Swallowing Problems (Dysphagia)

How We Swallow

The process of swallowing occurs sequentially:
Oral preparation phase, in which food or liquid (the bolus) is chewed or manipulated in preparation for swallowing.
Oral propulsive phase, in which the tongue pushes the food or liquid to the back of the mouth, beginning the swallowing response.
Pharyngeal phase, in which food or liquid quickly passes through the pharynx (the canal from the mouth to the esophagus) into the esophagus
Esophageal phase, in which the food or liquid moves through the esophagus into the stomach.

The first two phases are controlled voluntarily, while the latter two occur involuntarily. The process involves rapid, precise coordination of numerous muscles and tissues of the mouth, pharynx, larynx and esophagus. When the bolus (food or liquid) enters the pharyx, the soft palate elevates and the hyoid bone and larynx move upward and forward. The vocal folds move to the midline and the epiglottis folds backward, protecting the airway. The tongue pushes backward and downward into the pharynx, pushing the bolus down. The pharyngeal walls assist this process by moving inward with a progressive wave of contractions from top to bottom. The upper esophageal sphincter relaxes and is pulled open by the movement of the hyoid bone and larynx, and then the sphincter closes after the food passes. Once in the esophagus, a peristaltic wave moves the food downward. The lower esophageal sphincter relaxes and allows the bolus to move into the stomach. After the food is in the stomach, this lower sphincter closes automatically, preventing gastroesophageal reflux.

What Causes Swallowing Problems?

Interruptions in this process can cause difficulty in swallowing, or dysphagia. A number of conditions may cause dysphagia, including mechanical obstruction (such as by a tumor or stricture), a motility disorder, impairment of the upper or lower esophageal sphincter, and others. Dysphagia is common among all age groups, but is especially common among the elderly. Dysphagia occurs after strokes and after many surgeries of the head and neck organs.

Swallowing problems may arise from simple causes such as poor teeth, ill fitting dentures, or a common cold. One of the most common causes of dysphagia is gastroesophageal reflux disease (GERD), which occurs when stomach acid moves up the esophagus to the pharynx, causing discomfort. Other causes may include stroke or progressive neurological disorders, which may impair sensitivity, muscular coordination, or render individuals unable to control or move the tongue. The presence of a tracheostomy tube, vocal cord paralysis, tumors in the mouth, throat, esophagus, or surgery in the head, neck, or esophageal areas may also contribute to swallowing impairments.

Problems Associated with Dysphagia

Impaired swallowing can cause significant health problems. Relatively minor symptoms associated with dysphagia include drooling, the feeling that food is sticking in the throat, discomfort in the throat or chest, and the sensation of a lump in the throat. Other symptoms are more problematic, however, such as inadequate nutrition, dehydration, and weight loss due to significant dysphagia.

Aspiration

Aspiration, which is the passage of food or liquid through the vocal folds (the sensation of food "going down the wrong way"), can be a serious consequence of dysphagia. It may cause chronic coughing, choking, airway obstruction, and if food is aspirated into the lungs, aspiration pneumonia. Aspiration may result from obstruction of the pharynx, weakness or incoordination of the pharyngeal muscles, poor opening of the upper esophageal sphincter, or other impairments. Aspiration is especially problematic the further that material travels into the airways. Physical properties of the aspirated material can also pose particular risks: solid food may cause airway obstruction, and acidic foods or refluxed acidic stomach contents can seriously endanger the lungs, which are sensitive to the effects of acid. Any aspirated material may introduce potentially harmful bacteria into the lungs. In some cases, if a person's sensation or consiousness is impaired, aspiration does not provoke a cough response, which is a particularly dangerous condition.

About one third of individuals who have had a stroke subsequently develop dysphagia, and aspiration pneumonia caused by swallowing problems causes about 40,000 deaths in the US each year. In light of the rapidly growing elderly population, attention to swallowing problems is becoming increasingly important.

Evaluation of Swallowing Problems

To evaluate swallowing problems, your otolaryngologist may recommend tests including:

Transnasal endoscopy (see tne2.htm)
FEESST (see feesst1.htm)
Barium swallow X-ray, or Videofluoroscopy

Speech pathologists, neurologists, radiologists, and other specialists may work together with your otolaryngologist to assess and treat swallowing difficulties.

Treating Swallowing Disorders

Treatments for dysphagia depend on its causes.

Patients with GERD may benefit from modifying their diets and living habits, such as by consuming a bland diet with smaller, frequent meals, eliminating alcohol and caffeine, reducing weight and stress, avoiding food within three hours of bedtime and elevating the head during sleep.
Patients with swallowing disorders caused by stroke, Parkinson's, or other neurological disorders may benefit from direct swallowing therapy, in which they learn to modify their head and neck posture or placement of food in order to facilitate the swallowing process. Patients may also learn to strengthen the swallowing muscles or consciously control them during particular phases of the swallow. Training in feeding techniques, including modifications of the consistency of foods, can be an important part of achieving safe swallowing. See Swallowing Therapy
Medications that slow the production of stomach acid, muscle relaxants, antacids, and other drugs may reduce dysphagia for some patients. For certain problems, such as a narrowing (stricture) in the throat, surgery to dilate or release the area (myotomy) may be required. Tumors or masses may need to be treated with medicines or removed surgically, and patients with vocal cord paralysis may require other specific treatments. please see Vocal cord paralysis or Laryngopharyngeal Reflux Disease
In rare cases, patients can not consume adequate food or liquids despite attempts at treatment, and must receive nutrition through a tube. Patients most likely to require enteral feeding include those with impaired consciousness, massive aspiration, silent aspiration, esophageal obstruction, or recurrent respiratory infections.

Read about Research on Swallowing Problems currently underway at the Department of Otolaryngology.

Credit: Information on this page was adapted from a brochure published by the American Academy of Otolaryngology - Head and Neck Surgery, and from Evaluation and Treatment of Swallowing Impairments, Jeffrey Palmer, the American Family Physician, April 15, 2000.