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Dysphagia: Definition

  • Dysphagia is difficulty in swallowing. Clinically, it includes the inability to initiate swallowing and/or the sensation that the swallowed solids or liquids stick in the esophagus.
  • Odynophagia refers to pain with swallowing. In some disorders, odynophagia may accompany dysphagia.
  • Globus hystericus describes the sensation of the presence of «a lump in the throat» that is relieved momentarily by swallowing.

Preesophageal or oroesophageal dysphagia

Patients with this disorder have problems with the initial steps of swallowing. They may have difficulty in propelling food to the hypopharynx. If the food passes normally to the hypopharynx, the presence of pain, intra- or extraluminal mass lesion, or a neuromuscular disorder may interfere with the orderly sequence of pharyngeal contraction, closure of the epiglottis, upper esophageal sphincter relaxation, and initiation of peristalsis by contraction of the striated muscle in the upper esophagus.

Signs and symptoms. These patients usually cough and expel the ingested food through their mouth and nose or aspirate when they attempt to swallow. Their symptoms are worse with liquids than with solids. They may have a «wet» voice quality, reduced cough, upper airway congestion, and aspiration pneumonitis.

Causes

  • Central nervous system conditions. Cerebral vascular accidents (bulbar or pseudobulbar palsy), multiple sclerosis, amyotrophic lateral sclerosis, Wilson’s disease, Parkinson’s disease, Friedreich’s ataxia, tabes dorsalis, brainstem tumors, paraneoplastic disorders, reaction to drugs or toxins, other congenital and degenerative disorders of the central nervous system.
  • Peripheral nervous system conditions. Poliomyelitis (bulbar), diphtheria, rabies, botulism, diabetes mellitus, demyelinating diseases, Guillain-Barr syndrome.
  • Disorders of the myoneural junction. Myasthenia gravis, Eaton-Lambert syndrome.
  • Muscular disorders. Dermatomyositis, muscular dystrophies, myotonic disorders, congenital myopathies, metabolic myopathies (thyrotoxicosis, myoedema, steroid myopathy), collagen vascular diseases, amyloidosis.
  • Toxins. Tetanus, botulism, tic paralysis, arsenic, lead, mercury poisoning.
  • Local structural lesions. Conditions involving the mouth, pharynx, and hypopharynx.
  1. Infection or inflammation. Abscess; tuberculosis; syphilis; viral, bacterial, and fungal infections; Lyme disease; diphtheria; rabies.
  2. Space-occupying lesions. Neoplasms, congenital webs, Plummer-Vinson syndrome.
  3. Extrinsic compression. Cervical spine spurs, lymphadenopathy, thyromegaly, Zenker’s diverticulum.
  4. Trauma. Surgical repair, foreign body ingestion, caustic injury.

Motility disorders of the upper esophageal sphincter. Hypertensive upper esophageal sphincter, hypotensive upper esophageal sphincter with esophagopharyngeal regurgitation, abnormal upper esophageal sphincter relaxation (incomplete relaxation: cricopharyngeal achalasia, premature closure, delayed relaxation).

Esophageal dysphagia describes difficulty with transport of food down the esophagus once the bolus has been successfully transferred into the proximal esophageal lumen. Any disorder, structural or neuromuscular, involving the body of the esophagus, the lower esophageal sphincter, or the gastroesophageal junction may result in dysphagia or the sensation of food being «stuck» behind the sternum. If the patient can localize the symptom to some point along the sternum, a good correlation with the anatomic site is possible. However, if the symptoms are felt at the sternal notch, the anatomic site of the lesion cannot be predicted.

Structural disorders are usually caused by a discrete lesion such as a neoplasm, stricture, or extrinsic compression that interferes with the transport of the swallowed bolus. Initially, dysphagia is noted with solid foods. However, as the lumen narrows with enlarging lesions, passage of liquids also becomes impaired.

Tumors

Squamous carcinoma accounts for approximately one third of all esophageal cancers. Excessive alcohol intake and cigarette smoking seem to increase the risk. Other predisposing factors include head and neck cancer, Plummer-Vinson syndrome (anemia and esophageal web), tylosis, achalasia, and lye stricture.

Adenocarcinoma of the esophagus constitutes about two thirds of esophageal cancers. It is thought to arise from extension of gastric cardia carcinoma, from the esophageal glands or, more commonly, from the columnar metaplasia of the esophagus (Barrett’s epithelium).

Kaposi’s sarcoma, lymphoma, melanoma, and metastatic tumors from the lungs, pancreas, breasts, and other structures may also involve the esophagus.

Benign tumors of the esophagus are rare and account for less than 10% of esophageal tumors. These tumors most commonly arise from neuromesenchymal elements. Leiomyomas that arise from esophageal smooth muscle are the most common. These intramural lesions are covered by normal squamous epithelium of the esophagus. They protrude into the lumen, eventually causing narrowing of the passage. Other lesions such as fibroadenomas, though rare, may become very long and large and may cause obstruction.

Strictures

  • Peptic strictures. Most esophageal strictures are found in the distal or mid esophagus and are the result of chronic inflammation caused by gastroesophageal reflux. Peptic strictures are usually benign, but those associated with Barrett’s epithelium may be malignant.
  • Burns caused by ingestion of corrosive substances (e.g., strong alkali and acids) may result in esophageal strictures in single or multiple locations of the esophagus.
  • Some drugs in tablet form may lodge in a segment of the esophagus and cause local inflammation, ulceration, and stricture.
  • Foreign bodies, (e.g., coins or button batteries) may be swallowed and cause obstruction or injury of the esophagus.

Rings and webs are usually thin, circumferential mucosal shelves that protrude into the esophageal lumen and cause intermittent dysphagia, especially to solids. Webs occur in the upper esophagus and may be associated with iron-deficiency anemia (Plummer-Vinson syndrome).

Rings (Schatzki) are most often found at the gastroesophageal junction. Schatzki’s rings seem to be related to chronic gastroesophageal reflux. Most of these contain only mucosal elements; however, thicker ones may also contain a thickened muscle layer.

Extrinsic compression. The esophageal lumen may be narrowed from compression by an external lesion. These lesions include the following:

Mediastinal tumors, primary or metastatic.

Vascular lesions, such as aberrant right subclavian artery (dysphagia lusoria), a dilated aneurysmic aorta, or an enlarged cardiac chamber.

Cervical osteoarthritis and bone spurs.

Esophageal diverticula may cause dysphagia when they become large and distended with food and secretions. They tend to occur in three main parts of the esophagus: just above the upper esophageal sphincter (Zenker’s), at the middle (traction), and near the diaphragm (epiphrenic). Zenker’s and epiphrenic diverticula are thought to result from motor abnormalities of the esophagus. Even though mid-esophageal diverticula have been attributed to traction on the walls of the esophagus by external inflammatory and fibrotic processes (e.g., tuberculosis or sarcoidosis) they also may result from abnormal esophageal motility.

Gastroesophageal reflux. The reflux of the gastroduodenal contents into the esophagus may cause dysphagia in some patients, especially if severe inflammation, ulceration, or stricture develops. With resolution of the inflammation and edema, dysphagia may abate. In some patients, gastroesophageal reflux may result in esophageal motility disorders, which may contribute to dysphagia and chest pain.

Neuromuscular or motility disorders result in dysphagia to both liquids and solids due to aberrant peristalsis. These disorders are present in about half the patients who have dysphagia without an evident structural abnormality. In these disorders, peristalsis is either absent, weak, too strong and sustained, or uncoordinated. The lower esophageal sphincter function may also be abnormal. The resting lower esophageal sphincter pressure may be too high or low, and the sphincter may not relax completely on swallowing.

Primary motor disorders

Achalasia is a disorder of esophageal smooth-muscle function with three diagnostic prerequisites. First, there is a complete absence of primary and secondary peristalsis in the smooth muscle of the esophagus. Skeletal muscle function is generally normal. Second, the lower esophageal sphincter does not relax completely with swallows. Third, the resting lower esophageal sphincter pressure is usually high. The lack of peristalsis and the sustained high-pressure zone at the gastroesophageal junction results in retention of ingested material and oral secretions in the esophagus with gradual loss of tone and progressive dilatation of the body of the esophagus.

Cause. Achalasia is most likely the result of neuronal abnormalities rather than a primary myopathy. Lesions have been found in the dorsal vagal nucleus in the brainstem, in the vagal trunks, and in the myenteric ganglia in the esophagus. Secondary achalasia may resemble primary achalasia. It may result from tumor invasion of the lower esophageal sphincter region, constriction from malignant nodes, or paraneoplastic syndromes.

Signs and symptoms. Patients with achalasia consistently have dysphagia to both solids and liquids. Occasionally, early in the disease and in patients with «vigorous achalasia,» chest pain may occur. Regurgitation of esophageal contents often with tracheal aspiration is a common complication of the disease.

Treatment of achalasia is designed to decrease the pressure in the lower esophageal sphincter. This allows the aperistaltic esophagus to empty in the upright position. lower esophageal sphincter myotomy may be accomplished surgically (open or laparoscope) or by forceful dilatation with an inflatable, pneumatic peroral balloon dilator or by intramucosal injection of Botulinum toxin endoscopically. Medical management of achalasia is usually unsuccessful. In some patients, calcium channel blockers may lower the lower esophageal sphincter pressure and produce transient symptomatic improvement.

Diffuse esophageal spasm. This entity accounts for about 10% to 15% of patients with esophageal motility disorders. Patients with this disorder have high-amplitude, simultaneous contractions in the smooth-muscle portion of the esophageal body. Skeletal muscle function is normal. The «spastic» waves are usually initiated by swallows but may occur randomly interspersed with normal-appearing peristalsis. The lower esophageal sphincter may have normal or high pressure and may not completely relax with swallowing.

Signs and symptoms. In these patients, dysphagia is intermittent. It occurs with both liquids and solids. Sometimes it is exacerbated with hot or cold foods and may cause chest pain. In fact, the chest pain of Diffuse esophageal spasm is often confused with angina pectoris. Thus, it is important in these patients to exclude possible cardiac disease.

Treatment of Diffuse esophageal spasm is generally directed toward decreasing the frequency and intensity of simultaneous contractions. Smooth muscle relaxants, including nitrates (e.g., nitroglycerin, 0.4 mg sublingually a.c. and prn); isosorbide dinitrate, 30 mg per os (p.o.) 30 minutes a.c.; hydralazine, 25 to 50 mg p.o. three times daily; calcium channel blockers (e.g., nifedipine, 10-20 mg, four times daily); psychotropic drugs (e.g., diazepam 1-5 mg p.o., four times daily; trazodone 50-100 mg p.o., twice daily; doxepin, 50 mg p.o., h.s.); and anticholinergics (e.g., dicyclomine 10-20 mg p.o., four times daily) have been tried with variable results.

Because abnormal motility is not always documented in patients with dysphagia secondary to dysmotility, provocation of symptoms and manometric findings with drugs may be attempted. Edrophonium is the best tolerated and most effective of currently available drugs.

Bougienage and pneumatic dilatation sometimes yield transient symptom relief. In difficult cases, surgical myotomy may be tried. The outcome is often variable, and successful relief of symptoms is rare.

«Vigorous achalasia» An overlap between Diffuse esophageal spasm and achalasia called vigorous achalasia has been observed in some patients. In this condition, in addition to simultaneous, high-amplitude contractions in the distal esophagus as in Diffuse esophageal spasm, the lower esophageal sphincter function is similar to that in achalasia. The symptoms are usually chest pain and dysphagia. This overlap, as well as a transition from Diffuse esophageal spasm to achalasia in some patients, suggests that these two disorders may be different manifestations of the spectrum of esophageal smooth muscle dysfunction.

Nutcracker esophagus or «super squeezer» is a motility disorder found in approximately one half of the patients with chest pain of esophageal origin and one tenth of the patients with dysphagia. These patients have normal lower esophageal sphincter function and peristalsis; however, the contractile amplitude is usually two to three times the normal value. Most of these patients also have an abnormal prolongation of the peristaltic wave. A subgroup of patients with contraction waves of normal amplitude but prolonged duration also has been described.

The symptoms of patients with nutcracker esophagus are similar to those associated with Diffuse esophageal spasm. Patients may have prolonged chest pain, which may be nocturnal, and intermittent dysphagia. The nutcracker esophagus may evolve into Diffuse esophageal spasm, suggesting that these disorders are related. Treatment of nutcracker esophagus is similar to treatment of Diffuse esophageal spasm.

Nonspecific esophageal motor disorders. Most patients with symptoms of esophageal dysmotility cannot be classified neatly into specific groups. The incidence of these disorders of the peristaltic wave or lower esophageal sphincter function is at least five times that of achalasia and Diffuse esophageal spasm combined. The patients may have an isolated abnormality of the lower esophageal sphincter (increased pressure, incomplete relaxation, hypertensive lower esophageal sphincter) with or without abnormal esophageal contractions (increased amplitude or duration, simultaneous contractions, nonpropagated waves).

Treatment. There is no reliable therapy for patients with nonspecific esophageal motor disorders. Smooth-muscle relaxants have been tried as in Diffuse esophageal spasm, again with variable results. Bougienage may give transient relief in some patients.

Patients with diabetes mellitus may have abnormal esophageal motility such as poor propagation of the peristaltic wave and diffuse spasm, most likely due to visceral neuropathy.

Secondary motor disorders. Esophageal smooth-muscle dysfunction may be associated with a number of systemic disorders.

Scleroderma

Approximately 80% of the patients with scleroderma, particularly those who exhibit Raynaud’s phenomenon, have decreased amplitude of peristalsis in the smooth-muscle portion of the esophagus with decreased resting lower esophageal sphincter pressure. Initially, the disorder seems to be neural; however, with progression of the disease, collagen deposition and fibrosis of the smooth muscle are observed. These patients are a setup for severe reflux esophagitis, which is frequently complicated by stricture formation and Barrett’s esophagus.

Other diseases. The abnormal esophageal motility associated with scleroderma has been reported in some patients with other collagen vascular diseases and those with Raynaud’s phenomenon. Patients with polymyositis and lupus also may exhibit esophageal smooth muscle dysfunction.

Chagas’ disease

An achalasialike disease has been seen as a secondary disorder with Chagas’ disease (infection with Trypanosoma cruzi).

Tumors of the mediastinum, lower esophagus, gastroesophageal junction, and gastric cardia, as well as lymphoma and pancreatic and bronchogenic carcinoma may also present as achalasia. Tumors may invade the myenteric plexus or produce an obstruction at the gastroesophageal junction; thus, aperistalsis may be secondary to neural invasion or a response to lower esophageal sphincter obstruction.

Chronic idiopathic intestinal pseudoobstruction usually involves the esophagus as well as all other parts of the gastrointestinal tract. The esophageal abnormality includes aperistalsis and incomplete relaxation of lower esophageal sphincter, producing a functional obstruction. Patients with this disease usually have either congenital or acquired neuromuscular degeneration of the entire gut, affecting the neural plexuses and the myenteric ganglia.

Reflux esophagitis and esophageal dysmotility. Patients with gastroesophageal reflux and reflux esophagitis have been shown to have a number of abnormalities of smooth-muscle function. These include a low resting lower esophageal sphincter pressure; abnormal, prolonged periods of relaxation of the lower esophageal sphincter; and decreased esophageal clearance due to disorder of primary and secondary peristaltic waves. It is difficult to determine whether these defects are a primary cause of reflux or a result of the associated esophagitis.

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