Achalasia

Achalasia 

Definition

Achalasia is a disorder of the esophagus that prevents normal swallowing.

Description

Achalasia affects the esophagus, the tube that carries swallowed food from the back of the throat down into the stomach. A ring of muscle called the lower esophageal sphincter encircles the esophagus just above the entrance to the stomach. This sphincter muscle is normally contracted to close the esophagus. When the sphincter is closed, the contents of the stomach cannot flow back into the esophagus. Backward flow of stomach contents (reflux) can irritate and inflame the esophagus, causing symptoms such as heartburn. The act of swallowing causes a wave of esophageal contraction called peristalsis. Peristalsis pushes food along the esophagus. Normally, peristalsis causes the esophageal sphincter to relax and allow food into the stomach. In achalasia, which means "failure to relax," the esophageal sphincter remains contracted. Normal peristalsis is interrupted and food cannot enter the stomach.

Causes and symptoms

Causes

Achalasia is caused by degeneration of the nerve cells that normally signal the brain to relax the esophageal sphincter. The ultimate cause of this degeneration is unknown. Autoimmune disease or hidden infection is suspected.

Symptoms

Dysphagia, or difficulty swallowing, is the most common symptom of achalasia. The person with achalasia usually has trouble swallowing both liquid and solid foods, often feeling that food "gets stuck" on the way down. The person has chest pain that is often mistaken for angina pectoris (cardiac pain). Heartburn and difficulty belching are common. Symptoms usually get steadily worse. Other symptoms may include nighttime cough or recurrent pneumonia caused by food passing into the lower airways.

Diagnosis

Diagnosis of achalasia begins with a careful medical history. The history should focus on the timing of symptoms and on eliminating other medical conditions that may cause similar symptoms. Tests used to diagnose achalasia include:

Treatment

The first-line treatment for achalasia is balloon dilation. In this procedure, an inflatable membrane or balloon is passed down the esophagus to the sphincter and inflated to force the sphincter open. Dilation is effective in about 70% of patients.

Three other treatments are used for achalasia when balloon dilation is inappropriate or unacceptable.

Prognosis

Most patients with achalasia can be treated effectively. Achalasia does not reduce life expectancy unless esophageal carcinoma develops.

Prevention

There is no known way to prevent achalasia.

Resources

Books

Grendell, James H., Kenneth R. McQuaid, and Scott L. Friedman, editors. Current Diagnosis and Treatment in Gastroenterology. Stamford: Appleton & Lange, 1996.

Key terms

Botulinum toxin — Any of a group of potent bacterial toxins or poisons produced by different strains of the bacterium Clostridium botulinum. The toxins cause muscle paralysis.

Dysphagia — Difficulty in swallowing.

Endoscopy — A test in which a viewing device and a light source are introduced into the esophagus by means of a flexible tube. Endoscopy permits visual inspection of the esophagus for abnormalities.

Esophageal manometry — A test in which a thin tube is passed into the esophagus to measure the degree of pressure exerted by the muscles of the esophageal wall.

Esophageal sphincter — A circular band of muscle that closes the last few centimeters of the esophagus and prevents the backward flow of stomach contents.

Esophagomyotomy — A surgical incision through the muscular tissue of the esophagus.

Esophagus — The muscular tube that leads from the back of the throat to the entrance of the stomach.

Peristalsis — The coordinated, rhythmic wave of smooth muscle contraction that forces food through the digestive tract.

Reflux — An abnormal backward or return flow of a fluid.

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achalasia /ach·a·la·sia/ (ak?ah-la´zhah) failure to relax of smooth muscle fibers at any junction of one part of the gastrointestinal tract with another, especially failure of the esophagogastric sphincter to relax with swallowing, due to degeneration of ganglion cells in the wall of the organ.

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ach·a·la·sia (k-lzh)

n.

The failure of a ring of muscle fibers, such as a sphincter, to relax.

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achalasia

failure to relax of the smooth muscle fibers of the gastrointestinal tract at any junction of one part with another; especially failure of the lower esophagus to relax with swallowing, due to an abnormality of innervation. Called also cardiospasm. See also megaesophagus.

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cricoesophageal achalasia

failure of the cranial esophageal sphincter to relax during swallowing to accommodate the approaching bolus. Gagging, nasal regurgitation and aspiration result. Called also cricoesophageal incoordination.

cricopharyngeal achalasia

is motor dysfunction of the cricopharyngeal sphincter in which a failure of relaxation prevents the bolus from entering the esophagus during swallowing. Called also cricopharyngeal dysphagia.

esophageal achalasia

see megaesophagus.

pyloric achalasia

failure of the pylorus to open in neonates so that distention of the stomach occurs and causes continuous vomiting. This may be reflex in response to local ulceration, e.g. in young calves, or be a congenital defect.

reticulo-omasal sphincter achalasia

is probably a factor in the development of the gut stasis in bovine vagal indigestion with onward passage of ingesta obstructed at the exit from the rumenoreticulum. Results in rumen distention and frothiness of contents.