Welcome to another e-newsletter from the Center for Digestive Health & Nutrition. Our physicians, nurse practitioner, and registered dietician provide this information to help improve awareness in matters of health and nutrition. Each issue - which now goes out to over 13,000 readers - focuses on a particular topic that we feel will be of interest.

As doctors we sometimes forget that the medical terms we take for granted may not be completely understood by our patients. One common area of confusion is the term hiatal hernia. Most adults have heard this phrase, but may not fully understand what it means. If you are not sure, read on...

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I am asked this question almost every day. Many adults have heard the phrase "hiatal hernia," but do not know exactly what it means. Actually it's quite simple. Between your chest and abdomen lies a flat muscular sheet called the diaphragm. Above this thin membrane lies your chest cavity which contains the heart and lungs. Below is the abdominal cavity which contains your stomach and intestines. Normally, your entire stomach organ lies below the diaphragm in the abdomen.

The esophagus or "food pipe," is the hollow muscular tube that transports food into your stomach. To reach your stomach, the esophagus must travel down through the center of your chest and enter the abdominal cavity through a small opening in the diaphragm called the hiatus.

Over time, body tissues sometimes sag and stretch. Occasionally, the hiatus opening widens. This allows the top portion of the stomach to slip upward into the chest cavity. In this circumstance, most of the stomach remains within the abdomen, but a portion sits above the diaphragm in the lower chest. That portion of the stomach which rises above the diaphragm is called a hiatal hernia. The name is derived from the fact that the stomach pushes, or herniates, through the hiatus. So a hiatal hernia is simply an abnormal displacement of part of the stomach upward into the chest cavity. This condition is quite common affecting over one in three adults. Most often, the hernia is small and there are no symptoms and may be discovered during an UGI barium x-ray of the stomach or a gastroscopy "scope" examination.

What Causes A Hiatal Hernia?
A hiatal hernia may occur when the diaphragmatic hiatus enlarges or weakens. The cause is not really known. It may be made worse by obesity, pregnancy, weightlifting, straining at stool, or just bad luck. There is no good evidence that a hiatal hernia is hereditary, but since it is so common, multiple family members may be affected.

Three Types of Hiatal Hernia
There are three types of hiatal hernia. The most common type is the simple sliding hiatal hernia. In this case, the herniated part of the stomach may slide up and down, into and out of the chest. A fixed hiatal hernia is most often associated with acid reflux. In this case, the upper part of the stomach is permanently caught up in the chest. The most serious type of hiatal hernia is a paraesophageal hiatal hernia. In this rare circumstance, part or all of the stomach is trapped in the chest cavity beside the esophagus. Most of these patients require surgery.

Acid Reflux
Another confusing term is "acid reflux." This refers to the backward splashing of stomach acid upward into the lower esophagus. At the bottom of the esophagus is a complex valve called the lower esophageal sphincter, or LES for short. This valve is normally closed tightly which prevents powerful stomach acid and partially digested food from rising up into the esophagus. When we swallow, the LES valve opens just long enough to allow the food to drop down into the stomach - and then quickly snaps shut protecting the delicate lining of the esophagus. When the LES malfunctions or weakens, acidic stomach contents can backsplash, or reflux, upward into the esophagus. Thus the term, acid reflux. In most cases, a weak LES is associated with a significant hiatal hernia.

The Enemy Within
It is amazing that deep within our body we constantly carry a pool of corrosive hydrochloric acid. When we eat a piece of meat, the acid within our stomach turns that meat into a liquid within a few hours - so our intestines can digest it. But, when you think about it, our stomach organ is also made out of "meat." Why doesn't that powerful acid eat right through our body? Fortunately, the walls of our stomach are lined with a protective acid-resistant mucous layer. In this way, acid never really touches the meat of the stomach wall and the enemy is contained. However, the esophagus lacks that protective layer and is quite susceptible to acid damage. The only protection for the esophagus is the LES. This "one-way valve" allows food to enter your stomach, but does not permit acid to rise upward. When this valve malfunctions, acid reflux occurs.

GERD
When acid reflux happens occasionally, one may experience a burning chest pain beneath the breastbone - called heartburn. Most adults experience simple heartburn occasionally - especially after a large or particularly spicy meal. Usually, a dose of antacid stops the problem. However, frequent episodes of acid reflux can damage the delicate lining of the esophagus. This condition is called GastroEsophageal Reflux Disease, or GERD.

Complications of GERD
Over time, untreated GERD can lead to complications such as painful esophageal ulcers which may come and go. Repeated episodes of ulceration can cause scarring and narrowing (stricture) of the esophagus which may make it difficult to swallow. Over a period of years, acid reflux may actually cause a transformation of the normal esophagus lining from normal esophagus cells to intestinal-type cells. This condition is termed Barrett's Esophagus after Dr. Norman R. Barrett, a distinguished London surgeon, who first described it in the 1950's. Unrecognized and untreated Barrett's Esophagus can develop into cancer of the esophagus, a deadly condition.

How Does Your Doctor Know?
If you experience frequent heartburn or problems swallowing, you should discuss this with your doctor. If your doctor feels that your symptoms may be due to a hiatal hernia and acid reflux, he/she can arrange simple tests to see what is wrong. These may include an Upper GI (UGI) barium x-ray or more commonly a more accurate direct evaluation with a gastroscopy "scope" examination. Once a diagnosis is made, your doctor may prescribe treatment. In most cases, it is NOT necessary to operate and repair a hiatal hernia. The problem is not the hernia itself, but rather the acid reflux that it causes. If the acid reflux can be controlled with dietary changes and medication, surgery is usually not needed.

Summary
A hiatal hernia is quite common and, in most cases, there are no symptoms. Many adults experience occasional heartburn from simple acid reflux. When acid reflux becomes frequent or severe, the esophagus may become damaged. Untreated damage can lead to serious complications. If you have heartburn more than twice a week on a regular basis or experience difficult or painful swallowing, you should discuss these symptoms with your physician. In most cases, simple measures or medication can eliminate the problem.

HIATAL HERNIA AND ACID REFLUX
These photos were taken from four different individuals during a gastroscopy "scope" examination. The first photo is normal with a tight LES and healthy esophagus lining. The second photo demonstrates a wide-open LES above a hiatal hernia "pouch." This opening allows acid reflux to occur. The third photo reveals GERD with severe ulceration of the lower esophagus due to longstanding acid reflux. The last photo is from an individual who has developed changes of Barrett's Esophagus from chronic untreated GERD and is at increased risk of esophageal cancer.