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Dysphagia, a common symptom in those with esophageal disorders, may arise from a multitude of underlying causes. Dysphagia or difficulty swallowing refers to a sensation of impairment of the normal progression of the bolus from the mouth into the stomach. Dysphagia should be distinguished from odynophagia or pain upon swallowing. Recognizing dysphagia and gauging its clinical significance appears simple. There are, however, several important points that may be brought up by the following questions:
Proper clinical evaluation of dysphagia requires a detailed history.1 Multiple diagnostic techniques are available and their use depends upon the presenting clinical features. The initial test however is often a barium swallow or an endoscopic examination. The choice between these two techniques, as the most useful and least costly for the evaluation of dysphagia, is the subject of debate. In a patient who presents with intermittent solid dysphagia, suggesting a benign obstructing lesion such as peptic stricture or ring, starting with endoscopy is reasonable as it allows making the diagnosis and simultaneously treating the lesion by dilation. In cases of dysphagia to both solids and liquids and suspicion of a motor disorder, a barium swallow provides more useful information by evaluating esophageal peristalsis. The guidelines of the American Gastroenterological Association (AGA) support the choice of barium swallow in these cases, a recommendation that most clinicians would agree with.2 Various known causes of esophageal disorders may be classified into four different groups:
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Definition and ClassificationPRIMARY MOTOR DISORDERS PrevalencePathophysiology Signs
and
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The term esophageal motor disorder or esophageal motility disorder is used to describe abnormal esophageal motility patterns found in the process of testing patients with chest pain and/or dysphagia. This definition implies the absence of an obstructing lesion of the esophagus. Motility disorders may be caused by an abnormality of the proximal striated muscle portion of the esophagus or by the distal smooth muscle portion. Proximal motor disorders are neurogenic or myogenic in origin such as disturbances seen after cerebral vascular accidents or in the course of a progressive degenerative muscular disorder. The discussion will be limited here to disorders of the smooth portion of the esophagus which is responsible for the involuntary phase of swallowing. These diseases may be primary in which the abnormality is limited to the esophagus or secondary in which the esophageal lesion is part of a system disorder. Primary Disorders
Secondary Disorders
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The exact prevalence of esophageal motor disorders is unknown. In one study, 28% of patients presenting with chest pain were found to have abnormal esophageal motility tests.1 The annual incidence of achalasia is estimated at 0.4 -1.2 in the Western world. Diffuse esophageal spasm is found in 2% of patients referred to a motility laboratory. These figures do not reflect the prevalence of any of these disorders in the general population and may indicate that such disorders are generally rare. They are, however, frequent enough to be encountered by every gastroenterologist in his or her practice as well as by general internists who are faced with these problems from time to time.2 |
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Esophageal motor disorders involve a disturbance of esophageal peristalsis. In the normal state, once the voluntary oropharyngeal phase of swallowing takes place, a well-coordinated peristaltic sequence travels distally toward the lower esophageal sphincter (LES). The orderly succession of contractions from one segment to the next is possible because of a progressively longer latency period to stimulus from one esophageal segment to the next. The LES relaxes almost immediately after relaxation of the upper sphincter, thus providing an open passage in anticipation of the incoming bolus. Both esophageal peristalsis and relaxation of the lower sphincter are mediated by the vagus nerve but the function is controlled by the intramural plexus of Auerbach. In achalasia, there is a total loss of peristalsis and the LES relaxes poorly. The disease results from a neurologic deficit in the myenteric plexus. There is a marked decrease in myenteric ganglion cells with marked inflammatory changes.3 The lower esophageal sphincter dysfunction is due to the destruction of inhibitory nerve fibers which normally reduce sphincter tone and control sphincter relaxation. Their absence leads to poor reduction of the sphincter's resting tone. The cause of the disorder is unknown.4 In diffuse esophageal spasm, there is intermittent loss of peristalsis resulting in simultaneous, often repetitive contractions but peristalsis is recovered intermittently. LES is usually normal.5 Severe reflux esophagitis is often accompanied by low LES pressure and decreased distal contraction amplitude. In the nutcracker esophagus, peristalsis is normal but the contraction amplitude is much higher than usual. Duration is also prolonged.6 |
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Dysphagia Chest
Pain Recurrent chest pain, in the absence of dysphagia, is a frequent reason for gastroenterologic consultation from internists and cardiologists. Most patients are men, complaining of retrosternal pain, who have had several visits to the emergency department and in whom cardiac disease has been ruled out. The concept of non-cardiac chest pain due to esophageal disease has been exaggerated. The term "esophageal spasm" is often used without any objective evidence and the chest pain has sometimes been attributed to non-specific motor changes noted on manometry or to the nutcracker esophagus. The most frequent cause of chest pain originating from the esophagus is related to acid reflux. Motor disorders account for less than 30% of cases of chest pain studied in a manometry laboratory. Heartburn Regurgitation Weight
Loss Cancer
and Achalasia Pseudoachalasia is a syndrome simulating achalasia and caused generally by malignant tumors near or at the esophagogastric junction. The clinical, radiologic and manometric findings are often indistinguishable from primary achalasia. Although most cases are seen in elderly patients with recent onset dysphagia, the abnormality has been observed in young people.7 For this reason, all patients with achalasia should undergo endoscopy and any suspicious lesion should be biopsied before definitive treatment is entertained. |
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History Physical
Examination Barium
Swallow In diffuse esophageal spasm, tertiary contractions produce multiple indentations and pseudodiverticular deformities (Figure 1). The presence of these changes however does not allow the diagnosis of symptomatic spasm without knowledge of associated symptoms. In achalasia, x-ray reveals a typical smooth tapering of the esophagogastric junction which has been compared to a bird's beak (Figure 2). Esophageal peristalsis is abnormal and the passage of both solid and liquid media is delayed. In later stages, the esophagus is dilated and food residue may be present. Large diverticula develop over time and the esophagus becomes tortuous assuming a sigmoid shape (Figure 3). Endoscopy Esophageal
Manometry Esophageal manometry is indicated:
Esophageal manometry nonindicated:
In normal individuals, esophageal motility testing reveals normal progression of the peristaltic wave with timely relaxation of the lower esophageal sphincter (Figure 4). In achalasia, LES relaxation is partial and ill-timed and peristalsis is totally absent (Figure 5). In diffuse esophageal spasm, tertiary contractions are seen with alternating normal contractions (Figure 6). The nutcracker esophagus reveals high amplitude long-duration contractions (Figure 7). Patients with ineffective motility most often due to reflux disease show intermittent lack of progression in the distal esophagus and low amplitude contractions (Figure 8). Other motor abnormalities do not correspond to any clinical syndrome and they are referred to as non-specific motor changes, a convenient but not clinically relevant category.9 |
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treatment of esophageal motor disorders depends on establishing a specific
diagnosis. In some patients, numerous investigations do not provide enough
information for such a purpose. In those cases, reassurance and advice to
eat with caution are generally sufficient. Empiric dilation with bougie
dilators is sometimes helpful.
For diffuse esophageal spasm, calcium channel blockers, anticholinergics and mild sedatives have had various degrees of success. As already pointed out, diffuse spasm is a rather rare disorder and symptoms are rarely disabling. A long surgical myotomy is indicated in extremely rare cases when dysphagia is disabling. The treatment of achalasia includes several options although no therapy can restore muscular activity to the denervated achalasic esophagus. Treatment is therefore limited to reducing the gradient of pressure represented by the lower sphincter. This goal may be accomplished by one of four methods.
Pharmacologic Agents: Long acting nitrates and calcium channel blockers reduce LES pressure and improve esophageal emptying. However, effective doses produce side effects such as headaches and hypotension and the drugs tend to become less effective with time. It is recommended that calcium channel blockers be used sublingually to ensure absorption as delayed passage through the esophagus would retard their effect. Pneumatic Dilation: Dilation with bougies and small balloons produce brief results. In elderly and frail patients, periodic bougie dilations offer temporary relief and should not be entirely disregarded. Pneumatic dilation is a forceful disruption of the lower esophageal sphincter with the use of a large balloon capable of achieving high pressures. Most specialists in the United States use the Rigiflex balloon (Figure 9) which can be passed around a guidewire during endoscopy, is visible under fluoroscopy and easy to maneuver. The procedure is carried out with sedation and under fluoroscopy so the balloon is positioned at the level of the diaphragm. The balloon is inflated until the waist at the gastroesophageal junction disappears. The duration of the distention varies from report to report but an inflation of 30 seconds is reasonable. The patient experiences some chest pain and, upon withdrawal of the device, blood streaks are often seen on the balloon. There is a 2 to 6% risk of perforation. This is why a radiologic study is obtained immediately after the procedure to rule out perforation which, if present, would require thoracotomy and surgical repair. The procedure is successful in 65 to 90% of patients. The technique of graded dilation has been advocated starting with a smaller balloon size of 3 cm and repeating the procedure with larger balloons at later dates. This method is accompanied by a lower initial success rate but seems to reduce the number of complications.10 Surgical Myotomy: Surgical myotomy or Heller's myotomy, named for the German surgeon who performed it first in 1914, aims at releasing LES pressure by performing a longitudinal muscular incision which extends above the esophagogastric junction but not too far distally to avoid acid reflux. There are very few studies comparing pneumatic dilation and Heller's myotomy for the treatment of achalasia.11,12 Myotomy appears more successful than pneumatic dilation with success rates of 85% to 95%. The advent of laparoscopic myotomy, resulting in less morbidity and a shorter hospital stay, has made the procedure much more attractive as initial treatment option.13 The choice between pneumatic dilation and surgical myotomy should be made by the patient with the assistance of his or her physician. The patient should be treated in an institution that offers expertise in both procedures. Failure of pneumatic dilation does not preclude surgical treatment. Some patients have undergone pneumatic dilation after surgery as well. The Society for Surgery of the Alimentary Tract (SSAT) has published a guideline on the surgical treatment of achalasia.14 The recommendations are vague and the required qualifications to perform such surgery are based on board certification and eligibility and "training and experience." Botulinum Toxin: Botulinum toxin acts by inhibiting the release of acetycholine from nerve terminals at the level of the LES.15 A powder containing 100 units of the toxin is diluted with normal saline and injected during endoscopy in a quadrant fashion at the level of the gastroesophageal junction. Swallowing improves in about 85% of patients but the effect of the drug wanes with time so that at 6 months, only 50% report improvement. Repeated injections are necessary. The best indication for Botulinum toxin is in elderly patients whose general condition is deemed too risky for either pneumatic dilation or surgery or for patients who refuse both treatment modalities. The approach to treatment of patients with achalasia is summarized in a practice guideline document from the American College of Gastroenterology which discusses treatment options in great detail and provides a good algorithm for management of achalasia (Figure 10).10 |
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| Treatment results and long term follow-up are available only for patients with achalasia. Treatment of achalasia is a lifetime process. Various analyses have been made to find predictors of outcome. It appears that younger patients defined as being 40 years of age or less, require more aggressive treatment but the frequency of intervention varies greatly from patient to patient. | ||||
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SECONDARY
MOTOR DISORDERS
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In these cases, the esophageal abnormality is secondary to a generalized disorder and other organs besides the esophagus are affected. Although esophageal motor changes have been noted in various disorders, the following are the most common:
Diabetes and other systemic diseases produce some changes in esophageal peristalsis but patients are usually asymptomatic. Chronic idiopathic pseudoobstruction is a diffuse motor disorder of the gastrointestinal tract manifested by recurrent attacks of intestinal obstruction. The study of esophageal function reveals repetitive contractions, segmental loss of peristalsis and other non-specific findings. Patients, however, infrequently report esophageal symptoms. An abnormal esophageal manometry test may lead to the diagnosis if indeed the esophagus is affected. A significant motor abnormality is associated most often with progressive systemic cirrhosis or scleroderma. Scleroderma is a multisystem sclerosing disease affecting most notably skin, lungs, and the esophagus. Seventy-five percent of patients with scleroderma have esophageal involvement but only a fraction have symptoms referring to the esophagus. |
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The esophagus reveals atrophy and sclerosis of the distal smooth muscle with fragmentation of connective tissue. The lower esophageal sphincter is also affected. As a result, normal peristalsis is lost and the lower esophageal sphincter pressure is decreased. |
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Patients with scleroderma manifest with signs of gastroesophageal reflux disease. Dysphagia is not common until a stricture develops. This is probably because the poor peristaltic activity is offset by the reduced lower esophageal sphincter pressure enabling food to pass through the esophagogastric junction. Raynard's phenomenon correlates best with the presence of abnormal esophageal motility whether skin changes are present or not. |
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DIAGNOSIS
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| The barium swallow shows a normal swallowing mechanism in the upper third but delay in progression of the bolus in the distal part of the esophagus. The lower esophageal sphincter is patent and free reflux is often reported at fluoroscopy strictures may be encountered (Figure 11). Endoscopy confirms the presence of esophagitis and allows gauging the severity of the inflammation as well as ruling out ulcers and strictures. Esophageal manometry reveals low esophageal sphincter pressure and weak simultaneous contractions in the distal two-thirds of the esophagus (Figure 12). The proximal esophagus may reveal normal contractions although occasionally the entire esophagus is involved. | ||||
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TREATMENT
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The treatment in scleroderma is directed to reflux, involving potent acid suppressing agents and dilation of strictures when necessary. Strictures tend to be recalcitrant to treatment and frequent dilations are necessary. |
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