(Cardiospasm; Esophageal Aperistalsis; Megaesophagus)
(See also Overview of the Esophagus.)
Achalasia is a disorder in which the rhythmic contractions of the esophagus (called peristalsis) are absent or impaired, the lower esophageal sphincter does not relax normally, and the resting pressure of the lower esophageal sphincter is increased.
This cause of this disorder usually is not known, but it may occur after exposure to some viruses.
The main symptom of achalasia is difficulty swallowing.
The diagnosis is based on results of manometry and barium swallow x-rays.
Treatment is aimed at relieving symptoms by dilating the lower esophageal sphincter with a balloon or cutting the muscle fibers of the sphincter, and sometimes by injecting botulinum toxin.
The esophagus is the hollow tube that leads from the throat (pharynx) to the stomach. The lower esophageal sphincter is the ring of muscle that holds the bottom of the esophagus closed so that food and stomach acid do not flow back up the esophagus. When people swallow, this sphincter normally relaxes to allow food into the stomach.
Achalasia may occur at any age but usually begins, almost unnoticed, between the ages of 20 and 60 and then progresses gradually over many months or years.
Achalasia results from a malfunction of the nerves (called denervation) controlling the rhythmic contractions of the esophagus. The cause of the denervation is not known, but viral and autoimmune causes are suspected. Certain tumors may cause an achalasia–like disorder either by directly narrowing (constricting) the lower esophageal sphincter or by infiltrating the nerves of the esophagus. Chagas disease, an infection that causes the destruction of clusters of nerve cells (autonomic ganglia), may also result in achalasia.
The tight lower esophageal sphincter causes the part of the esophagus above it to enlarge greatly. This enlargement contributes to many of the symptoms. Difficulty swallowing (dysphagia) both solids and liquids is the main symptom. Although less common, chest pain may occur during swallowing or for no apparent reason. About one third of people who have achalasia spit up (regurgitate) undigested food. If spitting up occurs when people are sleeping, they may inhale food into their lungs, which can cause coughing, infection of the airways, bronchiectasis, or aspiration pneumonia.
Mild to moderate weight loss also occurs. When people have significant weight loss, especially older people whose symptoms of dysphagia developed rapidly, doctors consider and usually look for a tumor at the gastroesophageal junction (the place where the esophagus connects to the stomach).
Doctors usually insert a small tube into the esophagus to take pressure measurements of the esophagus and lower esophageal sphincter (esophageal manometry). Often, doctors examine the esophagus through a flexible viewing tube (esophagoscopy). During an esophagoscopy, the doctor may do a biopsy (removal of tissue samples for examination under a microscope) to make sure the symptoms are not caused by cancer at the lower end of the esophagus.
X-rays of the esophagus taken while the person is swallowing barium (a barium swallow) show the normal rhythmic contractions of the esophagus are missing. The esophagus is widened, usually only moderately but occasionally to enormous proportions, but is narrow at the lower esophageal sphincter.
Some disorders, such as cancer at the gastroesophageal junction, can cause symptoms similar to achalasia, so doctors may do additional tests to rule out these other disorders. Cancer at the gastroesophageal junction can be diagnosed by computed tomography (CT) of the chest and abdomen or by an endoscopic ultrasound (an ultrasound probe on the tip of an endoscope is passed through the mouth into the stomach).
No treatment restores peristalsis of the esophagus. The aim of treatment is to relieve symptoms by decreasing pressure in the lower esophageal sphincter.
There are two main treatment options for relieving the symptoms of achalasia that are effective and have similar outcomes. The first is called balloon dilation. This option involves dilating the sphincter mechanically by inflating a large balloon inside it. This procedure helps over 85% of the time, but repeated dilations may be needed. In fewer than 2% of people with achalasia, the esophagus ruptures during the dilation procedure. Esophageal rupture leads to severe inflammation in the chest outside the esophagus (mediastinitis) and, in rare cases, is fatal if not treated appropriately. Immediate surgery is needed to close the rupture in the wall of the esophagus.
The second treatment option is called myotomy. This option involves surgery to cut the muscle fibers in the lower esophageal sphincter. The procedure is usually done with a laparoscope or, less commonly, with a thoracoscope. It can also be done with an endoscope. Myotomy is also successful over 85% of the time.
After myotomy, about 15% to up to 30% of people have backflow of acid (gastroesophageal reflux) into the esophagus. A procedure to prevent backflow of acid from the stomach (called a fundoplication) is usually done at the same time as myotomy.
As an alternative to balloon dilation or myotomy, a doctor may inject botulinum toxin into the lower esophageal sphincter. This therapy is almost as effective as balloon dilation, but relief may last only 6 months to 1 year.
Certain drugs can help relax the sphincter. They have limited effectiveness but may prolong the time between balloon dilations or botulinum toxin injections. The most common drugs are nitrates (for example, isosorbide dinitrate placed under the tongue before meals) or calcium channel blockers (for example, nifedipine).