The esophagus is a tube that connects the back of the mouth to the stomach. Abnormalities of the esophagus generally fall into one of four categories:
- Structural Abnormalities
- Motility Disorders
- Inflammatory Disorders
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 inches (25 cm) long. It 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 to 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 about an inch or so above the point where the esophagus enters the stomach. The LES, when functioning properly, contracts to keep the contents of the stomach from back flowing into the lower end of the esophagus.
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.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.
Many more people have these defects than develop symptoms and seek medical care; so the presence of these asymptomatic structural defects is found only when other esophageal or stomach treatments are being done or during autopsies. Obesity and advancing age are thought to be contributing factors in developing symptoms.
Achalasia symptoms include difficulty swallowing, which usually develops slowly, often 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 Chaga’s disease, a disease rare in North America, but common in Central and South America.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 the naturally occurring bacteria in the esophagus and allow fungi, which are normally present in the digestive tract, to grow unchecked.
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 patient drinks 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 detect Schatzki rings.
Upper gastrointestinal endoscopy is often used in conjunction with a barium swallow to diagnose esophageal disorders. In an endoscopy, a thin, fiber optic tube with a tiny camera is inserted into the esophagus. This allows your physician to see the lining of the esophagus. Endoscopes are equipped to allow your physician to take samples (biopsies) of any area that may appear pre-cancerous or cancerous, so they can be tested.
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 to 15 percent of the time. CT scans can be used in conjunction with chest x-rays for diagnosis.