J. Paul Willging
Disorders of feeding and swallowing are being recognized more frequently both in healthy infants and young children as well as in children with concomitant airway disease. This chapter describes esophageal anatomy and the physiology of swallowing, as well as the diseases and anatomic lesions that can cause swallowing dysfunction. Common disorders, such as gastroesophageal reflux, and less common disease, such as eosinophilic esophagitis, are outlined. The role of the otolaryngologist in diagnosis and treatment of dysphagia and esophageal disease is emphasized, particularly with the use of endoscopic evaluation of swallowing. Readers should note the common association of airway disease with disorders of swallowing.
The esophagus is a conduit connecting the hypopharynx and the stomach. It is predominantly a left-sided structure. It has circular muscle fibers surrounding the lumen, with an outer layer of longitudinally oriented muscle fibers. It has no serosal layer. A combination of voluntary and involuntary muscle tissue is present in the esophagus. The striated muscle is located superiorly, with smooth muscle located in the distal half.
The upper esophageal sphincter (UES) is composed of striated muscle from both the cricopharyngeus and the inferior pharyngeal constrictor muscles. Tonic contraction prevents material in the esophagus from refluxing into the hypopharynx, thus reducing aspiration risk. The UES also prevents the unintentional passage of air from the pharynx into the stomach during respiration.
The UES relaxes in coordination with bolus transfer into the pharynx for swallowing. The tonic contraction within the UES is inhibited during the act of swallowing, and due to the attachment of the cricopharyngeus muscle to the cricoid plate, the UES is actively opened when the larynx elevates with swallowing. The neural control of the events associated with swallowing occurs in the brainstem.
The lower esophageal sphincter (LES) is also under tonic control, and prevents the reflux of gastric contents into the esophagus. The LES relaxes in response to neural inhibition of the muscle, triggered by transit of food material with distension of the lower esophagus.
Tracheoesophageal Fistula with Esophageal Atresia
This congenital anomaly is seen in 1 in 3000 live births.1 The most common variant of this anomaly, accounting for 85% of cases, involves an atretic upper pouch of the esophagus with the distal stump of the esophagus connecting to the posterior tracheal wall. Classic theory suggests they develop as a result of incomplete separation of the respiratory and digestive division of the foregut anlage. The primitive foregut is divided into an anterior airway and posterior esophagus by the medial advancement of the lateral foregut grooves. Failure of the two grooves to fuse in the midline leads to the development of a tracheoesophageal fistula (TEF). Abnormal directional growth of these grooves leads to esophageal atresia (EA).2 An alternate explanation for the development of these disorders suggests that insufficient blood supply to the developing esophagus may lead to areas of necrosis and development of an atretic segment. A TEF would develop from abnormal fusion of the developing trachea and esophagus due to abnormally directed growth vectors.3
Infants with EA are identified early in life secondary to the feeding and respiratory difficulties that develop. Coughing, choking, and pneumonia are often seen in patients with EA, as the overflow of contents from the nonpatent upper esophageal segment can be aspirated. Gastric distension with positive pressure ventilation with a mask or endotracheal tube is seen with a TEF. The presence of EA or a TEF should prompt investigation for other associated anomalies as 50% of patients will have other abnormalities such as congenital heart disease (20%); gastrointestinal (13%); genitourinary (10%); musculoskeletal (9%); or facial anomalies (5%).4
Esophageal Motility Disorders
Cricopharyngeal achalasia (CPA) is characterized by failure of the UES to relax in response to propulsion of a bolus through the pharynx. The cricopharyngeus muscle may be hypertrophic or may demonstrate fibrosis. The lack of relaxation can be demonstrated on contrast radiographic studies of the esophagus as a cricopharyngeal bar protruding into the lumen of the UES segment of the esophagus during swallowing. CPA causes pharyngeal dysphagia. Treatment may include dilation treatments. Botulinum toxin injections may also provide temporary resolution of symptoms. Cricopharyngeal myotomy is a definitive treatment. In all children with CPA, an evaluation for an Arnold-Chiari malformation must be obtained due to their common association.5 A common presenting symptom of patients with CPA is choking associated with feeding. The child will often shift their diet preferences away from foods of increased texture toward liquids and pureed materials.
Achalasia of the LES presents as a slowly progressive dysphagia for solids and liquids. This is an uncommon cause of dysphagia in children, most commonly affecting middle-aged adults. The proximal esophagus dilates, and a progressive narrowing of the lower esophagus creates the classic “bird-beak” deformity seen on radiographic studies. Similar to CPA, serial dilation procedures and botulinum toxin injections are effective treatments to temporize the condition. Longitudinal myotomy of the distal 2 cm of the esophagus and 2 cm of the anterior gastric wall down to the submucosa (modified Heller procedure) is generally definitive treatment for the condition.6
Gastroesophageal reflux disease (GERD) is the most common esophageal disorder in children. Gastroesophageal reflux occurs when gastric contents pass retrograde from the stomach into the esophagus. Physiologic reflux occurs in normal individuals with episodes occurring infrequently and associated with rapid clearance of the refluxate from the esophagus. Physiologic reflux causes no irritation to the esophageal mucosa. When the esophageal mucosa is exposed to an increasing frequency of reflux events, or the duration of acid exposure within the esophagus increases with each reflux event, the mucosa becomes inflamed. Chronic inflammation of the esophageal mucosa by reflux is a hallmark of GERD. In children, GERD may have a host of manifestations, including irritability, failure to thrive, food refusal, cough, dysphagia, stridor, hoarseness, bronchospasm, recurrent pneumonia, and apnea. Clinically apparent regurgitate episodes need not be present with GERD.
Reflux events are normally cleared from the esophagus. Saliva and secretions produced by mucus glands within the esophagus neutralize gastric acid. The peristaltic action within the esophagus clears gastric secretions from the esophagus protecting the lining of the esophagus from the inflammatory actions of the reflux material. No single symptom or symptom complex is diagnostic of GERD. Clinical suspicion may lead to specific testing to determine the presence/severity of gastroesophageal reflux.
Tests for GERD
Esophageal pH Monitoring
Intraluminal pH is monitored and recorded continuously for 24 hours.7 The length of time the esophagus is exposed to a pH less than 4 is determined. The number of episodes of acidic reflux is determined, and the number of reflux episodes lasting more than 5 minutes is determined. The probe is positioned within 3 cm of the LES for accurate recordings. To increase the sensitivity of the study, a second sensor can be positioned at the UES to assess the number of reflux events ascending to the level of the pharynx. Such pH monitoring can detect only acidic events reaching the level of the sensor. The volume of the reflux event cannot be determined. Gastric contents that have been buffered to a neutral pH by foods, bile, or medications do not trigger the sensor as an event. Esophageal pH monitoring is useful for evaluating the effectiveness of anti-acid and antisecretory therapies for gastroesophageal reflux.
Combined Multiple and Intraluminal Impedance with pH Monitoring
A probe that measures a change in the impedance between pairs of electrodes allows a determination of the presence of liquid, air, or solids in the esophagus passing the probe.8 Multiple pairs of electrodes allow a reflux event to be followed as it ascends the esophagus and again as it is cleared from the esophagus. A pH sensor is incorporated into the sleeve of the sensor to allow a determination of the acidic or neutral nature of the reflux event.
Impedance monitoring provides significantly more information regarding reflux events than does a pH probe study. Antegrade and retrograde flow through the esophagus can be measured. Acidic and pH neutral reflux events can be identified. The height of a single event can be followed and the rate of clearance from the esophagus defined.
Contrast Radiographic Studies
The upper gastrointestinal radiographic study is useful in determining anatomic abnormalities of the upper gastrointestinal tract, but it is a limited study for the diagnosis of GERD. Reflux may be seen during the study, but the absence of identified reflux events does not rule out the diagnosis of GERD. Conversely, some reflux events may be seen in normal individuals without disease.
Radiolabeled food materials are ingested and prolonged imaging is obtained to provide a means of determining the rate of gastric emptying and identifying reflux events. Pulmonary aspiration of a reflux event may be recorded by the presence of label within the lung fields. A negative test does not rule out the possibility of pulmonary aspiration of refluxed materials due to the episodic nature of the events. These nuclear medicine scans are not recommended for the routine evaluation of children suspected of having GERD.
Endoscopy with Biopsy
Esophagogastroduodenoscopy allows visualization of the esophageal mucosa, and permits biopsy specimens to be obtained from the proximal and distal esophagus. The stomach and duodenum are also examined. Breaks in the distal esophageal mucosa are the most reliable sign of reflux esophagitis. Mucosal erythema, pallor, and altered vascular patterns are suggestive but not specific findings of reflux. Histologic findings suggestive of gastroesophageal reflux are eosinophilia, elongation of the rete pegs, vascular hyperplasia, and dilation of intercellular spaces.
Extraesophageal reflux (reflux reaching the hypopharynx causing laryngeal irritation) is difficult to definitively diagnose. There is a poor correlation between the visual appearance of the larynx on fiberoptic examination and the results of pH probes and esophageal biopsies.9 A reflux event that spills into the endolarynx will not be readily cleared, causing prolonged caustic irritation to the laryngeal structures. The number of extraesophageal reflux events required to cause pathologic changes within the larynx therefore will be much less than the number of events required to produce esophageal pathology.
Treatment of GERD
Medical treatment of GERD is reserved for children with excessive emesis episodes, irritability related to gastroesophageal reflux, failure to thrive, or recurrent respiratory symptoms. Antacids neutralize gastric acid. High doses of aluminum medications may reach toxic levels in children, causing neutropenia, anemia and neurotoxicity.10 Only sporadic use of aluminum-containing antacids is recommended in children.
Prokinetic agents increase the resting tone of the LES, increasing esophageal peristalsis and accelerating gastric emptying. All these mechanisms reduce gastroesophageal reflux events. Cisapride provides the greatest prokinetic effect and is least likely to induce bronchospasm. Cases of prolonged Q-T interval and fatal arrhythmias have been associated with cisapride when used concurrently with macrolide antibiotics and antifungal medications.11 The use of cisapride should be limited to select infants failing dietary changes and antisecretory medical therapy. Careful monitoring is required for the duration of its use, limiting the utility of this medication.
Metoclopramide facilitates gastric emptying; it is associated with lethargy, irritability, and may in rare cases cause irreversible tardive dyskinesia. Sucralfate adheres to the surface of the gastric ulcers and protects the esophageal mucosa from the corrosive effects of gastric acid. As it contains aluminum, care must be taken in children.
Histamine receptor antagonist (H2 blockers), ranitidine and cimetidine, suppress gastric acid production. They reduce the symptoms of GERD and promote healing of the histologic changes associated with esophagitis.
While H2 blockers are often the starting point of medical treatment for gastroesophageal reflux, proton pump inhibitors (PPIs) are the most effective acid suppressants. Lansoprazole (Prevacid) and omeprazole (Prilosec) come in formulations that are easily administered and well tolerated in children. While once daily treatment is the norm, impedance probe verified breakthrough of acid production warrants twice daily treatment. There is concern regarding the safety of prolonged PPI use. An increased risk of osteoporosis and associated bone fractures has been described with treatment durations longer than one year. Increased rates of community-acquired pneumonia, gastroenteritis, and Candida infections have also been associated with prolonged use of PPIs.12
Surgical treatment of GERD is reserved for patients with severe, medically refractory gastroesophageal reflux symptoms. Fundoplication procedures, of which the Nissen procedure is the most common, attempt to recreate a functional LES by wrapping a portion of the greater curvature of the stomach around the esophagus. The primary complication associated with this procedure is gas-bloat syndrome, retching, gagging, dumping syndrome, and recurrent reflux symptoms.
Dysphagia in Children
Swallowing is an intricate process that requires multiple cranial and cervical nerves and the precise coordination of numerous muscles of the lips, tongue, palate, pharynx, larynx, esophagus, and chest. Any condition that upsets the delicate interplay between components of the swallowing mechanism may result in dysphagia.
Changes associated with the growth and maturational development of the upper aerodigestive tract in children may create pathophysiology that differs substantially from that seen in adults with feeding and swallowing disorders. Specifically, the anatomy of the oral cavity and the anatomic relationships of the mouth, pharynx, and larynx undergo continual change over the first several years of life. Similarly, the process of food ingestion evolves from reflexive sucking to mastication and the neurologic control mechanisms that coordinate swallowing with respiratory activity undergo continual development. If the child is unable to adapt to changes in structure or if neurologic function is impaired, swallowing will be compromised, and problems may arise that could lead to chronic pulmonary disease or malnutrition.
The improved survival rates of children with a history of prematurity, low birth weight, and complex medical conditions that affect the structure and function of various components of the swallowing mechanism has resulted in an increased incidence of pediatric dysphagia.13–16 In view of this increase, there is a high likelihood of encountering these patients in clinical practice.
Normal Swallowing Physiology
The neural control of swallowing is complex. Afferent sensory inputs are integrated in the brainstem, and efferent pattern generators direct the motor responses to produce an efficient and safe swallow. A sequential discharge of neurons is provided to the muscles in the pharynx, larynx, and esophagus. Four neural components have been well described: (1) afferent sensory fibers contained in the cranial nerves; (2) efferent motor fibers contained in the cranial nerves and the ansa cervicalis; (3) cerebral, midbrain, and cerebellar fibers that synapse in the midbrain; and (4) the paired swallowing centers located in the brainstem.17,18
Three Phases of Swallowing
The act of swallowing (deglutition) allows food or liquid bolus to be transported from the mouth to the pharynx and esophagus, through which it enters the stomach. Normal deglutition is a synchronized process that involves an intricate series of voluntary and involuntary neuromuscular contractions. This process is typically divided into three distinct phases: oral, pharyngeal, and esophageal. Each of these phases facilitates a specific function. Problems in one or more phases of swallowing constitute dysphagia.
The oral phase is under voluntary neural control and begins with the introduction of food material into the mouth. Coordinated contractions of the tongue and muscles of mastication modulated by mechanoreceptors organize this material into a bolus. The tongue elevates as the bolus is held in the central groove of the tongue, and moves in a peristaltic fashion against the palate. The posterior propulsion of the bolus by the tongue into the pharynx triggers the onset of the involuntary swallow reflex.
This phase requires complex sensory and motor integration. The facial nerve innervates muscles of the face, and branches of the mandibular division of the trigeminal nerve innervate muscles associated with mandibular movement. The tongue requires coordinated movement of four intrinsic muscles innervated by the hypoglossal nerve, and four extrinsic muscles innervated by branches from the ansa cervicalis.17The vagus and glossopharyngeal nerves innervate the muscles of the palate, pharynx, and larynx. Branches from the maxillary division of the trigeminal, facial, glossopharyngeal, and vagus nerves provide sensory innervation. Neural control of the swallowing process is at the level of the brainstem in infancy—it is predominantly a reflexive act. As cortical maturation occurs and experience with food materials accumulates, increasing volitional control is acquired.
The pharyngeal phase of swallowing is largely involuntary. Pharyngeal swallows are initiated in an ordered sequential pattern in response to stimulation by food or secretions in the pharynx. Tactile receptors in the pharynx provide sensory stimulation to the medullary swallowing center via the trigeminal, glossopharyngeal, and vagus nerves.19 The medullary swallowing center initiates a swallow by stimulating the nucleus ambiguus and the dorsomedial vagal nucleus. The soft palate closes against the posterior pharyngeal wall to isolate the nasopharynx from the oropharynx as food is propelled posteriorly. The bolus is propelled through the oropharynx by the contraction of the pharyngeal muscles against the base of the tongue. Proprioceptive feedback adjusts the peristaltic activity for different food bolus sizes and consistencies.20
The pharynx serves as a conduit for food as well as air exchange. Precise coordination of breathing and swallowing is thus necessary during feeding. With the initiation of the swallow, respiration is concurrently inhibited and the larynx is pulled superiorly and anteriorly; this effectively moves the laryngeal inlet out of the direct path of the bolus. The true and false vocal folds close, and the epiglottis retroflexes over the laryngeal inlet with laryngeal elevation to further protect the distal airway. The upper esophageal inlet is pulled open with laryngeal elevation, and the peristaltic contractions of the pharyngeal constrictor muscles propel the bolus into the esophagus.
Food material falling into the laryngeal inlet stimulates mechanoreceptors and chemoreceptors, resulting in vocal cord closure and apnea. Apnea will be sustained until the noxious stimulus is cleared from the larynx. Hypoxia may result in the neonate due to the lack of respiratory reserve. An additional response to stimulation is the cough reflex; this may be triggered by direct laryngeal stimulation or stimulation of receptors within the trachea. It is important to note, however, that this reflex is absent in 75% of premature infants and 50% of newborns.21 Additionally, it may be compromised in infants who are neurologically impaired.
The esophagus is a conduit between the pharynx and the stomach, with muscular sphincters at either end in tonic contraction to keep the esophagus closed between swallows. The UES relaxes during swallowing, and is actively opened by laryngeal elevation to allow the food bolus to enter the esophagus. Peristaltic contractions propel the bolus down into the stomach. The LES relaxes to allow passage of the bolus. Tonic contraction of the LES prevents the reflux of gastric contents into the lower esophagus. Propagation of the peristaltic wave is dependent on the intrinsic myenteric plexus and vagal efferents.
Aspiration is the passage of solid or liquid material below the level of the vocal folds; the potential for this to occur is greatest during the pharyngeal phase of swallowing. Aspiration of small volumes of material may be cleared from the airway by normal mucociliary clearance or a cough. Large volumes of aspirated material may, however, reach the distal airway, leading to the possibility of aspiration pneumonia. Because oral secretions are laden with high concentrations of bacteria from the oral cavity, aspiration of these secretions may lead to chronic lung damage over time.22 For children whose strength and endurance is compromised due to developmental, neurologic, or other medical conditions, fatigue during feeding can increase the risk of aspiration.23
Signs and Symptoms of Swallowing Disorders
The presentations of feeding and swallowing disorders are diverse, with signs and symptoms that may range from obvious problems such as projectile vomiting, coughing, or choking to more subtle silent aspiration. Affected neonates may exhibit sucking difficulty, slow sucking, or sucking that is unaccompanied by effective swallow. If left untreated, these symptoms may result in failure to thrive. Parents or clinicians may see delayed or restricted oral motor skills for intake of food or liquid, retention of food in the mouth, coughing and gagging when feeding, nasal reflux of food or liquid, failure to gain weight, or respiratory symptoms (apnea, cyanosis, retractions, tachypnea, stridor) during or shortly after feeding.
Dysphagia should be suspected in children who have repeated episodes of respiratory infections and suffer chronic bronchial congestion. Children with metabolic disease, neuromotor impairment, or craniofacial anomalies are often affected with disorders of feeding and swallowing. Dysmorphic features often indicate the presence of syndromes commonly associated with dysphagia (e.g., Cornelia de Lange syndrome, Pierre Robin syndrome, velocardiofacial syndrome, VACTERL association—vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb abnormalities).24
Classification of Etiologies of Dysphagia in Children
The causes of pediatric dysphagia fall within five broad categories: structural abnormalities, neurologic conditions, cardiorespiratory problems, behavioral issues, and inflammatory or metabolic disorders.25Young children can have difficulties in swallowing that involve one or several of these issues.
Any anatomic abnormality from the nasal cavity to the gastrointestinal tract can potentially disrupt any phase of swallowing. Children with defects in the oral cavity or oropharynx, such as congenital craniofacial syndromes, cleft lip or palate, or macroglossia, may experience difficulty in the oral phase. Children with congenital defects of the larynx or trachea may develop feeding difficulties secondary to airway compromise during swallowing. Esophageal abnormalities may interfere with the transport of food material into the distal digestive tract. All these problems may create discomfort during feeding and may lead to feeding refusal and the development of behavioral feeding problems. In children who have undergone reconstructive procedures to correct anatomic anomalies, the behavioral issues may continue to predominate, thus perpetuating feeding problems.
Neurologic disorders comprise the most common etiology of pediatric feeding and swallowing disorders. Neuromotor impairment as a result of cortical dysfunction, abnormalities in the brainstem, or cervical cord injuries impacts the strength and efficiency of the oral and pharyngeal phases of swallowing, the adequacy of coordination of airway protection and swallowing, as well as overall alertness and the postural control necessary for safe and efficient feeding. In addition, these patients frequently present with esophageal issues such as impaired motility or GERD, further complicating their management.
Cardiorespiratory compromise often affects an infant's ability to initiate or sustain a coordinated suck–swallow–breathe sequence. Feeding often results in accompanying apnea or episodes of bradycardia, thereby affecting feeding endurance and often preventing adequate food intake. Problems with respiratory compromise may result in poor coordination or inappropriate timing of airway protection during swallowing, resulting in coughing, choking, or episodes of apnea, bradycardia, chronic noisy breathing, or wheezing, as well as chronic or recurrent pneumonia, bronchitis, or atelectasis.
Behavior-based feeding problems may stem from psychosocial factors, such as dysfunctional feeder–child interaction, poor environmental stimulation, conditioned dysphagia (a phobic response resulting from an aversive oral or pharyngeal experience or a painful feeding experience such as choking), or negative feeding behaviors. Behavioral responses exhibited by the child may include refusal to eat, rejection of certain foods or textures, and gagging or vomiting. Careful evaluation to eliminate the possibility of underlying physiologic factors before focused behavioral treatment of maladaptive feeding behaviors is essential.
Metabolic and Inflammatory Disorders
Metabolic abnormalities such as hereditary fructose intolerance or endocrine problems can interfere with swallowing. More commonly, inflammatory conditions such as GERD or eosinophilic esophagitis (EE) or food allergies can interfere with the development or maintenance of normal oral motor and feeding patterns. In young children, elimination of foods previously taken well is a hallmark of esophageal inflammation. EE is characterized by marked infiltration of the submucosa with eosinophils seen in esophageal biopsies. Gross disruption of esophageal architecture on esophagoscopy, with narrowings, furrows, or series of ring-like structures, have been described in children with EE. Treatment of EE includes the administration of swallowed aerosolized fluticasone as well as elimination of suspect foods that may be causing allergy. Allergy testing is important to identify foods that could be eliminated from the diet to reduce esophageal irritation.26
Diagnostic Evaluation of Dysphagia in Children
Videofluoroscopic Swallow Study
The videofluoroscopic swallow study (VFSS) is often considered the gold standard for evaluating infants and children with swallowing disorders.27 The VFSS allows for noninvasive assessment of the oral, pharyngeal, and esophageal phases of swallowing and the interrelationship of these phases. Additionally, VFSS enables the determination of consistencies and conditions for safe swallowing and allows a trial of compensatory and therapeutic techniques to improve the safety and efficiency of swallowing. These interventions include examining the patient's response to other textures, alternating presentations of liquid and solids, and exploring the therapeutic efficacy of modifications in bolus volume, nipple, or utensil types; pace of presentation; and body posture.
The disadvantages of VFSS include use of ionizing radiation with exposure to both the child and the feeder. Assessment of compensatory strategies such as positioning alterations, oral motor strategies, or alternation of food and liquid consistencies adds to the overall exposure time. Additionally, adding barium to liquid and food sometimes decreases a child's willingness to drink or eat during the study. Moreover, because adding barium significantly increases viscosity, preparing a true thin liquid is not possible. Last, the VFSS is not feasible for patients who take extremely limited amounts of liquid or food orally, as the child needs to ingest a sufficient amount of contrast for adequate imaging.
Esophagram and Upper Gastrointestinal Radiographic Studies
The esophagram and upper gastrointestinal radiographic studies examine the anatomy and function of the esophagus, stomach, and duodenum. Dynamic images are obtained as the bolus passes through the oropharynx, into the esophagus, and into the stomach. Careful assessment for a possible tracheoesophageal fistula requires an adequate volume of contrast to distend the esophagus. In patients who cannot swallow an adequate volume of contrast, a tube is passed into the esophagus, providing a means of demonstrating the fistulous tract. Abnormalities such as esophageal strictures, webs, vascular rings, foreign bodies, or achalasia may be identified (Figs. 12.1 and 12.2).
Fiberoptic Endoscopic Evaluation of Swallowing
First described by Langmore et al in 1988,28 fiberoptic endoscopic evaluation of swallowing (FEES) was initially used in the assessment of adults with feeding disorders. FEES has been used to evaluate children since the early 1990s.29
Figure 12.1 Esophagram of a 2-year-old infant with acute dysphagia to solids and mild stridor. Filling defect in mid-esophagus suggests foreign bodies.
Image courtesy: David E. Tunkel, M.D.
Figure 12.2 Pieces of crab shells removed at rigid esophagoscopy. Image courtesy: David E. Tunkel, M.D.
Indications for Pediatric FEES
The decision to use FESS for a child with feeding and/or respiratory symptoms depends on several clinical factors.30 Children who have never been fed orally or who accept only limited oral intake are poor candidates for VFSS. Such children can have FEES to assess laryngopharyngeal structure and function as well as management of secretions, sensory awareness, and spontaneous swallowing sequences.
The FEES examination is performed with the child resting in a sitting position in the lap of a caregiver. No sedation is required for the examination. An anatomic assessment of the larynx, vocal fold mobility, and hypopharynx is performed (Fig. 12.3). Food materials are offered that are developmentally appropriate, often using dyed liquids as well as easy-to-visualize solids and semi-solids. The efficiency the swallow is assessed, and the ability to protect the airway from various textures and presentation styles determined.
Fiberoptic Endoscopic Evaluation of Swallowing with Sensory Testing
Performed as an adjunct to FEES, fiberoptic endoscopic evaluation of swallowing with sensory testing (FEESST) offers a tool to further investigate the neural control of swallowing and airway protection.31Stimulation of the supraglottic mucosa induces a sequence of neurologic events that result in vocal fold closure and a subsequent swallow. Intact laryngopharyngeal sensation is necessary to protect the airway from aspiration, and this protection is mediated through the laryngeal adductor reflex (LAR).
Figure 12.3 Laryngoscopic view of the larynx of a toddler with Opitz G-BBB syndrome and chronic aspiration of liquids. Wide interarytenoid distance and redundant mucosa suggested the presence of laryngeal cleft, which was confirmed by palpation.
Image courtesy: David E. Tunkel, M.D.
FEEST was developed as a precise method of assessing laryngopharyngeal sensation. In infants and children, this is assessed by administering an air pulse calibrated for duration and intensity (ranging from 2.5 to 10 mm Hg) to the aryepiglottic fold region, and observing the induction of a swallow, a cough, or vocal fold closure. The stimulation threshold required to induce the LAR should be determined for each side of the larynx. A sensory threshold greater than 4.5 mm Hg strongly correlates with a positive history of aspiration pneumonia. There is a strong correlation in children with laryngomalacia and GERD. Feeding problems are also common in this group. Sensory thresholds within the larynx on FEEST are elevated in these children, with the thresholds normalizing and the swallowing problems resolving after treatment with antireflux medications.32
Nuclear Medicine Scans
Nuclear medicine scans may be used in the assessment of gastric emptying and gastroesophageal reflux. They are also used as a tool for demonstrating aspiration of oral secretions.
Technetium scans are useful in the evaluation of children with gastric motility problems. Technetium is mixed with familiar food and administered to the patient. Frequent images are then obtained by a gamma camera for 1 hour; delayed images are obtained for up to 24 hours. Reflux events can be demonstrated by identifying labeled material in the esophagus. The reflux event may deposit gastric contents into the hypopharynx, where it can be cleared through normal pharyngeal contractions or aspirated. The amount of material collecting in the airway is then quantified.
Intravenously injected thallium, which is concentrated in the functioning salivary gland tissues, is excreted into the mouth with saliva. This can be used to quantify oral secretions aspirated over time. Images of labeled secretions are obtained with a gamma camera. In normal studies, the label is found in the salivary glands and stomach, with low levels in the oral cavity, pharynx, and esophagus. In children who aspirate oral secretions, label is also seen throughout the lung fields. A thallium scan is useful in determining the need for surgical intervention to prevent chronic, life-threatening pulmonary disease.
Management decisions for infants and children with feeding and swallowing problems should be made only after a detailed medical history, clinical feeding observations, and a thorough diagnostic assessment. In the setting of complex medical and developmental conditions, decisions are best made through a multidisciplinary team approach. The treating clinician must have a clear understanding of the interplay between anatomic abnormalities, medical conditions, the level of functioning, and behavioral factors.
The goal of treatment is to maximize each child's nutritional status in the context of safe and efficient feeding.33 This frequently involves modifications in the volume, consistency, texture, or temperature of foods and liquids; the use of adaptive oral feeding utensils or equipment (e.g., bottle nipples with varying size, shape, and flow rates) to increase liquid tolerance; or repositioning the head and body to allow for better airway protection or more efficient passage of a food bolus through the oropharynx. For example, tilting the head forward widens the vallecular space, thereby diverting food away from the laryngeal inlet. When appropriate, parents or caregivers also may be provided with exercises to strengthen or improve the coordination of weak muscles of the child's face, tongue, lips, and palate. In patients with a tracheotomy there is a loss of normal subglottic pressure, which may interfere with airway protection. Capping the tracheotomy or placing a speaking valve onto the tracheotomy can normalize this pressure.
Children with psychosocial or behavioral components associated with their dysphagia are generally responsive to behavior therapy. A structured therapeutic program includes techniques such as rewarding successive approximations of targeted behaviors and offering positive reinforcement through praise, access to favorite toys or music, clapping, or any similar age-appropriate reward. Optimally, the gradual advancement of rewarded goals eventually leads to full oral feeding. Behavior therapy is also used to overcome conditioned food refusal (i.e., a learned aversion to feeding) associated with a previous anatomic abnormality that has been corrected.
For many children with neurologic or anatomic abnormalities, safe oral feeding is extremely difficult or impossible. Deciding whether to pursue efforts at oral feeding requires judicious consideration of the potential risks of aspiration and chronic lung disease versus the convenience and emotional rewards of oral feeding. Supplementing a child's nutrition by nasogastric or gastrostomy feedings may be either essential or prudent in terms of the child's overall development and well-being.
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