Pediatrics

Dysphagia and Aspiration

OVERVIEW: What every practitioner needs to know

Are you sure your patient has dysphagia and aspiration? What are the typical findings for this disease?

The typical presentation of a patient with chronic aspiration is with recurrent pneumonia or chemical pneumonitis (See Figure 1). However, there is no pathognomonic symptom or classic constellation of symptoms that is specific or sensitive for the diagnosis of dysphagia and aspiration. It is also important to recognize that aspiration may occur entirely silently with the only symptoms and signs attributable to secondary airway or pulmonary parenchymal dysfunction.

Figure 1

Right upper lobe pneumonia and atelectasis in a child with Spinal Muscular Atrophy(SMA) type II

Young infants may present with laryngospasm, cyanotic spells or apnea; in these cases, aspiration may result in a diagnosis of sepsis or acute life threatening event. Infants and children may present with chronic chest or upper airway congestion, tachypnea and difficulty breathing. Difficulty with feeding and recurrent infections may lead to difficulties in achieving optimal weight gain. Over time, they may develop problems of oval aversion. Chronic nasal congestion and sinusitis may also result from nasopharyngeal reflux of gastric and oral contents.

The typical findings of dysphagia and aspiration include:

Chronic cough

Cough, choking or gagging with oral intake

Airway symptomatology including recurrent or chronic wheezing, stertor or stridor

Definition of key terms:

Direct Aspiration: Aspiration of oral contents into the tracheo-bronchial tree.

Gastroesophageal Reflux (GER): Movement of stomach acid/contents into the esophagus.

Gastroesophageal Reflux Disease (GERD): GER associated with symptoms or signs including, but not limited to dyspepsia, frequent belching, emesis, heartburn or the pathologic finding of esophagitis.

Extraesophageal Reflux (EER): The passage of refluxate from the esophagus into the upper and lower airways, nose, nasopharynx and oral cavity. Also referred to as Secondary or Retrograde Aspiration.

Extraesophageal Reflux Disease (EERD): Extraesophageal reflux secondarily results in another disease process, such as rhinosinusitis, pneumonia or asthma.

Silent Aspiration: Passage of food or liquid through or below the level of the true vocal cords without production of reflexive cough or other overt symptoms.

Pathophysiology of dysphagia and aspiration

Dysphagia is a descriptive term and is not instructive of a specific diagnosis. The clinical diagnoses of dysphagia and aspiration encompass a variety of maladaptive feeding and swallowing patterns. On the one hand, dysphagia and aspiration of food or liquid into the tracheobronchial tree is a common cause of respiratory symptoms. On the other hand, chronic cardiorespiratory, metabolic and neurologic diseases may result in dysphagia and aspiration through abnormal coordination between breathing and swallowing, alteration of pulmonary mechanics and ineffective cough clearance of aspirated material.

Complexity of swallowing:

Swallowing is a highly complex process which involves the coordinated effort of multiple cranial nerve and skeletal muscles as well as cervical and thoracic spinal cord segments. An intact swallow requires appropriate central pattern generation from motor neurons; it also is controlled by both reflexive and voluntary mechanisms and depends on sensory feedback for optimal function.

Stages of Swallowing

Oral phase: The oral phase is the only phase of swallowing under voluntary control. During this phase, a food bolus is ingested, masticated and propelled posteriorly into the pharynx. Swallowing is initiated by an elevation of the tongue which propels the bolus of food or liquid posteriorly. Pathology leading to dysphagia may be found in the oral phase and may include oral motor or sensory dysfunction (oral aversion).

Pharyngeal phase: In this phase, the pharyngeal swallow is initiated and the food bolus is transferred through the pharynx by pharyngeal constrictor musculature. A successful second stage of swallowing is achieved when there is superior and anterior displacement of the larynx and capping of the epiglottis over the larynx in order to protect the airway. Simultaneously, the nasopharynx is occluding by the soft palate and uvula. Airway closure is critically important in this phase to prevent aspiration. Functional motor and sensory units are needed to achieve this laryngeal protection.

Esophageal phase: The esophageal phase is indicated by relaxation of the superior esophageal sphincter. Peristaltic waves then propel the food bolus into the stomach. A dysfunctional esophageal phase may be secondary to neuropathy or esophageal disorders. Esophageal dysfunction, in turn, may be due to anatomic abnormalities or functional disorders.

Physiology of swallowing

Throughout life, the act of breathing is closely associated with the actions of drinking, eating and swallowing. Swallowing is a functional behavior that is dominant to breathing in normal individuals. Because of the higher respiratory rate associated with young age, swallowing must interrupt the breathing of infants and children. The pause in breathing during swallowing is referred to as deglutition apnea; it is only made possible when there is proper closure of the laryngeal airway and suppression of the brainstem based respiratory pattern generator. A normal and protected swallow, therefore, requires coordination between multiple physiologic processes.

A coordinated swallow is marked by the timing of the deglutition apnea. A swallow of a liquid bolus is generally initiated during the expiratory phase of breathing. In adults, 75-95% of swallows are initiated during this expiratory phase. Only 39% of newborns have a similar pattern. A newborn nutritive swallow occurs primarily at the inspiratory-expiratory cusp. Timing of a swallow in mid-expiration and at the expiratory-inspiratory transition are variants.

A post swallow expiration is an important marker of breath-swallow coordination from birth. Deviation from these swallowing patterns can result in a swallow that is considered as disordered or discoordinated.

Premature infants swallow predominantly during respiratory pauses. This timing represents a delicate balance that is easily overwhelmed by respiratory or cardiac compromise.

What other disease/condition shares some of these symptoms?

As the symptoms of dysphagia and aspiration are often non-specific, there are a great number of disease processes that may present with similar signs or symptoms.

Common diseases that may be "mimicked" by dysphagia and aspiration include the following (of note, many of these diseases or clinical problems may co-exist with and be exacerbated by dysphagia and aspiration):

Asthma

Bronchopulmonary Dysplasia

Laryngomalacia

Bronchiolitis

Tracheomalacia

Subglottic stenosis

Cystic Fibrosis

Tracheo-Esophageal Fistula

Pulmonary vascular ring or sling

Complex congenital heart disease

Sinusitis (acute or chronic)

Less Common/Rare:

Mediastinal Mass

Eosinophilic Esophagitis

Acute Life Threatening Event (ALTE)

Immunodeficiency related pulmonary disease

Collagen Vascular Disease

Systemic Sclerosis

Familial Dysautonomia

Globus Hystericus

Primary Ciliary Dyskinesia

Infectious Esophagitis

Mucosal Candidiasis

Achalasia

What caused this disease to develop at this time?

Owing to the wide spectrum and complexity of associated problems, etiologies for dysphagia and aspiration have classically been divided into several categories. These include structural abnormalities and chronic medical illness; medical diagnoses attributable to the cardiac and respiratory systems; genetic, neurologic, degenerative and metabolic disease are implicated as are oral sensory and behavioral disorders. There is often significant overlap between categories. Illustrating this point, Rommel et al investigated the etiology of dysphagia in 700 children. The mean age was 25 months. Nearly half of these patients had a multifactorial etiology for their dysfunctional feeding pattern.

Although occasional low grade aspiration of oral contents, particularly during sleep, can be a normal phenomenon, pulmonary disease is generally associated with a large volume of aspirated material. Alternatively, chronic aspiration of small volumes or a pre-existing lung injury such as chronic pulmonary inflammation may be responsible for overwhelming host defenses.

25%-45% of children will experience problems with feeding and swallowing. The prevalence of dysphagia and aspiration related disease has increased in the last 20 years, likely due to increased survival of very low birth weight infants and children with complex illnesses. When compared to adults, infants and children have increased vulnerability to aspiration due to structural differences in their airways and physiologic differences in respiratory patterns. However, they also have a better prognosis.

Prevalence is markedly increased in patients with neurologic compromise and developmental delay. Response to speech therapy in these patients is variable and dependent, at least in part, on the underlying neurologic dysfunction. Similarly, patients with severe muscular weakness (Spinal Muscular Atrophy types I and II, spinal cord injury) are at high risk for dysphagia and aspiration and are less likely to improve.

Patients with tracheostomy should receive special consideration as they have an altered laryngeal reflexes and an ineffective cough and are therefore more likely to aspirate and are at increased risk for aspiration-related conditions.

EERD is believed to begin in childhood and a genetic association has been mapped to chromosome 13q14 in some cases.

Development of the Child's Airway as it Relates to Swallowing Function

Anatomical and physiological factors increase the risk of dysphagia and aspiration in infants and small children, even without other predisposing structural defects or complicating medical conditions.

Physiologically, nutritive sucking can be expected to occur developmentally at 34 weeks gestation. The ability of an infant to feed orally is, in part, determined by the ability to non-nutritively suck in a coordinated manner. Young and premature infants, therefore, are at increased risk for dysphagia and aspiration.

Structurally, the larynx of an infant is anatomically more superior in the airway than that of an older child or adult. The location of the glottis is at the 4th cervical vertebrae in infants. It descends to the level of C5-C6 during adolescence and later to the adult position of C7. The epiglottis is also short and often omega shaped in the infant and child. This shape and size of the epiglottis may less effectively cap the larynx and protect the airway during swallowing.

Finally, newborns and young infants breathe more quickly and with less depth than older infants, children and adults. Therefore, the timing of breathing and swallowing need to be exquisitely well coordinated and leave little room for error.

Clinical Risk factors for Dysphagia and Direct Aspiration

As the number of potential contributing factors is large, risk factors for dysphagia and aspiration have, for the purposes of this chapter, been divided into four categories. These include developmental disorders, anatomic abnormalities, neurologic disease and acquired conditions.

Developmental Disorders

Prematurity:

Feeding and swallowing problems in this group are related to the frequent presence of co-morbid conditions including neurologic dysfunction, degree of prematurity and presence of respiratory compromise.

Fatigue Aspiration:

This is a special consideration in young children and in those with muscular or neurologic disease. Many infants will swallow normally or near-normally during the first few swallows but then demonstrate deterioration in their ability to maintain protection of the laryngeal airway during late feeding. The speech therapist or radiologist performing a swallow study should be informed if this is a concern in order to obtain imaging during late as well as early feeding.

Feeding and Swallowing discoordination of unclear etiology:

A subset of term infants without other risk factors (GER, anatomic abnormalities, neurologic compromise) will aspirate silently or overtly and have secondary pulmonary symptomatology. The response of these infants to therapy is typically good. Associated structural and medical conditions contributing to the abnormal swallow must be sought as this is a diagnosis of exclusion.

Anatonic abnormalities:

Cleft Palate

Tracheo-esophageal fistula

Laryngo-tracheal cleft

Laryngomalacia - severe laryngomalacia has been associated with increased work of breathing during feeding. The diagnosis of failure to thrive in association with laryngomalacia may be a major determinant in a decision to proceed with surgical management.

Micrognathia (Pierre Robin sequence)

Macroglossia (Beckwith Wiedemann syndrome)

Pulmonary Vascular ring or sling

Neurologic disease:

Spinal Muscular Atrophy - poor coordination between suck, swallow and respirations due to profound muscular weakness. Also with ineffective cough. Aspiration in these patients is more likely to be entirely silent.

Post asphyxia brain damage

Cerebral Palsy

Familial Dysautonomia

Myopathy

Acquired conditions:

Tracheostomy

Endotracheal intubation

Post operative vocal cord paresis (may be associated with repair of congenital heart lesions among others)

Chiari Malformation with vocal cord paralysis

Bronchopulmonary Dysplasia (BPD) - Mizuno et al have documented poor suck-swallow-breath coordination and weak sucking pressures as well as lengthened deglutition apnea in association with BPD. Extended periods of oxygen therapy have been associated with an increased risk of impairment in non-nutritive sucking.

Bronchiolitis

Pneumonia

The Association between GERD and Respiratory Symptoms

GER and respiratory symptoms are commonly encountered problems in clinical pediatrics. As such, it is often challenging to determine whether GER is causing the respiratory symptoms or if the two problems are merely co-existing.

It is known that nocturnal cough is predictive of proximal gastroesophageal reflux in patients with an incompetent lower esophageal sphincter (LES) diagnosed by manometry. As LES tone is not frequently measured in clinical medicine, it may be more applicable to consider the findings documented by Carr et all. They reported that the symptom most frequently encountered in children with documented GERD was chronic cough (51%). Other reported symptoms included nasal congestion (45%), frequent emesis (39%), hoarseness (34%), throat clearing (25%), dysphagia (24%), stertor and stridor (24% and 23% respectively).

From studies of pediatric patients with GER, it is known that patients < or = 2 years of age with GER are more likely to present with airway symptoms or feeding difficulty. In fact, limitation of airflow as seen with stertor, stridor or cyanotic spell, has a reported 88% PPV for reflux (as diagnosed by objective parameters) in children less than 2 years of age.

Conversely, patients > 2 years of age are more likely to present with symptomatology related to chronic airway irritation; these symptoms may include cough, recurrent croup or chronic throat clearing.

Clinical Risk Factors for EERD/Retrograde Aspiration

Chronic cough is associated with increases in intra-abdominal pressure and may increase the frequency and severity of GER through this mechanism. In turn, chronic GER may lead to edema of the posterior glottis with decreases in sensation and abnormal function of laryngeal protective reflexes.

Asthma is a commonly encountered clinical problem and may be exacerbated by gastroesophageal reflux and microaspiration. Significant cough may also be experienced by children with bronchopulmonary dysplasia, sinusitis and cystic fibrosis. Any condition associated with respiratory distress resulting in tachypnea or hyperinflation of lungs will also lead to increases in GER. It should be noted that many of the medications used for the treatment of asthma (including bronchodilators and theophylline analogs) have the unintended effect of lowering lower esophageal sphincter tone.

In children with tracheo-esophageal fistula, GER due to abnormalities in esophageal tone and neuromotor control may persist well after surgical repair of the fistulous lesion.

Abnormalities in muscular tone in the setting of Hypoxemic Ischemic Encephalopathy or other neurologic or muscular disease may affect gastric emptying and LES tone, thereby increasing the risk of gastro-esophageal reflux. In addition, these patients are likely to have a blunted laryngeal protective reflex.

In addition, patients with primary esophageal disorders such as eosinophilic esophagitis or achalasia may suffer from GER and be at risk for aspiration.

Aspiration Pneumonia and Pneumonitis

Mendelsohn's syndrome is a severe chemical pneumonitis that may occur following aspiration of stomach contents/refluxate.

Even in the absence of this named and severe syndrome, recurrent infiltrates may occur in patients with dysphagia.

Infiltrates, when present, are highly variable in severity and location. Non-specific radiographic findings such as hyperinflation or peribronchial cuffing may represent aspiration pneumonitis. Most importantly, wheezing, cough and chest congestion without radiographic findings may represent aspiration related illness in an "at risk" infant or child.

Physical Exam Findings associated with acute or chronic Aspiration

The physical exam findings associated with aspiration may be non-specific. Tachypnea is a common finding. Variable degrees of wheezing, inspiratory crackles, stridor or respiratory distress may be present. Hypoxemia may be documented.

What laboratory studies should you request to help confirm the diagnosis? How should you interpret the results?

While there are no laboratory studies specific for the diagnosis of dysphagia or aspiration, laboratory studies may be valuable in assessing the complications of dysphagia and aspiration. For example, a leukocytosis would be expected in a patient with aspiration pneumonia.

A multi-disciplinary approach to care is advantageous as it allows for a thorough evaluation of a child with feeding and swallowing dysfunction. Many health care disciplines, including pulmonary, ENT, Gastroenterology, OT, Psychology, Nutrition and Speech Pathology may be involved in the processes of evaluation and treatment.

The initial evaluation of a child with symptoms suggestive of dysphagia includes the observation and evaluation of feeding related oral motor skills. The coordination and safety of swallowing and oral nutrition can thereby be established. Cough, wheezing or upper airway congestion with feeding may suggest the need for further evaluations.

Would imaging studies be helpful? If so, which ones?

Videoflouroscopy (VFSS) - VFSS is the gold standard method of assessing swallowing function. Flouroscopy allows simultaneous visualization of all phases of swallowing. However, standardization of findings, including swallowing dynamics and severity assessments are not available. Interpretations and recommendations may vary between practitioners. Laryngeal penetration of the food bolus may be defined as shallow or deep. Aspiration may be qualified and quantified and responses to variations in bolus texture can be specified. The incidence of silent aspiration points to the importance of an objective study. There is exposure to radiation with a videoflouroscopic swallow study. Repeated studies should be entered into with consideration of risk versus benefit.

Upper Gastrointestinal Series or Modified Barium Swallow (UGI)- The barium swallow is an excellent study choice for determining the anatomy of the upper gastrointestinal tract. However, the sensitivity for aspiration disorders is low as are the sensitivity and specificity for clinically significant gastroesophageal reflux disease.

Radionucleotide "milk" scan - A study in which milk, containing a radiolabeled isotope, is ingested. Delayed radiographic images are then obtained to determine if tracer is visible in the airways or lungs. This testing has high specificity but low sensitivity for aspiration.

Other evaluations for Dysphagia and Aspiration:

Functional Endoscopic Evaluation of Swallowing (FEES) - A study in which an endoscope is utilized, generally by an Otolaryngologist, to directly observe the hypopharynx during swallowing. A green dye in the oral bolus is generally used so that passage of the food or liquid toward or past the vocal cords may be documented visually. This study is performed with an awake patient so as to allow cooperation with swallowing requests. Reliability is very good as compared to the gold standard of VFSS. There is no radiation exposure. The cost is inclusive of the procedure and the physician's time commitment.

Videomanometry - A combination of manometry and videoflouroscopy. Provides objective measurements of oropharyngeal transit time, pharyngeal contractile duration and UES function.

Bronchoscopy and Laryngoscopy - Laryngoscopy may reveal swelling of the peri-glottic tissues. Tracheal bronchi may demonstrate pallor, erythema, cobblestoning, increased secretions and tissue friability. A Lipid Laden Alveolar Macrophage Index (LLAM) > 100 is highly sensitive (100%) and moderately specific (57%) for aspiration related pulmonary disease. An Airway pepsin measurement is a newly available addition for the assessment of aspiration. As a gastric enzyme, it should not be found in airway secretions.

Newer and experimental testing modalities include:

Motor Evoked Potentials (MEPs) - signals are recorded from pharyngeal and submental musculature during rest.

Expected clinical application is to assess effects of dysphagia therapies on the neural pathways of swallowing.

Pharyngo-UES-esophageal micromanometry - measures reflexes related to swallowing and primary peristaltic waves.

Functional MRI - a pilot study and initial report exists regarding functional mapping of the brainstem based swallowing centers.

Electromyography - Ruark et al describe differences in muscle activity magnitude and duration, as measured by electromyographic measurements from the upper and lower lip, submental muscle and laryngeal strap musculature, as a function of bolus consistencies.

Confirming the diagnosis

There are no clinical decision algorithms currently available for the diagnosis of dysphagia and aspiration. The diagnosis is largely a clinical one. Based on the clinical suspicion, further testing, including the bedside clinical evaluation and VFSS may be considered as outined above.

If you are able to confirm that the patient has dysphagia and aspiration, what treatment should be initiated?

Alteration of bolus flow

Typically achieved by thickening the consistency of liquids. An early and common management strategy of patients with dysphagia. The intended effect is promotion of airway protection during swallowing. The characteristics of bolus flow and the effects of alteration in bolus consistency on swallowing are unknown. There is considerable variability across institutions in recommendations for thickening of feedings. Much of this approach is anecdotal.

Speech Therapy and Oral Motor Exercises

Active exercises include range of motion, stretching and strength training. The intended effect is to increase strength and endurance in nutritive and non-nutritive sucking. Passive exercises are also used and include massage, oral motor stimulation and passive range of motion exercises.

Naso-Gastric tube placement for primary nutrition

This is generally performed when the patient is found to be at risk for aspiration despite alteration of the food bolus. NG placement is generally well tolerated after an initial period of adjustment. After a period of training, this therapy can be managed independently at home in most cases.

Naso-Jejunal tube placement for primary nutrition

An NJ tube must be placed and replaced (in the event of tube displacement) by Interventional Radiology to confirm proper positioning past the pylorus. There is some risk of intestinal perforation (due to a weighted tube end) in younger infants. This therapeutic step may be necessary and useful in the setting of severe GERD and aspiration.

Gastrostomy Tube placement

A gastrostomy tube or button may be placed with or without Nissen fundoplication for severe or refractory GERD. Gastro-Jejunostomy Tubes may be useful in severe GER but their utility is often limited by frequent displacement and requirement for IR guided revisions.

Nissen Fundoplication

A surgical intervention designed to tighten an incompetent lower esophageal sphincter. Potential complications include but are not limited to chronic retching and long-term incompetence of the Nissen "wrap".

Jejunostomy Tube placement

This is a step that is infrequently required but represents a management option for patients with severe esophageal dysmotility or contraindications for Nissen fundoplication.

Laryngo-Tracheal Separation

This constitutes the most aggressive surgical option for the management of refractory direct aspiration and retrograde aspiration. The anatomic separation of trachea from larynx makes aspiration of contents into the tracheobronchial tree impossible. Tracheostomy placement is required. Patients will not be able to vocalize after the procedure.

Long term treatment depends on response to initial therapeutic interventions. In addition, treatment of the underlying condition is necessary for long term resolution. In cases where the underlying medical co-morbidity is not able to be treated or controlled, more aggressive management is required.

What causes this disease and how frequent is it?

As previously outlined, the etiologies of dysphagia and aspiration are diverse and may be multifactorial. The treatment options and efficacy, outcomes and prevention strategies are specific to the underlying pathophysiology of the co-morbidities.

What complications might you expect from the disease or treatment of the disease?

Children who require prolonged supplementation of nutrition with tube feedings often face difficulty on attempting to return to oral feeds. The reasons for this difficulty include disruption of the normal hunger-satiety cycle and the development of oral aversion or oral motor dysfunction.

Behavioral based treatment approaches have been shown to be effective in some cases but no treatment approach has been shown to be effective in all patients transitioning from tube to oral feeding. As such, a multidisciplinary team is beneficial in planning and executing treatment plans.

How can dysphagia and aspiration be prevented?

There are no known preventive strategies for idiopathic dysphagia and aspiration disorders. Early recognition and effective treatment/management of co-morbid conditions, where possible, can limit the severity and chronicity of dysphagia and aspiration syndromes.

What is the evidence?

Miller, CK. "Updates on Pediatric Feeding and Swallowing Problems". Curr Opin Otolaryngol Head Neck Surg. vol. 17. 2009. pp. 194-9.

Arvedson, J, Clark, H, Lazarus, C. "The effects of oral-motor exercises on swallowing in children: an evidence based systematic review". Developmental Medicine and Child Neurology. vol. 52. 2010. pp. 1000-1013.

Miller, CK, Willging, JP. "Advances in the evaluation and management of pediatric dysphagia". Curr Opin Otolaryngol Head Neck Surg. vol. 11. 2003. pp. 442-446.

Barlow, SM. "Central pattern generation involved in oral and respiratory control for feeding in the term infant". Curr Opin Otolaryngol Head Neck Surg. vol. 17. 2009. pp. 187-193.

Brodsky, L, Carr, MM. "Extraesophageal reflux in children". Curr Opin Otolaryngol Head Neck Surg. vol. 14. 2006. pp. 387-392.

Kovesi, T, Rubin, S. "Long term complications of Congenital Esophageal Atresia and/or Tracheoesophageal Fistula". Chest. vol. 126. 2004. pp. 915-25.

Rommel, N, DeMeyer, A, Feenstra, L. "The complexity of feeding problems in 700 infants and children presenting to a tertiary care institution". J Pediatr Gastroenterol Nutr. vol. 37. 2003. pp. 75-84.

Carr, MM, Nguyen, A, Nagy, M. "Clinical presentation as a guide to the identification of GERD in children". Int J Pediatr Otorhinolaryngol. vol. 54. 2000. pp. 27-32.

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