The movement of food from mouth to stomach requires normal and coordinated action of the mouth and throat, propulsive waves of the esophagus, and relaxation of the sphincters. A problem with any of these functions can cause difficulty swallowing (dysphagia), regurgitation (the spitting up of food from the esophagus or stomach without nausea or forceful contractions of abdominal muscles), vomiting, or aspiration of food (sucking food into the airways when inhaling).
Achalasia (also called cardiospasm, esophageal aperistalsis, or megaesophagus) is a disorder in which the rhythmic contractions of the esophagus are greatly decreased, the lower esophageal sphincter does not relax normally, and the resting pressure of the lower esophageal sphincter is increased.
Achalasia results from a malfunction of the nerves controlling the rhythmic contractions of the esophagus. The cause of the nerve malfunction is not known, but a viral cause is suspected. Certain tumors may cause achalasia either by directly constricting (narrowing) the lower esophageal sphincter or by infiltrating the nerves of the esophagus. Chagas' disease, which causes the destruction of clusters of nerve cells (autonomic ganglia), may also result in achalasia.
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. 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 both solids and liquids is the main symptom. Other symptoms may include chest pain; regurgitation of the bland, nonacidic contents of the enlarged esophagus; and coughing at night. Although uncommon, chest pain may occur during swallowing or for no apparent reason. About one third of people who have achalasia regurgitate undigested food while sleeping. They may inhale food into their lungs, which can cause coughing, a lung abscess, infection of the airways, bronchiectasis, or aspiration pneumonia. Undigested food typically remains in the esophagus. 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 look for a tumor at the gastroesophageal junction (the place where the esophagus connects to the stomach).
X-rays of the esophagus taken while the person is swallowing barium (a barium swallow—see see X-Ray Studies) show an absence of the normal rhythmic waves of muscular contractions (peristalsis). The esophagus is widened, usually only moderately but occasionally to enormous proportions, but is narrow at the lower esophageal sphincter.
Doctors usually also insert a small tube into the esophagus to take pressure measurements of the contractions (esophageal manometry—see see Manometry). Often, doctors examine the esophagus through a flexible viewing tube (esophagoscopy—see see Endoscopy). During an esophagoscopy, the doctor performs 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.
Achalasia that is caused by cancer at the gastroesophageal junction can be diagnosed by computed tomography (CT) of the chest and abdomen or by an endoscopic ultrasound (a tiny ultrasound probe on the tip of an endoscope that is passed through the mouth into the stomach).
No treatment restores peristalsis. The aim of treatment is to relieve symptoms by decreasing pressure in the lower esophageal sphincter. Nitrates (for example, nitroglycerin placed under the tongue before meals) or calcium channel blockers (for example, nifedipine) are of limited effectiveness but may delay the need for dilation by helping to relax the sphincter.
Dilation widens the sphincter mechanically—for example, by inflating a large balloon inside it. This procedure helps about 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.
As an alternative to mechanical dilation, a doctor may inject botulinum toxin into the lower esophageal sphincter. This therapy is as effective as mechanical dilation with balloons. Botulinum toxin seems to be successful in providing sustained symptom relief for 70 to 80% of people, but the relief may last only 6 months to 1 year.
If dilation or botulinum toxin therapy does not work, a surgical procedure to cut the muscular fibers in the lower esophageal sphincter (myotomy) is usually performed. The procedure can be done with a laparoscope (see see Laparoscopy) or a thoracoscope (see see Thoracoscopy). This procedure is successful about 85% of the time. A procedure (called a fundoplication) to prevent backflow of acid from the stomach (gastroesophageal reflux or GERD) is usually performed during the same surgery. About 15% of people experience episodic backflow of acid (reflux) after surgery.
Esophageal pouches (diverticula) are abnormal protrusions from the esophagus that in rare cases cause swallowing difficulties and regurgitation (the spitting up of food from the esophagus or stomach without nausea or forceful contractions of abdominal muscles).
There are several types of esophageal diverticula. Each has a different cause, but probably all are related to uncoordinated swallowing and muscle relaxation. Most of these diverticula are associated with motility disorders of the esophagus, such as esophageal spasm and achalasia.
A pharyngeal pouch or Zenker's diverticulum is probably caused by an incoordination between movement of food out of the mouth and relaxation of the cricopharyngeal muscle. This diverticulum can fill with food, which may be regurgitated when the person bends over or lies down. This may also cause food to be inhaled into the lungs during sleep, resulting in aspiration pneumonia. Rarely, the pouch enlarges and causes swallowing difficulty and sometimes a swelling in the neck.
A midesophageal pouch or traction diverticulum is caused by traction from inflamed lesions located in the chest outside the esophagus (mediastinum) or, secondarily, by esophageal movement (motility) disorders. A traction diverticulum rarely causes symptoms, but the underlying disorder may.
An epiphrenic pouch or diverticulum occurs just above the diaphragm and usually accompanies a motility disorder (such as achalasia or esophageal spasm). An epiphrenic diverticulum rarely causes symptoms, but the underlying disorder may.
Diagnosis and Treatment
All diverticula can be diagnosed with a videotaped barium swallow.
Treatment is not usually needed. If symptoms are severe, however, the pouch can be removed surgically. Diverticula associated with motility disorders require treatment of the underlying disorder. For example, if a Zenker's diverticulum is caused by an abnormally functioning cricopharyngeal muscle, a doctor can cut the muscle (myotomy) when removing the Zenker's diverticulum. When esophageal spasm or achalasia is present, treatment of sphincter tightness may be needed.
Esophageal spasm (also called spastic pseudodiverticulosis, rosary bead or corkscrew esophagus, or symptomatic diffuse esophageal spasm) is a disorder of the propulsive movements (peristalsis) of the esophagus.
In this disorder, the normal propulsive contractions that move food through the esophagus are replaced periodically by nonpropulsive contractions or excessive muscular contractions (hyperdynamia). In 30% of people with this disorder, the lower esophageal sphincter opens and closes abnormally. The exact cause is not known but is suspected to be a nerve defect.
Muscle spasms throughout the esophagus typically are felt as chest pain under the breastbone coinciding with difficulty in swallowing liquids (especially those that are very hot or cold) and solids. Pain also occurs at night and may be severe enough to awaken a person. Esophageal spasm also may cause severe pain without swallowing difficulty. This pain, often described as a squeezing pain under the breastbone, may accompany exercise or exertion, making it difficult for a doctor to distinguish it from angina (chest pain stemming from heart disease). Over many years, this disorder may evolve into achalasia (see see Achalasia), a disorder in which the rhythmic contractions of the esophagus are greatly decreased. Some people have symptoms that combine those of achalasia and diffuse esophageal spasm. One such combination of symptoms has been called vigorous achalasia. It features both food retention, which can lead to aspiration, as well as severe chest pain from diffuse esophageal spasm.
X-rays taken while the person swallows a barium drink (a barium swallow—see see X-Ray Studies) may show that liquid barium does not move normally down the esophagus and that contractions of the esophageal wall are uncoordinated and do not propel the barium. Pressure measurements by manometry (a test in which a tube placed in the esophagus measures the pressure of contractions—see see Manometry) provide the most sensitive and detailed analysis of the spasms.
Esophageal spasm is often difficult to treat. Calcium channel blockers such as nifedipine may relieve the symptoms by relaxing the muscles of the esophagus. Sometimes, injecting botulinum toxin into the muscles of the esophagus is helpful. Other drugs such as nitroglycerin, long-acting nitrates, and drugs with anticholinergic effects (such as dicyclomine) are less successful. Sometimes people need strong analgesics. In many cases, a narrowing is treated by inflating a balloon inside the esophagus or by inserting bougies (progressively larger dilators) to dilate the esophagus. In rare cases, if other less radical forms of treatment are not effective, a surgeon may cut the muscle layer along the full length of the esophagus (surgical myotomy).
Propulsion Disorders of the Throat
Propulsion disorders of the throat can cause trouble moving food from the upper part of the throat into the esophagus. Such problems occur most often in people who have disorders of the throat muscles or the nerves that serve them. The most common cause is stroke. Dermatomyositis, scleroderma, myasthenia gravis, muscular dystrophy, polio, pseudobulbar palsy, Parkinson's disease, and amyotrophic lateral sclerosis (Lou Gehrig's disease) all can affect the throat muscles or nerves. Difficulty swallowing may also result from the use of a phenothiazine (a class of antipsychotic drug), because these drugs can impair the normal function of the throat muscles. People with a propulsion disorder of the throat often regurgitate food through the back of the nose or inhale it into the windpipe (trachea), which causes them to cough.
In cricopharyngeal incoordination, the upper esophageal sphincter (cricopharyngeal muscle) remains closed, or it opens in an uncoordinated way. An abnormally functioning sphincter may allow food to repeatedly enter the windpipe and lungs, which may lead to recurring lung infections and eventually to chronic lung disease. A surgeon can cut the sphincter so that it is permanently relaxed. If left untreated, the condition may lead to the formation of a diverticulum (see see Esophageal Pouches), a pouch formed when the lining of the esophagus pushes outward and backward through the cricopharyngeal muscle.
Last full review/revision October 2007 by Michael C. DiMarino, MD