Dysphagia is a disruption in the ability to move food or liquid from the mouth through the pharynx and esophagus into the stomach safely and efficiently. Swallowing disorders can occur at any point in the life span from infancy through old age. It is estimated that approximately 6,228,000 Americans over age 60 have dysphagia, and that it occurs in 32% of all patients in intensive care units. If untreated, dysphagia can result in dehydration, weight loss, malnutrition, pneumonia, and, in rare cases, death.
In order to understand dysphagia, it helps to understand the normal swallow. A normal swallow rapidly carries a bolus of food or liquid through the mouth, pharynx, and esophagus, leaving these structures substantially clear of residue at its completion. It involves a complex interaction of sensory stimuli and motor responses that encompass both voluntary and involuntary behaviors.
A normal swallow consists of four phases: the oral preparatory phase, the oral phase, the pharyngeal phase, and the esophageal phase.
The oral preparatory phase readies the food or liquid for swallowing. The lips close and seal to contain the material in the mouth. Solid food is chewed and mixed with saliva. The tongue gathers the liquid or solid material into a bolus and holds it. During this phase, the entry into the airway is open and nasalbreathing continues.
The oral phase begins when the tongue starts to move the bolus backward toward the pharynx. It ends when the head of the bolus passes into the pharynx.
The pharyngeal phase begins when the bolus enters the pharynx and ends when it passes into the esophagus. In this phase, sensory stimuli interact with reflex and volitional movements to trigger the swallow response, which includes:
elevation and retraction of the soft palate to prevent material from entering the nose
elevation and forward movement of the hyoid and larynx, which moves them out of the path of the bolus as it travels downward, thus helping to prevent it from entering the airway below
closure of the larynx, which stops respiration momentarily and prevents the bolus from entering the airway below
retraction of the tongue base and contraction of the posterior pharyngeal wall, which build pressure to propel the bolus downward
progressive top to bottom contraction of the pharyngeal constrictor muscles, placing additional downward pressure on the bolus
opening of the pharyngoesophageal segment to allow the bolus to pass into the esophagus
The esophageal phase of the swallow begins when the bolus enters the esophagus and ends when it passes into the stomach. Muscular contractions push the bolus downward through the lower esophageal sphincter into the stomach.
Causes
Dysphagia occurs when any element of the normal swallow is disrupted. Oral structural abnormalities, muscular weakness, or incoordination may interfere with holding material in the mouth, forming it into a cohesive bolus, and propelling it backward into the pharynx. Lack of control over the material in the mouth might cause it to fall over the back of the tongue prematurely, while the airway is unprotected, or it might result in material remaining in the mouth after the swallow, when it could fall into the pharynx. If the bolus enters the pharynx before or after the swallow, while the airway is open and unprotected, there is a danger that aspiration will occur. Similarly, structural abnormalities, weakness, or incoordination in the pharynx or larynx may interfere with protection of the airway during the swallow or with the downward propulsion and emptying of the bolus into the esophagus. Finally, structural abnormalities, weakness, or incoordination in the esophagus may interfere with the progress of the bolus through the esophagus into the stomach.
Medications may also cause or exacerbate dysphagia. Antipsychotic drugs that cause extrapyramidal symptoms like tardive dyskinesia may cause dysphagia, and some anticholinergic drugs may impair swallowing ability.
Symptoms
Common symptoms of dysphagia include:
inability to control food or saliva in the mouth
residue in the mouth after the swallow
coughing during or after the swallow
gurgly or wet vocal quality associated with swallowing
Diagnosis of dysphagia generally involves a clinical screening evaluation (sometimes called a bedside evaluation) and an instrumental evaluation. The clinical screening evaluation includes review of the medical history; current medical status; examination of oral anatomy and oral motor functioning; perceptual evaluation of laryngeal functioning; and observation of eating and drinking unless the risk of aspiration is very high and the individual is deemed too medically fragile to tolerate it. If the clinical screening evaluation suggests the presence of a dysphagia, it is usually followed by an instrumental evaluation.
The instrumental evaluation that is most widely used for diagnosing oropharyngeal dysphagia is the videofluoroscopic modified barium swallow (MBS) study. The MBS study allows the observation of structures and movements as the individual swallows controlled amounts of various consistencies (usually thin and thick liquid, a paste or pudding consistency, and solid food) while seated in an upright position. It provides information about transit times through the mouth and pharynx, motility problems, and the presence and etiology of aspiration. The MBS is done in the radiology department and requires the patient's cooperation. Thus, it may be contraindicated for patients who are unable to cooperate with instructions, or who are too medically fragile to be transported.
Videoendoscopy, or flexible fiberoptic examination of swallowing (FEES), is another procedure used to examine for oropharyngeal dysphagia. A flexible scope is inserted through the nose into the pharynx, allowing observation of the pharynx before and after the pharyngeal swallow is triggered. It does not allow observation of the oral or esophageal phases of the swallow, and, because the image is blocked by the constriction of the pharynx around the scope during the pharyngeal swallow, the presence and etiology of aspiration may be inferred but cannot be observed. This procedure can be done at the bedside and requires minimal cooperation from the patient, making it useful for patients who cannot tolerate an MBS study.
KEY TERMS
Achalasia—Failure of the pharyngoesophageal segment to relax sufficiently to allow swallowed material to pass from the esophagus into the stomach.
Anterior faucial arches—Also called the glossopalatine arches, these pillar-like structures run from the palate down to the tongue laterally in the back of the mouth.
Anticholinergic drugs—Drugs that affect the parasympathetic system.
Aspiration—Entry of food or liquid into the airway below the level of the true vocal folds. Aspiration of large amounts or of small amounts over a period of time may result in pneumonia.
Cervical auscultation—Listening to the sounds of swallowing, usually via a stethoscope.
Dilatation—The stretching of a structure by swallowing increasingly larger sized rubber catheters filled with mercury.
Electromyography—Measures the timing and amplitude of selected muscle contractions.
Esophageal stenosis—Narrowing of the esophagus.
Esophagus—The tube that carries food or liquid from the pharynx to the stomach.
Globus—The feeling that there is a lump in the throat.
Hyoid—A small bone at the root of the tongue to which many lingual muscles are attached. It provides a stable base for tongue movement.
Larynx—Commonly called the voice box, this structure of muscle and cartilage sits at the top of the trachea.
Manometry—Measures of pressure changes that occur in the pharynx and/or esophagus during the swallow.
Motility—Movement.
Pharyngoesophageal segment—Also called the cricopharyngeal muscle or the upper esophageal sphincter (UES), this segment is normally in tonic contraction in awake individuals to prevent air from entering the esophagus during respiration and to reduce the risk of reflux from the pharynx into the esophagus.
Pharynx—The hollow muscular tube, commonly called the throat, that runs from the base of the skull to the opening of the esophagus.
Scintigraphy—A nuclear medicine test requiring the patient to swallow measured amounts of radioactive substance. It can reveal the amount of aspiration and residue, but does not allow visualization of structures or movements.
Tardive dyskinesia—A disorder characterized by abnormal involuntary movements.
The instrumental evaluation most frequently used for esophageal dysphagia is the standard barium swallow or upper gastrointestinal series. This differs from the MBS study in that the patient is required to swallow a much larger amount of barium, typically while lying in the prone position. It allows observation of structures and of the movement of the material through the esophagus and into the stomach. When gastroesophageal reflux disease is suspected, continuous pH monitoring that measures the pH level of the contents of the lower esophagus is considered the best single test for its diagnosis.
Other instrumental evaluations that are sometimes used, either alone or in combination with the more standard techniques, include: ultrasound of the oral cavity, scintigraphy, electromyography, cervical auscultation, and manometry.
Treatment
Treatment of oropharyngeal dysphagia depends on the etiology and the severity of the problem. An essential component of treatment is education of the patient, family, and other caregivers regarding the nature of the swallowing problem, its potential complications, and the importance of following recommendations to prevent such complications. Treatment may also involve one or more of the following:
An exercise program to improve the strength, range of motion, speed, and/or coordination of movements.
Diet modifications that eliminate food or liquids of consistencies that are at high risk of being aspirated.
Teaching of specific postures or strategies designed to reduce or eliminate the risk of aspiration when swallowing.
Use of an alternate means of feeding, such as a gastric tube, either temporarily while other treatment strategies are attempted, or permanently if other treatment is unsuccessful.
Esophageal dysphagia is usually medically, rather than behaviorally, managed. Dilatation is the typical treatment for esophageal stenosis. Surgery is most often used for esophageal tumors. Medications are used to treat motility disorders. Achalasia may be treated with smooth muscle relaxant drugs, dilatation, or surgery. Gastroesophageal reflux disease may be managed through dietary and lifestyle modifications, specifically: decreasing or eliminating certain foods from the diet, elevating the head of the bed for sleeping, avoiding lying down within two hours of eating, and eliminating smoking. Drugs and surgery are also used to treat this disorder.
Prognosis
The prognosis for recovery from dysphagia varies from excellent to poor depending on its severity, etiology, and the ability of the individual to comply with treatment recommendations.
Health care team roles
Identification, diagnosis, and management of dysphagia is a multidisciplinary effort. In most settings, speech-language pathologists perform screening evaluations, collaborate with a physician (usually a radiologist or otolaryngologist) in instrumental evaluations, design and implement a treatment program for oropharyngeal dysphagia, and provide education to the patient, family, and other staff members. The dietitian monitors the patient's nutritional status. The nursing staff, often the first to recognize dysphagic symptoms, encourages daily compliance with the recommended treatment program. Occupational and physical therapists work on feeding, adaptive devices, and sitting balance. (In some settings an occupational therapist is the primary swallowing therapist.) Physicians monitor and treat the patient's overall medical status. They are typically the primary treatment providers for esophageal dysphagia.
Prevention
Prevention of dysphagia requires prevention of the conditions that cause dyphagia, such as stroke, head trauma, or head and neck cancer. Prevention of complications from dysphagia involves adherence to the individualized treatment program, which usually specifies the precautions that should be taken. Although these will vary for each individual, they generally include eating and drinking only those foods and liquids of the recommended consistencies, sitting upright for oral intake, taking small amounts at a slow rate, ensuring that the mouth is clear after a swallow and at the end of a meal, using recommended strategies on every swallow, maintaining good oral hygiene, and remaining upright for 30 minutes after eating or longer if there is an esophageal dysphagia.
BOOKS
Johnson, Alex F. and Jacobson, Barbara H. Medical Speech-Language Pathology: A Practitioner's Guide. New York: Thieme, 1998.
Logemann, Jeri A. Evaluation and Treatment of Swallowing Disorders 2nd ed. Austin: Pro-ed, 1998.
PERIODICALS
Zorowitz, Richard D. and K. Robinson. "Pathophysiology of Dysphagia and Aspiration." Topics in Stroke Rehabilitation 6, no. 3 (Fall 1999): 1-16.
ORGANIZATIONS
American Speech Language Hearing Association. 10801 Rockville Pk., Rockville, MD 20852. (888) 321-ASHA. <http://www.als.uiuc.edu/drs/>.
Agency for Health Care Policy and Research. Diagnosis and Treatment of Swallowing Disorders (Dysphagia) in Acute-Care Stroke Patients: Evidence Report/Technology Assessment Number 8. Rockville, MD: U.S. Department of Health and Human Services, July 1999.
