Achalasia

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Achalasia, also known as esophageal achalasia, achalasia cardiae, cardiospasm, dyssynergia esophagus, and esophageal aperistalsis, is an esophageal motility disorder, a disease in which normal movement of the muscles in the esophagus is disturbed. It is characterized by difficulty swallowing, chest pain and regurgitation. Diagnosis is reached with esophageal manometry. Various treatments are available, but none cure the condition completely. Certain medications may be used, as well as injection of the esophageal muscles with botulinum toxin, but more permanent relief is brought by esophageal dilatation and surgical cleaving of the muscle (e.g. a procedure known as Heller myotomy).^[1][2]

In achalasia, the smooth muscle layer of the esophagus has impaired peristalsis (muscular ability to move food down the esophagus), and the lower esophageal sphincter (LES) fails to relax properly in response to swallowing.^[3] The most common form is primary achalasia, which has no known underlying cause. However, a small proportion occurs as a secondary result of other conditions, such as esophageal cancer or Chagas disease (an infectious disease common in South America).^[1] Achalasia affects one person in 100,000 every year.^[2][1]

[edit] Signs and symptoms

Characteristic symptoms of achalasia are worsening difficulty in swallowing, uniquely involving both fluids and solids simultaneously, and burning chest pain that may resemble heartburn and gastroesophageal reflux. As the esophagus gets more obstructed, undigested food may be regurgitated, especially when reclining or at night where it can cause cough and aspiration of food matter into the lungs.^[1]

[edit] Diagnosis

Given the similarity of many of the symptoms with commoner digestive conditions such as gastroesophageal reflux disease (GERD) and hiatus hernia, diagnosis may be delayed. Only in very severe cases does a very distended part of the esophagus with a fluid level become visible on a standard chest X-ray.^[1]

Specific tests for achalasia are barium swallow and esophageal manometry. A CT scan of the chest and esophagogastroduodenoscopy (endoscopy of the esophagus, stomach and duodenum), with or without endoscopic ultrasound, are typically performed to exclude the possibility of cancer.^[1] Endoscopy is typically normal, although difficulty negotiating the distal esophagus may be observed.

[edit] Barium swallow

A barium swallow investigation requires the patient to swallow a barium solution, with continuous fluoroscopy (X-ray recording) to observe the flow of the fluid through the esophagus. In achalasia, normal peristaltic movement of the esophagus is lost; there is acute tapering at the level of the lower esophageal sphincter and narrowing is observed at the gastro-esophageal junction. The findings are classically described as "parrot's beak" or "rat's tail" appearance. In many cases there is also dilation of the area proximal to the narrowing, which may be very large and containing food debris.^[1]

[edit] Esophageal manometry

Schematic of manometry in achalasia showing aperistaltic contractions, increased intraesophageal pressure and failure of relaxation of the lower esophageal sphincter.

Esophageal motility studies are more sensitive than barium studies. This test involves swallowing a probe that measures muscle contraction in different parts of the esophagus during the act of swallowing. The test is not specific, in the sense that Chagasic achalasia and malignancy can give a similar appearance.^[1]

[edit] Biopsy

Biopsy, the removal of a tissue sample during endoscopy, is not typically necessary in achalasia, but if performed shows hypertrophied of the musculature and absence of the nerve cells that together form the myenteric plexus, the network of nerve fibers that controls esophageal peristalsis. In Chagas disease, a secondary cause of achalasia, the ganglion cells are destroyed by Trypanosoma cruzi, the causative parasite.^[4]

[edit] Treatment

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[edit] Medication

Drugs that reduce LES pressure may be useful, especially as a way to buy time while waiting for surgical treatment. These include calcium channel blockers such as nifedipine, and nitrates such as isosorbide dinitrate and nitroglycerin. Unfortunately, many patients experience unpleasant side effects such as headache and swollen feet, and these drugs often stop helping after several months.

Intra-sphincteric injection of botulinum toxin (or botox), to paralyze the lower esophageal sphincter and prevent spasms. As in the case of botox injected for cosmetic reasons, the effect is only temporary, and symptoms return quickly in most patients. Botox injections cause scarring in the sphincter which may increase the difficulty of later Heller myotomy. This therapy is only recommended for elderly patients who cannot risk surgery.

[edit] Pneumatic dilatation

Balloon (pneumatic) dilation, also called dilatation. The muscle fibers are stretched and slightly torn by forceful inflation of a balloon placed inside the lower esophageal sphincter. Gastroenterologists who specialize in achalasia and have done many of these forceful balloon dilations have better results and fewer perforations than inexperienced ones. There is always a small risk of a perforation which would have to be fixed by surgery right away. Gastroesophageal reflux (GERD) occurs after pneumatic dilation in some patients. Pneumatic dilation causes some scarring which may increase the difficulty of Heller myotomy if this surgery is needed later. Pneumatic dilation is most effective on the long term in patients over the age of 40; the benefits tend to be shorter-lived in younger patients. This treatment may need to be repeated with larger balloons for maximum effectiveness.

[edit] Surgery

Heller myotomy helps 90% of achalasia patients. It can usually be performed by a keyhole approach, or laparoscopically.^[5] The myotomy is a lengthwise cut along the esophagus, starting above the LES and extending down onto the stomach a little way. The esophagus is made of several layers, and the myotomy only cuts through the outside muscle layers which are squeezing it shut, leaving the inner muscosal layer intact. A partial fundoplication or "wrap" is added in order to prevent excessive reflux, which can cause serious damage to the esophagus over time. In a Dor (anterior) fundoplication, part of the stomach is laid over the esophagus and stitched in place so whenever the stomach contracts, it also closes off the esophagus instead of squeezing stomach acids into it. After surgery, patients should keep to a soft diet for several weeks to a month, avoiding foods that can aggravate reflux.

[edit] Follow-up

Follow-up monitoring: Even after successful treatment of achalasia, swallowing may still deteriorate over time. It's important to check every year or two with a timed barium swallow because some may need pneumatic dilations, a repeat myotomy, or even esophagectomy after many years. Some doctors recommend pH testing and endoscopy to check for reflux damage, which may lead to a stricture or cancer of the esophagus if untreated.

[edit] See also

• Heller myotomy

[edit] References

[edit] External links

• and Diseases/Digestive Disorders/Esophagus/ Achalasia at the Open Directory Project
• U.S. Society for Surgery of the Alimentary Tract - guideline about achalasia]
• Patient.co.uk - page on achalasia