Heartburn is one symptom of acid reflux, which occurs when acidic gastric juices leak from the stomach into the esophagus, causing inflammation and damage to its lining. The diaphragm, which separates the chest from the abdomen and is located near the base of the esophagus, is the main muscle that controls breathing. But it also plays an important role in healthy digestion. Problems with the diaphragm can contribute to acid reflux.
The Diaphragm's Role in Reflux
The diaphragm has a complex role in helping to prevent acid reflux. To reach the stomach, the lower esophagus passes through a hole, or "hiatus," in the diaphragm. This lower portion of the esophagus also contains a ring of muscle that normally closes tightly to prevent acidic digestive juices from leaking back out of the stomach. The diaphragm plays a complicated part in assisting this muscle -- the lower esophageal sphincter, or LES -- to seal tightly enough to prevent stomach contents from "refluxing" back up into the esophagus.
Hiatal hernia is a common abnormality of the diaphragm that may affect acid reflux, triggering symptoms of heartburn. It occurs when the stomach protrudes, or herniates, upward into the chest cavity because the esophagus opening in the diaphragm -- the hiatus -- has become enlarged. This allows the stomach to move up into the chest instead of remaining in the abdomen. Multiple types of hiatal hernia exist. In a “sliding hiatal hernia,” the junction between stomach and esophagus is able to slide above the diaphragm. According to the "Merck Manual Professional Version," this type of hernia may show up incidentally on X-rays in as much as 40 percent of the population. In a paraesophageal hiatal hernia, the point where the stomach joins the esophagus remains in its normal place, but part of the stomach herniates into the chest, resting on one side of the esophagus. Hiatal hernias may be caused by injury, pregnancy, obesity, heavy lifting, surgery, genetic factors or aging.
Heartburn and Hiatal Hernias
According to the "Merck Manual Professional Version," fewer than 50 percent of people with hiatal hernias have acid reflux disease. In fact, most people with sliding or paraesophageal hernias have no symptoms at all. But when a person has a hiatal hernia and the ower esophageal sphincter muscle doesn't work properly, heartburn and other symptoms may result. Hiatal hernias also may prevent acid from clearing from the esophagus after reflux by creating a pocket of gastric juice that lingers in the esophagus despite swallowing, potentially leaving a bitter or acidic taste in the mouth. Regurgitation may also be a problem because connective tissues surrounding the junction between stomach and esophagus may lose their tautness, enlarging the opening and allowing larger amounts of liquid and gas to pass through. Hiatal hernias may also increase the frequency of acid refluxing into the esophagus.
When acid reflux is chronic and severe, it may be diagnosed as gastroesophageal disease, or GERD. Treatment for hiatal hernia-related GERD depends on the primary symptom. Heartburn can usually be controlled with drugs called proton-pump inhibitors, or PPIs, that block stomach acid production. These are available both over the counter and in prescription strength under names like omeprazole (Prilosec), lansoprazole (Prevacid) and esomeprazole (Nexium). Regurgitation, however, may require surgical repair of the hiatal hernia. An anti-reflux surgery called a Nissen fundoplication may also be called for if the LES fails to return to normal function by forming a tight seal through other means. The procedure involves wrapping the upper part of the stomach around the lower esophagus to reconstruct the LES.
Warning Signs of Hiatal Hernia
Sliding hiatal hernias usually have no symptoms, but chest pain and other reflux symptoms can occur. A paraesophageal hiatal hernia is also usually asymptomatic, but unlike a sliding hiatus hernia, it may become trapped and strangulate, causing extreme pain. Though rare, bleeding or a massive hemorrhage is possible with either type. If you are experiencing persistent heartburn, regurgitation, chest or upper abdominal pain or sour taste, discuss your symptoms with your healthcare provider.