WHAT IS GASTROESOPHAGEAL REFLUX?
When we eat, food is carried from the mouth to the stomach through the esophagus, a tube-like structure that is approximately 10 inches long and 1 inch wide in adults. The esophagus is made of tissue and muscle layers that expand and contract to propel food to the stomach through a series of wave-like movements called peristalsis.
At the lower end of the esophagus, where it joins the stomach, there is a circular ring of muscle called the lower esophageal sphincter (LES). After swallowing, the LES relaxes to allow food to enter the stomach and then contracts to prevent the back-up of food and acid into the esophagus. However, sometimes the LES is weak or becomes relaxed because the stomach is distended, allowing liquids in the stomach to wash back into the esophagus. This happens occasionally in all individuals. Most of these episodes occur shortly after meals, are brief, and do not cause symptoms. Normally, acid reflux should occur only rarely during sleep.
Acid reflux — Acid reflux becomes gastroesophageal reflux disease (GERD) when it causes bothersome symptoms or injury to the esophagus. The amount of acid reflux required to cause GERD varies. In general, damage to the esophagus is more likely to occur when acid refluxes frequently, the reflux is very acidic, or the esophagus is unable to clear away the acid quickly. The most common symptoms associated with acid reflux are heartburn, regurgitation, chest pain, and trouble swallowing. The treatments of GERD are designed to prevent one or all of these symptoms from occurring.
Hiatus hernia — The diaphragm is a large flat muscle at the base of the lungs that contracts and relaxes as a person breathes in and out. The esophagus passes through an opening in the diaphragm called the diaphragmatic hiatus before it joins with the stomach. Normally, the diaphragm contracts, which improves the strength of the LES, especially during bending, coughing, or straining. If there is a weakening in the diaphragm muscle at the hiatus, the stomach may be able to partially slip through the diaphragm into the chest, forming a sliding hiatus hernia.
The presence of a hiatus hernia makes acid reflux more likely. A hiatus hernia is more common in people over age 50. Obesity and pregnancy are also contributing factors. The exact cause is unknown but may be related to the loosening of the tissues around the diaphragm that occurs with advancing age. There is no way to prevent a hiatus hernia.
Information reviewed by Dr. Zitomer, board-certified gastroenterologist at Digestive Health Specialists.