Causes and Risk Factors of Hiatal Hernia

A hiatal hernia is caused by weakness of the muscles of the diaphragm. Most of the time, it is not clear why a hiatal hernia develops, although there are some risk factors. Conditions that cause pressure on the muscles of the diaphragm or conditions that weaken the muscle can increase your chances of developing a hiatal hernia.

Weakness of the diaphragmatic muscles allows the stomach to enter the area above the diaphragm instead of remaining securely below the diaphragm, where it belongs.

The diaphragm is a powerful muscle that separates the upper chest cavity from the abdominal compartments. It has an opening through which the esophagus connects with the stomach, as the esophagus is normally above the diaphragm, while the stomach is normally below the diaphragm. The diaphragm also helps open the space in the chest cavity when you take a deep breath in, so it is normally well anchored in the body.

Causes of Diaphragmatic Muscle Weakness

• Aging: Overall, the chances of having a hiatal hernia increase as you get older. The diaphragmatic muscles naturally become weaker and more flexible with advancing age, and, as you get older, you are more likely to experience the risk factors for hiatal hernia. Exceptions include congenital (from birth) and hereditary hiatal hernia, which develops at an early age.
• Trauma: Traumatic injury can contribute to pressure on the diaphragm, causing expansion of the opening in muscle.
• Surgery: Abdominal surgery may increase your chances of developing a hiatal hernia.
• Congenital: Babies and young children can have a hiatal hernia from birth. This can be repaired surgically.

Displacement of the stomach because of weakened diaphragm muscles can cause various types of hernia.

Sliding Hernia

A sliding hernia is a condition in which your stomach can periodically slide above the diaphragm due to a wide opening in the diaphragm or weakness of the diaphragmatic muscle. If you have a sliding hernia, your stomach is not anchored in place, but the anatomical relationship between your stomach and your esophagus, which lies right above it, is maintained as a normal anatomical relationship.

The hernia worsens during times of abdominal pressure, with the stomach literally sliding into the space above the diaphragm. The stomach can then return to its original position when there is no excessive abdominal pressure.

Paraesophageal Hernia

This type of hernia is caused when the stomach goes through an enlarged opening in the diaphragm. In this type of hiatal hernia, the stomach sits next to the esophagus. It does not move around or slide, but remains in the abnormal position next to the esophagus, where it may actually become squeezed or strangled by the diaphragm.

In general, a hiatal hernia is not believed to be genetic, but the most common hereditary conditions that may be associated with a hiatal hernia is Ehlers Danlos syndrome. This is connective tissue disease that has a variety of clinical manifestations, including easy bruising and overly flexible joints. Hiatal hernia may be present as well.

This is an autosomal recessive condition, which means that you would have to inherit the gene from both of your parents in order to develop the disease. Because it is recessive, if each of your parents only has one gene for Ehlers Danlos Syndrome, then they would not have the disease, and you could be the first person in your family to have clinical manifestations of the syndrome.

There are a few lifestyle risk factors that increase your chances of having a hiatal hernia. For many of these risk factors, the link to hiatal hernia is well established, but the cause is unclear.

• Obesity: Obesity is one of the biggest risk factors for hiatal hernia. This may be due to increased pressure on the diaphragm due to heavy weight.
• Heavily lifting: It is believed that heavy lifting puts stress on the diaphragmatic muscle, increasing the chances of an enlarged hole that allows the stomach to protrude above the diaphragm.
• Coughing: The abdominal pressure caused by coughing can allow or cause the stomach to squeeze through the diaphragm.
• Straining: Straining may increase the chances of having a hiatal hernia due to excess pressure on the diaphragm. This includes straining for a bowel movement. 
• Pregnancy: The abdominal pressure and hormonal changes of pregnancy can increase the chances of a hiatal hernia.
• Smoking: Smoking weakens the muscles of the diaphragm, allowing the stomach to protrude above the diaphragm.