracheal reconstruction for these complex airway abnormalities, provided today in most tertiary referral pediatric centers, has a high success rate of returning these children to a normal laryngeal and respiratory function.
WEBS, CYSTS, AND LARYNGOCELES
Partial or complete glottic webs can occur with aberrant development of structures in and around the laryngeal inlet in the embryo. Abnormal voice and, in more severe disease, stridor and respiratory distress can be the presenting signs. Tracheostomy can be lifesaving in the more complete glottic webs. Because there is an association between glottic web and velocardiofacial syndrome, children with glottic webs should have genetic consultation and genetic testing for 22q11 gene deletions.
Congenital cysts of the larynx arise from the mucus-secreting epithelium in the supraglottic region and occasionally in the subglottic space. Presenting symptoms include stridor and sometimes hoarseness. These must be distinguished from vallecular cysts that, if large, seriously interfere with swallowing and breathing. Subglottic cysts may be congenital, but they are usually secondary to prolonged or traumatic intubation. In either case, the endoscopic CO2 laser can be used to remove the cyst.
Laryngoceles are epithelium-lined diverticula that originate from the laryngeal ventricle. They can present internally in the larynx with airway obstruction or externally as a neck mass. Total excision of the cyst by external approach is the treatment of choice, but the endoscopic CO2 laser may be useful in selected cases. Thyroglossal duct cysts can present at birth as an obstructive lesion at the base of the tongue.
LARYNGOTRACHEOESOPHAGEAL DEFECTS
Incomplete formation of the tracheoesophageal septum can leave abnormal connections between the food and air passages. Clefts range from a slight deepening of the interarytenoid notch to a complete absence of the tracheoesophageal septum to the carina. The conventional classification system is shown in eFigure 371.1 . Symptoms may vary according to the length of the cleft. The child with a significant cleft will present with recurrent aspiration, failure to thrive, or life-threatening respiratory events. Small clefts are often difficult to demonstrate radiographically or endoscopically and require a high degree of suspicion to be diagnosed early. Surgical repair is indicated for all clefts with functional impairment. Extensive clefts are best repaired using extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass to permit unhindered surgical access to the entire length of the larynx, trachea, and esophagus.
VOCAL FOLD PARALYSIS
The possible causes of vocal fold paralysis in children are presented in Table 371-5. The symptoms of unilateral vocal fold paralysis are often so mild that the disorder often goes unnoticed. Unilateral recurrent laryngeal nerve paralysis results in the affected fold assuming a midline or slightly abducted position, and the cry is weak. The cry usually returns to near normal because the unaffected vocal fold compensates for the paralyzed one and because of synkinetic reinnervation of the affected vocal fold. Aspiration of liquids may occur if the normal vocal fold fails to compensate for the paralyzed one and there is incomplete laryngeal closure during deglutition. On inspiration, the normal vocal fold abducts completely to create an airway adequate for all except the most strenuous exercise. Superior laryngeal nerve injury results in paralysis of the cricothyroid muscle on the injured side. Decreased tension of the vocal fold accounts for the slight decrease in vocal range that is characteristic of superior laryngeal paralysis. Treatment may be required for unilateral vocal fold paralysis. Options include ansa-RLN reinnervation and laryngoplasty (surgical medialization of the paralyzed fold by injection or implant) to improve the voice or to decrease aspiration.
Table 371-5. Causes of Vocal Fold Paralysis
|
Congenital |
|
Central nervous system disease |
|
Birth trauma to head or neck |
|
Cysts (neck or chest) |
|
Neoplasm (Intracranial, Cervical, Thoracic) |
|
Benign |
|
Malignant |
|
Inflammatory |
|
Infection (viral) |
|
Degenerative disease (rheumatoid arthritis) |
|
Metabolic Disease |
|
Diabetes mellitus |
|
Heavy metal poisoning (As, Pb) |
|
Trauma (Includes Surgery) |
|
Blunt or penetrating (neck, head, chest) |
|
Intubation |
|
Surgical injury to vagus or recurrent laryngeal |
|
nerves in neck or chest |
|
Neurological |
|
Central nervous system disease |
|
Neuromuscular disease (eg, myasthenia gravis) |
|
Neurotoxic medication (eg, vincristine) |
|
Vascular |
|
Cardiovascular anomalies |
|
Cardiac failure (left heart enlargement) |
Bilateral recurrent laryngeal paralysis is usually characterized by marked airway obstruction and a good voice; both vocal folds are paralyzed in the midline or in a slightly abducted position. Management of symptomatic bilateral vocal fold paralysis requires prompt airway intervention, either intubation or tracheostomy, to relieve the airway obstruction. If the cause of the vocal fold paralysis is treatable (such as posterior craniotomy for Arnold-Chiari malformation) or if it resolves (such as with Guillain-Barré syndrome), the vocal folds may regain their mobility, permitting extubation or decannulation. If the paralysis is permanent, several procedures have been advocated to create an airway adequate to allow decannulation. Partial arytenoidectomy or unilateral vocal fold lateralization by either endoscopic or external methods allows one of the vocal folds to be permanently lateralized. There is a trade-off of airway for voice in this situation—the improvement in airway is often offset by reduced volume of the voice.
INFLAMMATORY AND INFECTIOUS DISORDERS OF THE LARYNX
VIRAL INFECTIONS
Viral laryngitis is often a component of upper respiratory infection (see also Chapter 241). Laryngeal manifestations usually include a hoarse, raspy voice, which is related to edema of the vocal folds, but airway obstruction is rare. Humidification, throat gargles, and voice rest are recommended for symptomatic relief. Laryngotracheobronchitis, or croup, is a common disorder of early childhood that is potentially life-threatening.
LARYNGOTRACHEOBRONCHITIS (CROUP)
Epidemiology
Viral laryngotracheobronchitis is most prevalent from age 3 months to 3 years and peaks during the second year of life, and it is more common in boys than girls. Most cases occur in the late fall and early winter, reflecting the epidemiological patterns of the various agents. Human parainfluenza virus types I and II account for most cases of croup in young children. Sporadic and sometimes severe cases of croup may be associated with other types of human parainfluenza virus, influenza virus types A and B, respiratory syncytial virus (RSV), measles, and a variety of other viruses. RSV is a major cause of lower respiratory tract infection in young children, and croup is its least common clinical manifestation. However, because a high percentage of young children admitted to the hospital with acute lower respiratory tract disease have high RSV isolates, this pathogen cannot be discounted as a cause of croup.
Pathophysiology
Viral upper respiratory tract infections usually affect the mucosa of the nose and nasopharynx first and then spread to involve the larynx and tracheobronchial tree. Under the mucosa of the subglottis of the young child is a generous subepithelial connective tissue space that permits submucosal edema formation with narrowing of the airway. The barking cough and stridor characteristic of croup generally result from edema of the subglottic airway. The cricoid cartilage is a complete ring, so the airway is narrowest here, and swelling cannot occur outward. Therefore, even minimal edema can cause airway obstruction, with symptoms being more likely in young children, because their small airway diameter increases resistance to airflow.
In croup, stridor is most common on inspiration because the negative inspiratory pressure tends to collapse the already partially narrowed extrathoracic structures. Biphasic stridor occurs if the subglottis is extremely narrow. Copious secretions produced secondary to inflammation will also clog the airway, producing secondary obstruction in an already narrow region.
Diagnosis and Treatment
The differential diagnosis of viral laryngotracheitis includes spasmodic croup, bacterial croup and tracheitis, retropharyngeal abscess, angioneurotic edema, and foreign bodies of the aerodigestive tract. The most important element in evaluating children with croup is distinguishing those with croup from those with epiglottitis, although this is far less a concern in regions where Haemophilus influenzae vaccination has almost eliminated epiglottitis (see below). Managing croup consists of supportive treatment with cool mist. At home, this can be achieved by a cool mist vaporizer or placing the child in a bathroom filled with steam from the shower or by taking the child outdoors in the cool night air. In the hospital, initial management consists of hydration, cool mist with or without supplemental oxygen, and steroid medication. Racemic epinephrine is reserved for severe cases.
Prospective, randomized studies have demonstrated that steroid therapy decreases the length and severity of the respiratory symptoms associated with viral croup. Dexamethasone is the preparation most frequently used, in doses between 0.6 and 1.0 mg/kg. Many investigators use a croup score, both for the initial triage of the child and to evaluate response to medical therapy but the value of these scoring systems in routine clinical pratice remains to be proven. Whatever method is used, sound medical judgment is needed to predict the onset of respiratory failure, hypoxia, and hyper-carbia. Most infants improve over 48 to 72 hours without further treatment, but some require intervention for impending respiratory failure. Limited data suggests that helium/oxygen mixtures (HELIOX) may have some benefit in infants without high oxygen content requirements but with impending respiratory failure. Intubation is rarely necessary, and if it is required, the presence of an underlying congenital lesion such as subglottic stenosis or a vascular ring should be considered. Recurrent episodes of croup may occur in otherwise normal children, but a suspicion of another possible airway lesion should be maintained, especially in younger children.
BACTERIAL INFECTIONS
Acute epiglottitis is an infection of the larynx with rapid swelling of the epiglottis and increasing inspiratory difficulty. Since the introduction of the Haemophilus B vaccine, this disorder is an increasingly uncommon infection of the supraglottic larynx. The management of epiglottitis is discussed in Chapter 263. H influenzae still remains the most common bacterial infection of the larynx, especially in regions where vaccination is unavailable. Bacterial infections by Streptococcus, Staphylococcus, and others have also been reported as causes of supraglottic infection.
Diphtheria is an example of a bacterial infection that can involve the larynx and other areas of the upper aerodigestive tract (see Chapter 261). Tuberculosis of the larynx can occur and is usually associated with a generalized pulmonary infection.
SPASMODIC CROUP
In spasmodic croup, an otherwise healthy child wakes up in the middle of the night with a barky cough and mild to severe inspiratory stridor. The condition variously responds to humidification or exposure to cold air. The next day, the child appears healthy, but the cyclic episode repeats itself on two or three successive nights. The repetitive nature of this problem and its variable response to therapy are quite characteristic. The etiology is not understood. Absence of any signs of upper respiratory tract infection separates this entity from acute infectious croup and suggests an allergic origin. Gastroesophageal reflux may be a factor in some children by causing a baseline airway inflammation that, when challenged with a viral upper respiratory infection, creates additional edema that causes significant airway obstruction. Failure of typical therapies, especially in conjunction with obstructive symptoms during allergic episodes, may be cause to suspect a subglottic stenosis. Such a reduction of the already restricted subglottic space may make an otherwise normal child unable to tolerate even mild inflammation associated with allergic sensitivities.
ALLERGY
The larynx is susceptible to the same allergens that affect other parts of the upper aerodigestive tract. When the mucosa of the larynx is involved, edema of the vocal cords results in a hoarse voice and a dry, scratchy feeling in the throat. The larynx may also be irritated by an allergic postnasal drip. Treatment of allergic manifestations in the larynx includes avoiding the offending allergen, systemic antihista-mines, humidification, systemic or aerosol corticosteroids, and desensitization.
ANGIONEUROTIC EDEMA
Angioedema consists of localized edema of rapid onset in response to a variety of triggers, including infection, drugs (especially angiotensin-converting enzyme inhibitors and aspirin), exercise, allergens, insect bites, serum sickness, collagen vascular diseases, and malignancy. It commonly affects the upper airway and can cause life-threatening obstruction. Subcutaneous epinephrine (0.01 mL/kg of 1:1000 concentration) provides rapid relief. A variety of antihistamines, such as diphenhydramine, provide longer-term control. Occasionally, systemic steroids are required to control the problem. Hereditary angioneurotic edema is a rare disorder and is discussed in Chapter 189.
GASTROESOPHAGEAL REFLUX
Gastroesophageal reflux with passage of gastric contents into the pharynx is normal in infants and young children. When the larynx’s anatomy and physiology are normal, the refluxed gastric material never enters the airway. When laryngeal anatomy is abnormal, as with a laryngeal cleft, or if the normal protective reflexes are absent because of neuromuscular disease, the gastric material can impinge on laryngeal structures and may enter the airway. Even infrequent (such as once every several days) exposure can cause laryngeal inflammation and may aggravate many laryngeal and upper airway conditions in infants and children. In children with chronic cough, oropharyngeal dysphagia, vocal fold granuloma, airway obstruction, apnea, asthma, recurrent croup, laryngomalacia, chronic laryngitis, and subglottic stenosis, gastroesophageal reflux should be considered as an underlying etiologic factor (see Chapter 394).
MASSES AND TUMORS OF THE LARYNX
VOCAL FOLD NODULES
Hoarseness can result from the formation of vocal fold nodules as a result of persistent vocal misuse or abuse such as by shouting, screaming, or singing. These masses occur at the junction of the anterior and middle one third of the vocal cords, which is the point of maximal vocal fold vibration. The size of the nodules and the resultant hoarseness usually fluctuate, depending on the child’s vocal use or abuse. It is important to diagnose the cause of hoarseness in young children by performing a flexible laryngoscopy, especially to rule out other causes, such as papilloma. Once the diagnosis of benign vocal lesions is made, a period of observation is appropriate in young children. In older children, if the problem persists, nodules are best managed by voice and speech therapy. Occasionally, nodules that have fibrosed from long-standing vocal abuse may not respond to conservative management and will require microlaryngoscopic removal. If the child continues with poor vocal habits, the nodules will likely recur; therefore, speech therapy is an important adjunctive therapy.
PAPILLOMATOSIS
Although they are not considered true neoplasms, the wartlike lesions from recurrent respiratory papillomatosis are often referred to as the most common tumor of the larynx in children. The papilloma virus, especially types 6 and 11, is the cause of the lesions, with a particular predilection for the upper aerodigestive tract, especially the larynx. The “juvenile” type of this disease usually makes its presentation at 2 to 5 years of age, causing hoarseness and marked airway obstruction in severe cases. The course of the disease is characterized by multiple cycles of growth and regression. In many cases, a spontaneous remission occurs, usually around puberty. None of the recommended treatments—surgical excision, laser excision, cryotherapy, ultrasound, interferon, or topical agents—has been consistently shown to cure the disease. The goal in treating these patients is to maintain a good voice and an unobstructed airway by repeated functional excision of the papillomas. There is an incidence of malignant transformation, making this a serious disease. The effect of the human papillomavirus vaccine on this disease is unknown but may reduce the occurrence of this difficult problem in the future.
HEMANGIOMAS
These lesions may occur in the larynx, primarily in the subglottic area. They are often associated with other cutaneous hemangiomas but also occur as isolated lesions. With crying or straining, these lesions increase in size and cause significant airway obstruction. They appear as asymmetric masses on anteroposterior neck radiography, but the diagnosis must usually be confirmed by microlaryngoscopy. Because many hemangiomas of infancy tend to involute after a period of growth during the first year, close observation is the initial treatment of choice. If obstructive symptoms require more aggressive treatment, high-dose steroid therapy can be instituted to limit the hemangioma’s growth. If the lesion fails to decrease in size, options include endoscopic or open surgical excision or tracheostomy. Recent experience suggests that the CO2 laser or photoangiolytic laser such as KTP (potassium-titanyl-phosphate) laser can partially remove hemangiomas without airway obstruction or hemorrhage. Increasingly, removing the hemangiomas by external surgery followed by brief intubation is the most effective and permanent solution to the problem without impacting the voice.
APPROACH TO THE CHILD WITH DYSPHONIA
The approach to the child with dysphonia depends on the child’s age and whether there is accompanying airway compromise. In very young children—especially those who have had surgical procedures such as a patent ductus arteriosus (PDA) ligation, other cardiac surgery, neurological compromise, or prolonged intubation—a paralyzed true vocal fold should be suspected. Dysphonia may also be the first presenting symptom in a child with respiratory papillomatosis. Young children with dysphonia that persists more than a short time warrant consultation for evaluation and flexible laryngoscopy. In older children, the overwhelming majority will have benign vocal fold nodules. However, other pathology that requires more urgent intervention is possible. Consultation by an otolaryngologist should be considered for children who have consistent, rather than intermittent dysphonia, when the severity of dysphonia is progressively worsening, or in children with complete aphonia. Other concerning associated symptoms include swallowing difficulties, pain, respiratory difficulties, a history of trauma, or other systemic conditions such as rheumatoid arthritis. If there is a history of recent intubation or if the dysphonia persists for greater than several months, consultation should also be considered. A growing number of tertiary pediatric centers provide expertise in voice centers or clinics with sophisticated diagnostic tools geared toward children. In addition, these centers generally provide an interdisciplinary team that includes a speech therapist and specialized nursing care to allow for improved therapeutic interventions for children who have laryngeal pathology.
LARYNGOTRACHEAL TRAUMA
Blunt or penetrating injuries may occur with sports or motor vehicle accidents. These injuries may result in mucosal laceration, laryngeal hematomas, vocal fold paralysis, or fractures of the larynx. Patients present with various degrees of neck pain, hoarseness, hemoptysis, and airway obstruction. Physical examination may reveal anterior neck tenderness, crepitance, and absence of the normal prominence of the thyroid cartilage. Proper treatment requires recognizing the nature of the injury and protecting the airway.
Endotracheal intubation can cause mucosal lacerations, granulomas of the vocal folds, dislocation of the arytenoid cartilage, and subglottic stenosis. Mucosal ulcerations and pressure necrosis can occur as the mucosa is compressed by the pressure of a tight-fitting endotracheal tube against the unyielding cricoid cartilage surrounding the subglottic space; resultant chondritis or mucosal fibrosis can produce mature scar tissue that significantly narrows the subglottic lumen. A congenital smaller-than-normal airway, a large endotracheal tube, inadequate fixation of the tube, prolonged intubation, mechanical ventilation, multiple intubations, infection, and cuffed endotracheal tubes all increase the individual’s risk of developing subglottic stenosis. Treatment is the same as that described for subglottic stenosis of congenital origin, relying mainly on open laryngotracheal reconstruction techniques. For mild to moderate degrees of stenosis, endoscopic dilation and topical mitomycin application is also an appropriate option.
FOREIGN-BODY ASPIRATION
Foreign body aspiration is discussed in detail in Chapter 118.
TRACHEOSTOMY
There are four major indications for long-term tracheotomy in children: airway obstruction, ventilatory support, severe obstructive sleep apnea, and pulmonary toilet. A detailed discussion of tracheostomy management is provided in Chapter 124.