What is a hiatal hernia (definition)?
The esophagus connects the throat to the stomach. It passes through the chest and enters the abdomen through a hole in the diaphragm called the esophageal hiatus. The term hiatal hernia describes a condition where the upper part of the stomach that normally is located just below the diaphragm in the abdomen pushes or protrudes through the esophageal hiatus to rest within the chest cavity.
What are the signs and symptoms of a hiatal hernia?
By itself, a hiatal hernia causes no symptoms, and most are found incidentally when a person has a chest X-ray or abdominal X-rays (including upper GI series, and CT scans, where the patient swallows barium or another contrast material). It also is found incidentally during gastrointestinal endoscopy of the esophagus, stomach and duodenum (EGD).
The stomach is a mixing bowl that allows food and digestive juices to mix together to begin the digestive process. The stomach has a protective lining that prevents acid from eating away at the stomach muscle and causing inflammation.
Unfortunately, the esophagus does not have a similar protective lining. Instead, it relies on the lower esophageal sphincter (LES), a band of muscle located at the junction of the stomach and esophagus, and the muscle of the diaphragm surrounding the esophagus to act as a valve to prevent acid from refluxing from the stomach into the esophagus. Moreover, to the LES, the normal location of the stomach and esophageal junction within the abdominal cavity is important in keeping acid where it belongs. There is increased pressure within the abdominal cavity compared to the chest cavity, particularly during inspiration which would normally cause the acid and contents from the stomach to reflux back into the esophagus, but the combination of pressure exerted within the lowermost esophagus from the LES, and the muscle of the diaphragm create a zone of higher pressure that keeps stomach acid in the stomach.
In the situation of a sliding hiatal hernia, the GE junction moves above the diaphragm and into the chest, and the portion of the higher-pressure zone due to the diaphragm is lost. Acid is allowed to reflux back into the esophagus causing inflammation of the lining of the esophagus and the symptoms of gastroesophageal reflux disease (GERD).
These symptoms may include:
- heartburn, chest pain or burning,
- nausea, vomiting or retching (dry heaves)
- waterbrash, the rapid appearance of a large amount of saliva in the mouth that is stimulated by the refluxing acid
Symptoms usually are worse after meals, and may be made worse when lying flat. The symptoms may resolve with sitting up or walking.
In some patients, reflux into the lower esophagus sets off nervous reflexes that can cause a cough or even spasm of the small airways within the lungs (asthma). A few patients may reflux acid droplets into the back of their throat. This acid can be inhaled or aspirated into the lung causing coughing spasms, asthma, or repeated infections of the lung including pneumonia and bronchitis. This may occur in individuals of all ages, from infants to the elderly. Fortunately, this is very uncommon.
Most paraesophageal hiatal hernias have no symptoms of reflux because the GE junction remains below the diaphragm, but if the hernia is large, the way the stomach rotates into the chest, there is the possibility of volvulus of the stomach in which the stomach twists upon itself. Fortunately, paraesophageal hernias are relatively uncommon. Nevertheless, volvulus of the stomach is a surgical emergency and causes difficult, painful swallowing, chest pain, and vomiting.
What causes a hiatal hernia?
Normally, the space where the esophagus passes through the diaphragm is sealed by the phrenoesophageal membrane, (a thin membrane of tissue connecting the esophagus with the diaphragm) where the esophagus passes through the diaphragm. Thus, the chest cavity and abdominal cavity are separated from each other. Because the muscles of the esophagus tighten and the esophagus shortens with each swallow, essentially squeezing food into the stomach, this membrane needs to be elastic to allow the esophagus to move up and down. Normal physiology allows the gastroesophageal (GE) junction, where the esophagus and stomach meet, to move back and forth within the hiatus.. However, at rest the GE junction should be located below the diaphragm and in the abdominal cavity. It is important to remember that these distances are very short.
Over time, the phrenoesophageal membrane may weaken, and a part of the stomach may herniate through the membrane. It may remain above the diaphragm permanently or move back and forth across the diaphragm.
Hiatal hernias are common, and in the majority of cases the cause is unknown. They may be present at birth or develop later in life.
- Theoretically, decreased abdominal muscle tone and increased pressure within the abdominal cavity could lead to the development of a hiatal hernia. Thus, people who are obese and women who are pregnant may be at an increased risk for developing a hiatal hernia although this has not been demonstrated.
- Similarly, people who have repetitive vomiting or those who have constipation and strain to have a bowel movement, increase the intra-abdominal pressure when they strain, and this may weaken the phrenoesophageal membrane.
- The membrane also may weaken and lose its elasticity as a part of aging.
- Ascites, an abnormal collection of fluid in the abdominal cavity often seen in people with liver failure, also may be associated with the development of a hiatal hernia.
What are the types of hiatal hernias?
The most common type of hiatal hernia is a sliding hiatal hernia. This accounts for 95% of all hiatal hernias. Hiatal hernias are very common, occurring in up to 50% of the general population. With a sliding hernia, a portion of the stomach slides upward through the diaphragm and into the chest such that the junction of the esophagus and stomach (gastro- esophageal junction) lies in the chest. The hernia is present during inspiration when the diaphragm contracts and descends towards the abdominal cavity and when the esophagus shortens during swallowing, but at rest it is not present.
In paraesophageal hernia, the second type of hiatal hernia that accounts for only 5% of hiatal hernias, the gap in the the diaphragm through which the hernia occurs, phrenoesophageal membrane is larger, and a portion of the stomach herniates into the chest alongside the esophagus and stays there, but the junction between the stomach and the esophagus remains below the diaphragm.
In a combination of events, should the defect in the diaphragm become larger, the junction between the stomach and the esophagus can herniate through the diaphragm into the chest causing a hernia that is both paraesophageal and sliding.
How is hiatal hernia diagnosed?
Most often, a hiatal hernia is found incidentally with gastrointestinal X-rays, EGD, and sometimes CT scan, since by itself, it causes no symptoms. Only when there are associated symptoms of GERD will the patient usually seek medical care. With symptoms of GERD, it is likely that a hiatal hernia is present since most patients with GERD have hiatal hernias.
Often, the diagnosis is confirmed by a barium swallow or upper GI series, where a radiologist uses fluoroscopy to observe in real time as the swallowed barium outlines the esophagus, stomach and upper part of the small intestine. In addition to seeing the anatomy, the radiologist also can comment upon the movement of the muscles that work to propel the barium (and presumably) food through the esophagus into the stomach and beyond.
Endoscopy is a procedure performed under sedation by a gastroenterologist to look at the lining of the esophagus, stomach, and duodenum. A hiatal hernia may be diagnosed easily in this manner and more importantly, the physician may be able to see complications of GERD from the reflux of acid. Endoscopy is used to diagnose scarring with strictures (narrowing of the esophagus) and precancerous conditions like Barrett's esophagus. Biopsies or small tissue samples may be taken and examined under a microscope.
What is the treatment for hiatal hernia?
The treatment for hiatal hernia is really treatment for GERD and minimizing acid reflux. This includes decreasing acid secretion in the stomach, avoiding substances that are irritating to the stomach lining, and mechanical means to keep the remaining acid in the stomach where it belongs.
- Lifestyle changes may include elevating the head of the bed when sleeping to allow gravity to prevent acid from refluxing into the esophagus.
- Small frequent meals may help instead of eating two or three larger meals a day.
- Some foods that should be avoided include spicy, greasy foods, onions, tomatoes and citrus fruits, however, most individuals are generally aware of the foods that trigger heartburn symptoms and avoid them.
Hiatal hernia surgery
With the development of proton pump inhibitor medications, medical therapy has decreased the necessity of surgery for sliding hiatal hernias, and it is often only recommended for people who have failed aggressive drug treatment or who have developed complications of GERD like strictures, ulcers, and bleeding or those with repeated pneumonia form aspiration.
Patients with paraesophageal hernias often have no symptoms, and surgery is required only if the hernias become trapped in the chest and become stuck in the diaphragmatic hiatus or rotate to cause a volvulus. While this is more commonly seen in older people, paraesophageal hernias also may occur from birth as a congenital condition in neonates and infants.
Most often, the surgery is done as a minimally invasive procedure using a laparoscope. While there are different techniques, the results are similar and the best option is usually the one the surgeon feels most comfortable performing in a specific situation.
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Society of American Gastrointestinal and Endoscopic Surgeons. Guidelines for the Management of Hiatal Hernia.