What is a hiatal hernia (definition)?

Photo illustration of a woman with esophageal pain.

Hiatal hernia can cause esophageal pain.

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).

Most often if symptoms occur, they are due to gastroesophageal reflux disease (GERD) where the digestive juice containing acid from the stomach moves up into the esophagus.

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:

  • heartburnchest pain or burning,
  • nausea, vomiting or retching (dry heaves)
  • burping
  • 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.