The main function of the esophagus is to move food from the back of the mouth to the stomach. The adult esophagus is about 10 in (25 cm) long. It is consists of a layer of cells that secretes mucus and two layers of muscle, one circular and one longitudinal. This combination of muscles allows the esophagus to contract and propel food from the mouth the stomach. This rhythmic contraction is called peristalsis. At the end of the esophagus nearest the mouth is a ring of muscle called the upper esophageal sphincter (UES). A similar muscular ring called the lower esophageal sphincter (LES) is found 1–1.5 in (2–4 cm) above the point where the esophagus enters the stomach. The LES contracts to prevent the contents of the stomach from backflowing into the lower end of the esophagus.

Structural abnormalities of the esophagus can be either congenital or acquired. Congenital abnormalities occur in about 1 of every 3,000–5,000 births. The two most common congenital esophageal abnormalities are esophageal atresia (EA) and tracheoesophageal fistula (TEF).

EA is a condition in which the esophagus is interrupted and the portion of the tube near the mouth is not connected to the portion that goes into the stomach. Usually the upper part of the tube ends in a blind pouch. This creates a life-threatening condition for the newborn who is unable to eat.

TEF is a condition in which the esophagus is connected to the trachea (windpipe). The trachea and the esophagus lie parallel to each other in the neck. Sometimes during fetal development, a connection called a fistula develops between these two tubes. This allows food to enter the trachea and be inhaled into the lungs causing a life-threatening condition called aspiration pneumonia. Often TEF and EA are present in the same infant. Both these conditions must be surgically corrected for the infant to survive.

Other, less common congenital structural abnormalities include webs, stenosis, cysts, and diverticula. Webs are thin membranes that lie across the esophagus and cause a partial obstruction. Stenosis is the abnormal reduction in the diameter of the esophagus due to thickening of the esophageal wall Diverticula are pouches of tissue that extend off the esophagus. Both diverticula and stenosis can be either congenital or acquired later in life.

Acquired structural abnormalities of the esophagus include Schatzki ring and hiatal hernia. Schatzki ring, sometimes called a lower esophageal ring, is a circular band of tissue located where the esophagus empties into the stomach. This ring is found in 6–14% of individuals, and for most people the presence of this ring does not create symptoms. Schatzki ring is found equally in all races and in both men and women. Schatzki rings that cause symptoms usually occur in middle age individuals. The ring can cause intermittent problems swallowing food or food impaction where the esophagus enters the stomach.

The esophagus passes a gap in the diaphragm called the diaphragmatic hiatus in order to reach the stomach. Hiatal hernia (also called hiatus hernia) is a condition that occurs when a portion of the stomach pushes up through this gap next to the esophagus. Although a hiatus hernia is not a direct structural abnormality of the esophagus, it is associated with gastroesophageal reflux disease (GERD) or heartburn in which the acidic stomach contents backflow into the lower part of the esophagus and erode the cell lining. Hiatal hernia is very common and often causes no symptoms. It is treated as a separate entry.

Lacerations, tears and ruptures of the esophagus, known as Mallory-Weiss syndrome and Boerhaave syndrome, are life-threatening disorders. Mallory-Weiss syndrome usually occurs in alcoholics. In both conditions, tears result from vomiting and retching. The resulting bleeding creates a medical emergency that can be fatal.

Motility abnormalities create difficulty in swallowing, called dysphagia. Dysphagia is a symptom of several esophageal motility disorders as well as several obstructive disorders such as esophageal webs or Schatzki ring.

Achalasia is an esophageal motility disorder caused by uncoordinated contractions of the two muscular layers that make up the esophagus. Because muscular contractions are disorganized, peristalsis and the orderly movement of food down the esophagus does not occur. In addition, with achalasia the lower esophageal sphincter remains contracted when food is present in the esophagus which prevents the food from entering the stomach. This causes the esophagus to bulge above the LES, a condition called megaesophagus.

Achalasia is caused by destruction of some of the nerve cells that control muscular contraction of the esophagus. This disorder generally begins in young adults and becomes progressively worse as the individual ages. Individuals with achalasia also have a higher risk of developing esophageal cancer at an earlier than usual age.

Individuals can also develop esophageal motility disorders secondary to other muscle diseases. Scleroderma is a disorder in which smooth muscle begins to atrophy. The smooth muscle in the esophagus can be affected just like other smooth muscle in the body, making swallowing difficult. Scleroderma esophagus is also associated with GERD and increased risk of cancer of the esophagus. Other conditions such as diabetes mellitus, alcoholism, and some psychiatric disorders can also produce secondary esophageal motility disorders.

Inflammatory esophageal disorders fall under the general name of esophagitis. Esophagitis causes the esophagus to become swollen and the lining of the esophagus becomes eroded and sore. It is present in about 5% of the population in the United States. There are four main types of esophagitis: reflux, infection, corrosive, and radiation. Reflux esophagitis is caused by GERD when the lower esophageal sphincter does not close tightly and the acidic contents of the stomach enter esophagus. GERD is common and is treated in depth in a separate entry. Infectious esophagitis can be caused fungal, viral, or bacterial infections. Infectious esophagitis occurs frequently in individuals with compromised immune systems, such as those with AIDS or leukemia. Corrosive esophagitis occurs when an individual either intentionally or accidentally swallows harsh chemicals such as lye. Radiation esophagitis is a complication of radiation treatments for cancer of the esophagus or lung.

Barrett's esophagus is a pre-cancerous condition which has a high risk of developing into esophageal cancer. It is found most commonly in white males in their 50s and 60s and is usually associated with years of chronic GERD.

Cancers of the esophagus tend to be aggressive and have poor outcomes. Adenocarcinoma is the primary cancer of the esophagus. Esophageal cancers are treated in detail in a separate entry.

The causes of esophageal disorders depend on the type of disorder. Congenital defects are caused by errors in development. It is not clear why some structural disorders, such as Schatzki ring and hiatal hernia, occur. Many more people have these defects than develop symptoms or seek medical care, so that the presence of these asymptomatic structural defects is found only during autopsies. Other individuals develop symptoms that require medical attention. Obesity and advancing age are thought to be contributing factors in developing symptoms.

Achalasia is caused by death of nerve cells that control the muscles that make peristalsis possible. These nerve cells are destroyed by T cells that are part of the body's immune system. It is not clear what triggers these T cells to attack inappropriately. Difficulty swallowing develops slowly, usually beginning in young adults, although the disorder can occur in children. As nerve control is lost, the LES fails to relax, preventing food from entering the stomach. As a result, the lower part of the esophagus becomes stretched creating a condition called megaesophagus. At night, food is often regurgitated and can be inhaled into the lungs, creating the risk of aspiration pneumonia. Achalasia can also be caused by Chagas' disease, a disease rare in North America, but common in Central and South America. Individuals with achalasia are also at higher risk to develop esophageal cancer, esophageal infections, and esophageal rupture.

Inflammatory esophagitis is most often caused by GERD. Infectious esophagitis can be caused by fungi, usually Candida albicans, bacteria, or viruses. Fungal infections usually occur in individuals who have diabetes, a weakened immune system, or who are taking antibiotics. Antibiotics change the balance of naturally occurring bacteria in the esophagus and allow fungi, which are normally present in the digestive tract, to grow unchecked. The most common causes of viral esophagitis are cytomegalovirus (CMV) and Herpes simplex. These are usually opportunistic infections in individuals with HIV/AIDS.

Corrosive esophagitis is usually caused by swallowing harsh chemicals, but it can also be caused by certain medications. Radiation esophagus is a side effect of radiation therapy for cancer.

EA and TEF can sometimes be diagnosed in fetal ultrasounds before birth. If not, these defects become obvious soon after birth, because the infant is unable to eat. The inability to pass a tube from the mouth to the stomach is a definite diagnosis for EA. TEF can be detected through x-rays.

A barium swallow x ray with video is the basic method of diagnosing most esophageal disorders. For a barium swallow x ray, the individual drinks a barium, a material that coats the esophagus and shows up on x-ray film. A video camera records the passage of the barium down the esophagus in order to detect swallowing disorders or pockets and pouches (diverticula) bulging from the esophagus. A barium swallow is also used to detect Schatzki rings.

Upper gastrointestinal endoscopy is often used in conjunction with a barium swallow to diagnose esophageal disorders. In an endoscopy, a thin, fiberoptic tube with a tiny camera is inserted into the esophagus. This allows the physician to see the lining of the esophagus. Endoscopes are equipped to take samples (biopsies) of any areas that may appear pre-cancerous or cancerous or to collect samples to test for the organism causing infectious esophagitis.

GERD can often be diagnosed from symptoms such as heartburn and regurgitation. Mallory-Weiss tears and Boerhaave syndrome are difficult to diagnose. Individuals with these disorders are often severely ill and have intense chest pain and vomiting, however chest x rays are normal 10–15% of the time. CT scans may be used in conjunction with chest x rays.

Surgery is the only treatment for EA and TEF. It is done as soon as possible, based on the condition of the infant and any other birth defects that may be present that could affect the surgery.

Schatzki rings and hiatal hernias often cause no or mild symptoms and need no treatment. In severe cases, Schatzki rings are treated with bougienage. In this treatment, a series of tubes of ever-increasing diameter are inserted through the esophagus to stretch the ring. Stretching can also be done with balloon dilation. Surgery is done when no other treatment succeeds in relieving symptoms. Large hiatal hernias can be repaired surgically, but often there is not need for treatment. GERD accompanies many hiatal hernias. GERD can be treated with drugs to block acid production in the stomach (H2 blockers or proton pump inhibitors) and changes in diet. In severe cases of GERD stomach surgery may be necessary.

Mallory-Weiss syndrome and Boerhaave syndrome are medical emergencies. The individual is stabilized and the tear or rupture is repaired surgically. The chance of infection (sepsis) is high, so individuals are admitted to intensive care and do not take any food or liquid by mouth for 7–10 days. Hospital stays can last months, and repeated tears are possible.

Achalasia is treated with drugs that relax the smooth muscle and allow the LES to relax and open. When this fails, surgery to may be needed. Individuals that are not good candidates for surgery (the elderly or frail) may be treated by injecting botulinum toxin (botox) into the LES to prevent it from closing. The disadvantage of this treatment is its expense and the fact that more than one injection is needed.

Infectious esophagitis is treated by treating the underlying cause of the disease with antifungal, antiviral or antibiotic medications. These can be given either by mouth or intravenously (IV) depending on the severity of the disease.

Malignancies are treated with chemotherapy and radiation. See the entry on esophageal cancer for specific details.

The outcome of treatment depends on the type of disorder, severity, age, and general health of the individual. EA and TEF surgeries are often successful, but infants born with these conditions frequently have other congenital abnormalities that compromise their health.

When needed, treatment for Schatzki rings produces relief of symptoms, but almost always has to be repeated periodically.

Mallory-Weiss and Boerhaave syndromes are often fatal. Thirty to fifty percent of individuals die from these disorders even if they are diagnosed promptly. If diagnosis is delayed, the death rate can be as high as 90%.

Achalasia and scleroderma esophagus are progressive diseases that need continued therapy. They frequently lead to serious weight loss and malnutrition.

The outcome for treatment of inflammatory esophagitis depends almost entirely on the success of treating the underlying cause. Where individuals have a weakened immune system, infectious esophagitis can be an ongoing problem. When inflammatory esophagitis is caused by GERD, treatment along with lifestyle modification is usually successful in providing relief.

Esophageal cancers are aggressive and have generally poor outcomes.

Many symptoms of esophageal disorders can be prevented or alleviated by lifestyle changes that include:

• weight loss to control obesity
• eating slowly and chewing food well
• eating smaller and more frequent meals
• not eating several hours before going to bed
• limiting the use of alcohol and caffeine