Achalasia is a rare disease of the muscle of the esophagus (swallowing tube) which is usually diagnosed in young adults. The term achalasia means "failure to relax" and refers to one of the abnormalities of the esophagus seen in the disease, specifically, the inability of the muscle at the lower end of the esophagus (the lower esophageal sphincter) to open and let food pass into the stomach. In addition, the muscle of the lower half of the esophagus does not contract normally to propel food down the esophagus and into the stomach. Both of these abnormalities result in food sticking in the esophagus after it is swallowed.
The cause of achalasia is unknown. Theories on cause include infection, heredity or an abnormality of the immune system which causes the body, itself, to damage the esophagus. None of these potential causes has been proven.
When the muscle of the lower esophagus is examined under the microscope, inflammation is seen, and a less than normal amount of nerves that control the muscle are present. It is believed that the nerves which are lacking are those that cause the lower esophageal sphincter to relax. As a result, the sphincter does not relax but remains contracted or narrowed.
The symptoms of achalasia are difficulty swallowing and, sometimes, chest pain. Regurgitation of food that is trapped in the esophagus can occur, and this can lead to coughing or breathing problems when the regurgitated food enters the throat or lungs.
The diagnosis of achalasia usually is made by an x-ray study called a video-esophagram in which video x-rays of the esophagus are taken after barium is swallowed. The barium fills the esophagus, and the emptying of the barium into the stomach can be observed. In achalasia, the video-esophagram shows that the esophagus is dilated (enlarged or widened), with a characteristic tapered narrowing of the lower end sometimes likened to a "bird's beak." In addition, the barium stays in the esophagus longer than normal before passing into the stomach.
Another test, esophageal manometry, can demonstrate specifically the abnormalities of muscle function that are characteristic of achalasia, that is, the failure of the muscle to contract with swallowing and the failure of the lower sphincter to relax. For manometry, a thin tube that measures the pressure generated by the contracting esophageal muscle is passed through the nose and into the esophagus. In a patient with achalasia, no wave of pressure due to muscular contraction is seen in the lower half of the esophagus after a swallow, and the pressure within the contracted sphincter does not relax with the swallow. An advantage of manometry is that it can diagnose achalasia early in its course at a time in which the video-esophagram may be normal.
Endoscopy is also a helpful tool in the diagnosis of achalasia. Endoscopy is a procedure in which a flexible tube with a camera on the end is swallowed. The camera provides direct visualization of the inside of the esophagus. Endoscopy is important because it excludes the presence of esophageal cancer, another serious disease of the esophagus that can obstruct the passage of food and dilate the esophagus.
A typical patient with achalasia has symptoms for approximately two years before the diagnosis finally is determined. The frequent delay in diagnosis is due to the mild and vague symptoms in the early stages of the disease that often do not cause the patient to seek medical attention. These symptoms include mild chest discomfort, indigestion, or slight difficulty with swallowing. As the disease progresses, more prominent chest pain, difficulty eating, regurgitation of food, weight loss, and breathing problems appear, which typically lead to testing and diagnosis.
Complications of achalasia include inflammation of the swallowing tube, called esophagitis, which is caused by the irritating food and fluids that collect and remain in the esophagus for prolonged periods of time. Of potential concern is the possibility that there is an increased occurrence of cancer of the esophagus in patients with achalasia. Some physicians feel that effective treatment of achalasia may reduce the risk for cancer, but this has not been proved.
Treatments for achalasia include oral medications, dilation or stretching of the lower esophageal sphincter, and surgery to cut the sphincter. A newer approach involves injection of botulinum toxin (Botox) into the sphincter to loosen the muscle.
Oral medications that help to relax the lower esophageal sphincter include groups of drugs called nitrates and calcium-channel blockers. Although some patients with achalasia have improvement of symptoms with medications, many experience side-effects of the medications. By themselves, medications taken by mouth are likely to provide only short-term and not long-term relief of the symptoms of achalasia.
The lower esophageal sphincter also may be treated directly. Dilation of the lower esophageal sphincter is done by passing an endoscope and then positioning a balloon within the lower esophageal sphincter. It starts inflating in order to stretch it and dilate balloon on the end. Sometimes more than one session is needed and the results can last for years.
A newer endoscopic technique is the injection of medicine called botulinum toxin (Botox) into the lower sphincter to weaken the muscle. Preliminary studies have shown that the use of Botox is safe, but the effect on the esophagus may be temporary, lasting only six months and additional Botox therapy may be necessary. Since Botox therapy is relatively new, it is not known how well such therapy will work over a period of many years.
Surgery is the most definitive treatment, but also the most invasive. The muscle at the lower esophageal sphincter is actually providing relief that is usually long lasting.
Points to Remember
• Achalasia is a rare disease of the muscle of the esophagus.
• The cause of achalasia is unknown.
• Common symptoms include difficulty swallowing and chest pain.
• Achalasia can be diagnosed by x-ray, endoscopy, or esophageal manometry.
• Achalasia may increase the risk of cancer of the esophagus.
• Treatments include oral medications, dilation or stretching of the esophagus, surgery, and injection of muscle-relaxing medicines directly into the esophagus.
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