Motor Disorders of the Esophagus

Motor Disorders of the Esophagus



Edgar Achkar


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 on swallowing. Recognizing dysphagia and gauging its clinical significance appears not to difficult. There are, however, several important points that may be brought up by the following questions:


• Is the patient actually complaining of dysphagia? In most cases, patients can clearly express symptoms of difficulty in swallowing. Alternative terms, such as food sticking or food moving down slowly into the chest, may assist in identifying those with dysphagia.

• Is the dysphagia for solids, liquids, or both? Mucosal lesions, benign or malignant, that produce a narrowing of the esophageal lumen will not usually interfere with the passage of liquid substances, and dysphagia is limited to solid foods. On the other hand, disorders impairing esophageal peristalsis will cause difficulty with both solids and liquids.

• Is the dysphagia intermittent or progressive? Structural lesions of the lower esophagus, such as rings and strictures, produce intermittent obstruction related to the size of the bolus, often with prolonged periods free of symptoms. In motor disorders, on the other hand, dysphagia is insidious and becomes progressively worse.

A proper clinical evaluation of dysphagia requires a detailed history.1 A number of diagnostic techniques are available and their use depends on the manifesting clinical features. The initial test 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, has been the subject of debate. In a patient who presents with intermittent solid dysphagia, suggesting a benign obstructing lesion such as a peptic stricture or ring, starting with endoscopy is reasonable because it allows making the diagnosis and treating the lesion by dilation simultaneously. In cases of dysphagia with 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)2 have supported the choice of barium swallow in these cases, a recommendation with which most clinicians would agree.


Various known causes of esophageal disorders may be classified into four different groups:


1 Disorders caused by mucosal injury

2 Neoplastic disorders

3 Anomalies of esophageal lumen

4 Motor disorders


DEFINITION AND CLASSIFICATION


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, dysphagia, or both or in patients being considered for surgical treatment of acid reflux disease. 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 of 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 here will be limited 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 systemic disorder. Primary disorders include achalasia, diffuse esophageal spasm, nutcracker esophagus, motility changes caused by gastroesophageal reflux disorder (GERD), and nonspecific abnormalities. Secondary disorders include scleroderma, chronic idiopathic intestinal pseudo-obstruction, diabetes, and other systemic disorders.



PRIMARY MOTOR DISORDERS



Prevalence


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 test results.1 The annual incidence of achalasia is estimated at 0.4 to 1.2 per 100,000 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 occasionally faced with these problems.3



Pathophysiology


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.4 The disease results from a neurologic deficit in the myenteric plexus. There is a marked decrease in myenteric ganglion cells with marked inflammatory changes.5 The lower esophageal sphincter dysfunction is caused by 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.6


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.7 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.8



Signs and Symptoms



Dysphagia


The cardinal symptom in esophageal motor disorders is dysphagia. This is most typical of patients with achalasia although, in the early phases, dysphagia may be limited to solids. As the disease progresses, patients avoid meat but continue to report difficulty with leafy vegetables, bread, pastas, and frequently liquids. Symptoms are aggravated by hasty eating or emotional upset. Patients learn to eat slowly and use certain maneuvers, such as arching the back or raising the arms, to ease progression of the food bolus. “Washing foods down” with liquids is often ineffective, and relief is only obtained by belching and regurgitation of undigested food. The process may become so embarrassing that patients avoid eating in public. Patients with motility disorders other than achalasia seem to have less-frequent and less-severe dysphagia.



Chest Pain


When chest pain occurs in a patient with dysphagia and in whom a structural lesion and all causes of esophagitis have been ruled out by x-ray and endoscopy, a motility disorder is suspected. In diffuse esophageal spasm, chest pain varies in frequency, intensity, and location. Patients report some relief with nitroglycerin or calcium channel blockers. In achalasia, chest pain is reported by approximately 50% of patients and is prominent in the early stages of the disease. The pain is retrosternal, may be aggravated by meals, and is occasionally nocturnal. It may be partially relieved by antacids or calcium channel blockers. The pain is significantly less frequent and less severe in older adults than in younger patients.


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 noncardiac chest pain caused by esophageal disease has been exaggerated. The term esophageal spasm is often used without any objective evidence; the chest pain has sometimes been attributed to nonspecific 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


Heartburn is not characteristic of disturbed esophageal motility. In achalasia, however, patients may complain of retrosternal burning, a symptom caused by food stasis and not by acid reflux. Unfortunately, I have seen many patients treated for a long time for gastroesophageal reflux disease based on the presence of heartburn because no inquiry is made about dysphagia.



Regurgitation


Regurgitation is often seen in patients with achalasia who are unable to facilitate the passage of solid foods by drinking fluids. The food particles are undigested and may be brought up several hours after ingestion.



Weight Loss


Weight loss is rare in esophageal motility disorders. In spite of the struggle associated with eating, weight loss is surprisingly mild or nonexistent in most patients with achalasia. Review of more than 400 of our patients with achalasia seen at the Cleveland Clinic revealed weight loss at the time of presentation in 57% of patients, but it was generally mild. In a few patients, however, weight loss is so prominent that achalasia may be mistaken for anorexia nervosa, particularly in adolescent girls. The issue is complicated by the fact that esophageal motor disorders are common in patients fulfilling the diagnostic criteria for primary anorexia nervosa and because psychiatric symptoms are common in patients with esophageal motor abnormalities. Therefore, in an adolescent girl with weight loss and regurgitation, esophageal motor abnormalities such as achalasia must be ruled out.



Cancer and Achalasia


Achalasia may predispose to squamous cell carcinoma. Indeed, cases of squamous cell carcinoma of the esophagus have been reported in patients with achalasia, perhaps as a result of prolonged stasis, but the review of large series does not indicate a significantly increased risk. Therefore, surveillance endoscopy for cancer screening in achalasia is not recommended (American Society for Gastrointestinal Endoscopy [ASGE] guideline).


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 those of primary achalasia. Although most cases are seen in older patients with recent-onset dysphagia, the abnormality has been observed in young people.9 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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Jul 18, 2017 | Posted by in GENERAL SURGERY | Comments Off on Motor Disorders of the Esophagus

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