Key points

Overview

Swallowing disorders are of many different causes and may lead to significant morbidity and mortality if not addressed. These disorders affect patients of all ages; however, their prevalence increases in the elderly population, not because of the normal aging process but rather the fact that, as patients age, they are more likely to be affected by disorders that lead to dysphagia such as stroke and neurodegenerative disorders. Dysphagia has been associated with increased incidence of malnutrition, aspiration pneumonia, and death, especially in the elderly population. Due to this, aggressive management of swallowing disorders is essential to limit their associated morbidity and mortality. Treatments of swallowing disorders either address the underlying cause of the patient’s dysphagia or aim to decrease the incidence of dysphagia-associated complications. Although medical and surgical therapies have been the mainstays of managing these patients, complementary and integrative medicine approaches have also been described and may play a role in treatment of swallowing disorders.

Overview

Swallowing disorders are of many different causes and may lead to significant morbidity and mortality if not addressed. These disorders affect patients of all ages; however, their prevalence increases in the elderly population, not because of the normal aging process but rather the fact that, as patients age, they are more likely to be affected by disorders that lead to dysphagia such as stroke and neurodegenerative disorders. Dysphagia has been associated with increased incidence of malnutrition, aspiration pneumonia, and death, especially in the elderly population. Due to this, aggressive management of swallowing disorders is essential to limit their associated morbidity and mortality. Treatments of swallowing disorders either address the underlying cause of the patient’s dysphagia or aim to decrease the incidence of dysphagia-associated complications. Although medical and surgical therapies have been the mainstays of managing these patients, complementary and integrative medicine approaches have also been described and may play a role in treatment of swallowing disorders.

Physiology and anatomy

The upper aerodigestive tract participates in swallowing, and normal swallowing has phases under volitional and reflexive control. Structures involved in swallowing are located in the oral cavity, oropharynx, larynx, and esophagus ( Fig. 1 ). The upper aerodigestive tract has been described as a series of 6 valves. These valves include

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  Lips

  
  
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  Tongue

  
  
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  Glossopalatal valve

  
  
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  Velopharyngeal valve

  
  
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  Larynx

  
  
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  Cricopharyngeal sphincter

Normal anatomy and physiology of swallowing. ( A ) Oral phase, ( B ) pharyngeal phase, and ( C ) esophageal phase.

( Courtesy of M. Gallagher, MS, Chicago, Illinois.)

At the initiation of feeding, the lips, via the orbicularis oris muscle, form the first valve by forming a seal around the eating utensil. This valve also contributes to oral competence during mastication.

Next, the tongue acts as the second valve, moving food around the mouth permitting mastication, intermixing of saliva produced by the salivary glands, and finally, forming a bolus of food to begin the oral phase of deglutition. At the same time, the buccinator muscles act to hold the cheeks to the alveolar ridges to prevent food from being displaced into the lateral sulci during mastication. The soft palate, which acts as the third (glossopalatal) valve, makes contact with the back of the tongue to prevent the bolus from prematurely entering the oropharynx. The oral phase of the swallow is then initiated when the tongue makes contact with the hard palate in an anterior to posterior direction, allowing the bolus to be transported to the oropharynx.

When the bolus reaches the faucial arches, the pharyngeal swallow is triggered. From this point forward, the swallow is no longer under voluntary control. During the pharyngeal phase, the base of tongue moves posteriorly to contact the posterior pharyngeal wall, thus pushing the bolus inferiorly. At the same time, the fourth (velopharyngeal) valve closes to prevent reflux of material into the nasopharynx. Next, the larynx acts as the fifth valve protecting the airway with the approximation of the true and false vocal cords. In addition, the larynx and hyoid bone elevate, which causes the epiglottis to fold down over the airway providing additional protection. Finally, the bolus reaches the cricopharyngeal valve (upper esophageal sphincter). This valve relaxes, and food can pass into the esophagus and then into the stomach via peristalsis.

Symptoms

Swallowing disorders have many different causes, and symptoms vary with each underlying cause. These disorders are grouped into 2 categories based on the location of the dysfunction:

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  Oropharyngeal

  
  
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  Esophageal

Oropharyngeal dysphagia is further categorized into neuromuscular and structural causes. Similarly, esophageal dysphagia is categorized as either esophageal dysmotility or structural esophageal dysphagia. Understanding the different symptoms associated with each underlying cause of dysphagia can help the physician pinpoint the cause of the swallowing disorder and can direct further management.

Dysphagia of all causes may present with malnutrition and weight loss. One study found a statistically significant increase in malnutrition in patients with oropharyngeal dysphagia compared with patients without, as determined by the mini nutritional assessment. Similarly, in a study by Caporali, 160 patients with systemic sclerosis were studied for malnutrition, as defined by body mass index less than 20 or a 6-month weight loss greater than 10% and determined that 15% of these patients had evidence of malnutrition according to this criterion. Malnutrition, however, is very nonspecific and does not suggest the etiology of the underlying cause.

Oropharyngeal dysphagia is distinguished from esophageal dysphagia by symptoms involving structures above the esophageal inlet. The patient with oropharyngeal dysphagia may present with recurrent aspiration pneumonia or frequent cough after swallowing. If residual food is present in the vallecula after swallowing, the patient may note the need to swallow multiple times to clear the bolus. Further determination of timing of symptom onset and associated symptoms helps further delineate the underlying cause of oropharyngeal dysphagia.

Oropharyngeal dysphagia can further be categorized according to whether it has

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  Neuromuscular cause

  
  
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  Structural cause

The most common neuromuscular cause of dysphagia is stroke, with 25% to 40% of stroke patients experiencing dysphagia. About 45% to 68% of patients with dysphagia after stroke die within 6 months, and this death rate is largely attributed to malnutrition and aspiration pneumonia. In patients with oropharyngeal dysphagia due to stroke, symptoms of dysphagia are acute in onset and are associated with other stigmata of stroke such as hemiparesis or bulbar symptoms.

As patients age, neurodegenerative diseases such as dementia and Parkinson disease become more prevalent. In one study, pneumonia was found to be the cause of death in 55% and 33% of patients with Alzheimer and vascular dementia, respectively. Similarly, in patients with Parkinson disease, the median duration between dysphagia onset and death is 15 to 24 months. Dysphagia in both dementia and Parkinson disease is often slow and progressive in nature. On esophageal manometry, patients with Parkinson frequently have diminished cricopharyngeal relaxation.

Patients with other, less common, neuromuscular diseases may also present with symptoms of dysphagia. Dysarthria and dysphagia are the presenting complaints in 25% to 30% of patients with amyotrophic lateral sclerosis. These patients note symptoms that are gradual in onset and are associated with focal areas of weakness. Physical examination of these patients frequently reveals fasciculations of the tongue. Dysphagia affects 30% to 60% of patients with polymyositis and dermatomyositis. Patients with these inflammatory myopathies present gradual onset dysphagia with proximal limb weakness. Patients with dermatomyositis also have skin manifestations such as the heliotrope rash. Patients with myasthenia gravis may also present with dysphagia, which may wax and wane and increase in magnitude with fatigue.

In contrast to neuromuscular causes, structural anomalies are also associated with oropharyngeal dysphagia. Patients with Zenker diverticulum complain of dysphagia that is gradual in onset. If food falls into the diverticulum, the patient may complain of regurgitation of undigested food or may even present with symptoms of aspiration. As the pouch enlarges over time, it may lead to extrinsic compression of the esophagus and further dysphagia, especially to solid foods.

Another structural cause of oropharyngeal dysphagia is secondary to head and neck neoplasm. Dysphagia may be due to tethering of the tongue, abnormal pharyngeal wall motion, or obstruction of the esophageal inlet. Although less common, it is also possible for masses outside the aerodigestive tract, such as large thyroid neoplasms, to cause extrinsic compression leading to dysphagia. Patients can often develop dysphagia following medical and surgical treatment of head and neck cancer. For instance, surgical resection of oral and oropharyngeal tumors historically resulted in poor swallowing outcomes, but swallowing function after these surgeries has improved with the advent of free flap reconstruction. Combined chemotherapy and radiation has been associated with swallowing impairment with 50% of patients having long-term dysphagia and 70% having xerostomia. In a study by El-Deiry, surgical resection with postoperative radiation had a similar degree of swallowing dysfunction as combined chemotherapy and radiation.

The symptomatic presentation of esophageal dysphagia can differ from that of oropharyngeal dysphagia. Patients with esophageal dysphagia often note a sensation of food getting “stuck” several seconds after swallowing and frequently localize the sensation to an area deep to the sternum. Because patients with esophageal dysphagia occasionally have referred sensation in the neck, care must be taken when relying on these symptoms for localization.

Similar to oropharyngeal dysphagia, esophageal dysphagia is divided into 2 main underlying causes:

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  Structural causes

  
  
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  Esophageal dysmotility

Structural causes present with gradual onset of dysphagia to solids before liquids. Some examples include esophageal strictures, rings, webs, or malignancy. In contrast, patients with esophageal dysmotility present with dysphagia to both solids and liquids. Symptoms that are intermittent in nature suggest diffuse esophageal spasm as the underlying cause of dysmotility whereas constant, progressive symptoms point to achalasia or scleroderma.

Furthermore, swallowing disorders in the pediatric population can have different presentations and causes as compared with adults. Common symptoms in this population include poor coordination of the suck-swallow-breathe reflex, coughing while feeding, drooling, failure to thrive, and prolonged feeding times. Dysphagia and feeding difficulties are also prevalent in prematurity. In one study, patients with prematurity-associated bronchopulmonary dysplasia were found to have poor suck-swallow-breathe coordination, weak sucking pressures, less frequent swallowing, and prolonged deglutition apnea. Other common disorders associated with pediatric dysphagia are neuromuscular diseases such as cerebral palsy and spinal muscular atrophy type II, laryngomalacia, vocal cord paralysis, and vascular rings/slings.

Although eosinophilic esophagitis, an entity associated with swallowing dysfunction, is typically diagnosed in childhood, it can present in patients of any age. Symptoms can vary depending upon age. Presentation during infancy includes vomiting, food refusal, and choking with meals. On the other hand, dysphagia, food impaction, gagging with meals, and occasionally chest pain are symptoms commonly encountered in older children and adolescents. Adults typically present with dysphagia, heartburn, and food impaction secondary to esophageal rings and webs. In patients of all ages, there is a lack of response to acid-reducing medications and an association with food and environmental allergy.

Medical treatment approaches and outcomes

Whenever possible, the primary goal of management of swallowing disorders should be to treat the underlying cause. In most types of oropharyngeal dysphagia of neuromuscular cause, treating the underlying cause does not improve dysphagia. In a meta-analysis of patients with Parkinson disease, treatment with levodopa did not improve swallowing dysfunction despite improvement in other symptoms. In contrast to other neuromuscular causes of oropharyngeal dysphagia, treatment of inflammatory myopathies has led to decreased symptoms of dysphagia. In 2 randomized controlled trials, patients with severe inflammatory myopathies demonstrated improvement in dysphagia when intravenous immunoglobulin was administered over several sessions. In a case series by Kiely, all 4 patients with severe dysphagia and a diagnosis of inflammatory myopathy who underwent intravenous immunoglobulin treatment became gastrostomy-tube independent after therapy.

In addition to medical therapies, nonsurgical, procedural treatments are available to address specific causes of dysphagia. In cases of dysphagia induced by late-stage, unresectable esophageal neoplasm, a statistically significant improvement in swallowing was found in patients undergoing esophageal stent placement. Botulinum toxin (Botox) injection has also been used to treat several types of dysphagia. In a study by Storr, endoscopic injection of Botox into the esophageal wall was performed on patients with diffuse esophageal spasm, resulting in an elimination of symptoms in 8 of 9 patients; this is in contrast to the traditional medical management with anticholinergics, nitrates, calcium channel antagonists, and antidepressants, in which clinical trials have shown mixed results regarding efficacy. Injection of Botox into the lower esophageal sphincter (LES) in patients with achalasia has demonstrated short-term resolution of symptoms in 78% to 90% of patients, but recurrence of symptoms is relatively common. Cricopharyngeus injection of Botox has been described, but outcomes remain better in patients undergoing surgical myotomy for cricopharyngeal dysfunction.

In cases where treatment of the underlying condition is not possible, management goals should be supportive, including decreasing symptoms of dysphagia and preventing aspiration. The most noninvasive means of doing so involves dietary modification (eg, thickening of liquids) and speech and swallow therapy. Speech and swallow therapy aims to strengthen weakened oropharyngeal muscle groups or to modify dysfunctional portions of the swallow apparatus to prevent aspiration. In a randomized controlled trial, there appeared to be no significant difference when comparing the chin-down technique during swallowing versus thickening of liquids. Because no randomized trials to date have included a nontreatment group, the true benefit of these interventions remains unknown. In the infant and young child, swallow therapy and transition to oral feedings differ slightly from that of the adult, with increased emphasis on oral stimulation and nonnutritive stimulation. These interventions have been associated with faster transition to oral feeding and shorter hospital stays in preterm infants.

When dietary modifications and swallow therapy alone are insufficient in preventing pneumonia, alternative means of feeding may be required. Nasogastric tube (NGT) feeding is a nonsurgical alternative to feeding via a percutaneous endoscopic gastrostomy (PEG) tube. Studies have compared feeding via NGT to that of PEG tube in stroke patients and have shown no difference in aspiration rates between either method. One benefit to PEG over NGT is that PEG was found to be superior to NGT with regards to delivering the prescribed number of calories and maintaining adequate long-term nutrition. On the other hand, PEG was associated with higher risk of death at 6 months when compared with NGT.

Surgical treatment approaches and outcomes

Similar to medical management, the initial goals of surgical management should be directed toward treatment of the underlying condition. In patients with Zenker diverticulum, treatment is surgical and may be approached with either an endoscopic or an open, transcervical approach. When endoscopic stapler-assisted esophago diverticulostomy was compared with open cricopharyngeal myotomy, endoscopic approaches have resulted in shorter operating duration, faster recovery, shorter time to oral intake, and shorter hospital stays. Both surgeries have similar success rates ranging from 90% to 100%. The major disadvantage of endoscopic stapler-assisted repair is the limited benefit in very small (<2 cm) diverticula where the anvil of the stapler is too long to fit in the pouch. Endoscopic carbon dioxide laser-assisted diverticulectomy has been studied; however, results are mixed when compared with stapler-assisted procedures.

In addition to patients with Zenker diverticulum, select patients with neuromuscular causes of oropharyngeal dysphagia may be candidates for cricopharyngeal myotomy. Parkinson disease and the inflammatory myopathies have been associated with dysfunction of the upper esophageal sphincter. Outcomes after cricopharyngeal myotomy in these patients are worse with published success rates of 60%.

There are various surgical interventions for the many causes of esophageal dysphagia. The surgical treatment of achalasia is laparoscopic Heller myotomy (LHM) with fundoplication. In one study, 90% of patients with achalasia who underwent LHM reported resolution of symptoms. Pneumatic dilation of the LES is also an alternative to surgery in these patients. In a multicenter, randomized controlled trial, there was no difference between the 2 procedures with respect to symptoms, LES pressure, esophageal emptying, and quality of life. The authors argue that balloon dilation carries a high risk of perforation even in experienced hands, and multiple dilation procedures must be performed to achieve the same result as LHM. In patients with esophageal cancer who have resectable disease, removal of the mass is the treatment of choice to improve the patient’s dysphagia. One common complication of Ivor-Lewis esophagectomy, however, is anastomotic stricture, with postoperative rates of dysphagia to solid foods quoted at 25% to 35%.

When PEG or NGT feeding fails to prevent aspiration events, more radical measures may be required to prevent aspiration, such as

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  Glottis closure

  
  
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  Laryngotracheal separation

  
  
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  Total laryngectomy

Most studies published in the literature have been small in scale and no prospective trails have been performed. Laryngotracheal separation is most commonly performed on the neurologically impaired pediatric patient; however, it also has been described as a treatment of the elderly patient with intractable aspiration. In a retrospective review of 56 neurologically impaired pediatric patients with intractable aspiration, laryngotracheal separation resulted in control of aspiration in 100% of patients.