Another cause is putting too much pressure (repeatedly) on the muscles around your stomach. This can happen when:
- straining during bowel movements
- lifting heavy objects
Some people are also born with an abnormally large hiatus. This makes it easier for the stomach to move through it.
Factors that can increase your risk of a hiatal hernia include:
There are generally two types of hiatal hernia: sliding hiatal hernias and fixed, or paraesophageal, hernias.
Sliding hiatal hernia
This is the more common type of hiatal hernia. It occurs when your stomach and esophagus slide into and out of your chest through the hiatus. Sliding hernias tend to be small. They usually don’t cause any symptoms. They may not require treatment.
Fixed hiatal hernia
This type of hernia isn’t as common. It’s also known as a paraesophageal hernia.
In a fixed hernia, part of your stomach pushes through your diaphragm and stays there. Most cases are not serious. However, there is a risk that blood flow to your stomach could become blocked. If that happens, it could cause serious damage and is considered a medical emergency
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, so that the chest cavity and abdominal cavity are separated from each other. Because the esophagus shortens and lengthens 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 from just below to just above the diaphragm. 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 and remain above the diaphragm permanently.
- Decreased abdominal muscle tone and increased pressure within the abdominal cavity may lead to the development of a hiatal hernia. Thus, peopole who are obese and women who are pregnant are at an increased risk for developing a hiatal hernia.
- 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 is associated with the development of a hiatal hernia.
Symptoms of a hiatal hernia- 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) located at the GE junction 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. In addition to the LES, the normal location of the GE 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, and the combination of pressure exerted within the lowermost esophagus from the LES, the diaphragm and the abdominal cavity creates a zone of higher pressure that keeps stomach acid in place.
In the situation of a sliding hiatal hernia, the GE junction moves above the diaphragm and into the chest, and the higher pressure zone is lost. Acid is allowed to reflux back into the esophagus causing inflammation of the lining of the esophagus and the symptoms of GERD.
These symptoms may include the following:
- 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. These symptoms may be made worse when lying flat and may resolve with sitting up or walking.
In some patients, reflux into the lower esophagus sets off nervous reflexes that can cause acough 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 includingpneumonia and bronchitis. This may occur in individuals of all ages, from infants to the elderly.
Most paraesophageal hiatal hernias have no symptoms of reflux because the GE junction remains below the diaphragm, but because of the way the stomach has rotated into the chest, there is the possibility of a gastric volvulus, where the stomach twists upon itself. Fortunately, paraesophageal hernias are relatively uncommon. However, volvulus is a surgical emergency and causes difficult, painful swallowing, chest pain, and vomiting.
It’s rare for even fixed hiatal hernias to cause symptoms. If you do experience any symptoms, they’re usually caused by stomach acid, bile, or air entering your esophagus. Common symptoms include:
- heartburn that gets worse when you lean over or lie down
- chest pain or epigastric pain
- trouble swallowing
An obstruction or a strangulated hernia may block blood flow to your stomach. This is considered a medical emergency. Call your doctor right away if:
- you feel nauseated
- you’ve been vomiting
- you can’t pass gas or empty your bowels
Don’t assume that a hiatal hernia is causing your chest pain or discomfort. It could also be a sign of heart problems or peptic ulcers. It’s important to see your doctor. Only testing can find out what is causing your symptoms.
What is the connection between GERD and hiatal hernias?
Gastroesophageal reflux disease (GERD) occurs when the food, liquids, and acid in your stomach end up in your esophagus. This can lead to heartburn or nausea after meals. It’s common for people with a hiatal hernia to have GERD. However, that doesn’t mean either condition always causes the other. You can have a hiatal hernia without GERD or GERD without a hernia.
Testing for and diagnosing hiatal hernias
Several tests can diagnose a hiatal hernia.
Your doctor may have you drink a liquid with barium in it before taking an X-ray. This X-ray provides a clear silhouette of your upper digestive tract. The image allows your doctor to see the location of your stomach. If it’s protruding through your diaphragm, you have a hiatal hernia.
Your doctor may slide a thin tube in your throat and pass it down to your esophagus and stomach. Your doctor will then be able to see if your stomach is pushing through your diaphragm. Any strangulation or obstruction will also be visible.