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Esophageal Motor Disorders    Achalasia - Esophageal Spasm

REF: Cleveland Clinic: Current Clinical Medicine, 2nd ed. 2010

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. 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. 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. 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.

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. 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. 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.

Signs and Symptoms of Esophageal Spasm 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.

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Diagnosis History The history is of extreme importance in the diagnosis of esophageal motor disorders. As mentioned earlier, patients with motor disorders are often treated for acid reflux or worked up for cardiac disease. In particular, the diagnosis of achalasia is entertained with a high degree of suspicion if a detailed history is obtained. Physical Examination The physical examination is usually unremarkable, except in patients who suffer from malnutrition. Diagnostic Tests 1.  Barium Swallow When a barium swallow is performed in a patient suspected of esophageal motility disorder, it should be accompanied by a videographic study. A solid bolus such as a barium tablet should always be used. The examiner is able to observe peristaltic abnormalities. In diffuse esophageal spasm, tertiary contractions produce multiple indentations and pseudodiverticular deformities. The presence of these changes, however, does not allow the diagnosis of symptomatic spasm without knowledge of associated symptoms. In achalasia, the x-ray reveals a typical smooth tapering of the esophagogastric junction, which has been compared with a bird's beak. 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. 2.  Endoscopy The upper endoscopic examination is usually normal, unless the motor abnormality is associated with severe reflux disease. The importance of endoscopy in detecting tumors that cause pseudoachalasia has already been mentioned. 3.  Esophageal Manometry Esophageal manometry is the most specific test for determining the exact nature of the motor abnormality. The test is indicated in cases of dysphagia in which structural lesions have already been ruled out by x-ray or endoscopy. The yield is very low in patients with noncardiac chest pain without dysphagia. In those cases, prolonged pH monitoring is more useful, because acid reflux causing chest pain is more frequent than disordered peristalsis. AGA guidelines have appropriately outlined the indications for esophageal manometry.

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Treatment The 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. Empirical dilation with bougie dilators is sometimes helpful. For diffuse esophageal spasm, calcium channel blockers, anticholinergics, and mild sedatives have had varying degrees of success. As already noted, diffuse spasm is a rather rare disorder and symptoms are rarely disabling. A long surgical myotomy is indicated in extremely rare cases in which dysphagia is disabling. The treatment of achalasia includes several options, although no therapeutic modality 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, forceful (pneumatic) dilation, surgical myotomy, or endoscopic injection of botulinum toxin. Pharmacologic Agents Long-acting nitrates and calcium channel blockers reduce LES pressure and improve esophageal emptying. However, effective doses can produce adverse 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, because delayed passage through the esophagus would retard their effect. Pneumatic Dilation Dilation with bougies and small balloons produce brief results. In older and frail patients, periodic bougie dilations offer temporary relief and should not be entirely disregarded. Botulinum Toxin Botulinum toxin acts by inhibiting the release of acetylcholine from nerve terminals at the level of the LES.[16] A powder containing 100 U 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 for older patients whose general condition is deemed too risky for pneumatic dilation or surgery, or for patients who refuse both treatment modalities. Surgical Myotomy Surgical myotomy, or Heller's myotomy, named for the German surgeon who first performed it in 1914, aims at releasing LES pressure by performing a longitudinal muscular incision that extends above the esophagogastric junction.

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Outcomes Treatment results and long-term follow-up studies are available only for patients with achalasia. Treatment of achalasia is a lifetime process. Various analyses have been carried out to find predictors of outcome. It appears that younger patients—those 40 years of age or younger—require more aggressive treatment. Young men have generally been shown to have a less favorable response to pneumatic dilation than older men and women.

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        2010