We speak of a hernia when an organ partially leaves the cavity that normally contains it, passing through a natural orifice.

If you have a hiatal hernia, it is the stomach which goes up in part through a small opening called the “esophageal hiatus”, located in the diaphragm, the respiratory muscle that separates the thoracic cavity from the abdomen.

The hiatus normally allows the esophagus (= tube that connects the mouth to the stomach) to pass through the diaphragm to bring food to the stomach. If it widens, this opening may allow part of the stomach or the entire stomach, or even other organs in the abdomen, to come up.

There are two main types of hiatus hernia:

• La sliding hernia or type I, which represents about 85 to 90% of cases.

  The upper part of the stomach, which is the junction between the esophagus and the stomach called “cardia”, goes up into the chest, causing burns associated with gastroesophageal reflux.

• La paraesophageal hernia or rolling or type II. The junction between the esophagus and the stomach remains in place below the diaphragm, but the larger part of the stomach “rolls” over and passes through the esophageal hiatus, forming a sort of pocket. This hernia usually does not cause any symptoms, but in some cases it can be serious.

There are also two other types of hiatus hernia, less common, which are in fact variants of paraesophageal hernia:

• Type III or mixed, when the sliding hernia and paraesophageal hernia coincide.
• Type IV, which corresponds to a hernia of the entire stomach sometimes accompanied by other viscera (intestine, spleen, colon, pancreas…).

Types II, III and IV together account for 10 to 15% of cases of hiatus hernia.

Who is affected?

According to studies, 20 to 60% of adults have a hiatus hernia at some point in their life. The frequency of hiatus hernias increases with age: they affect 10% of people under 40 and up to 70% of people over 60¹.

However, it is difficult to obtain an accurate prevalence because many hiatus hernias are asymptomatic (= do not cause symptoms) and therefore go undiagnosed.

Causes of the disease

The exact causes of hiatus hernia are not clearly identified.

In some cases, the hernia is congenital, that is, it is present from birth. It is then due to an anomaly of the hiatus which is too wide, or of the entire diaphragm which is poorly closed.

However, the vast majority of these hernias appear during life and are more common in older people. The elasticity and stiffness of the diaphragm seems to decrease with age, and the hiatus tends to widen, allowing the stomach to rise more easily. In addition, the structures that attach the cardia (= the gastroesophageal junction) to the diaphragm, and which keep the stomach in place, also deteriorate with age.

Some risk factors, such as obesity or pregnancy, can also be associated with hiatus hernia.

Course and possible complications

La sliding hiatus hernia mainly causes heartburn, but most often it is not serious.

La rolling hiatus hernia is often asymptomatic but tends to increase in size over time. It can be associated with life-threatening complications, such as:

• Breathing difficulties, if the hernia is large.
• Small continuous bleeding sometimes going as far as causing anemia from lack of iron.
• A torsion of the stomach (= gastric volvulus) which causes violent pain and sometimes necrosis (= death) of the part of the hernia in torsion, deprived of oxygen. The lining of the stomach or esophagus can also tear, causing digestive bleeding. We must then intervene urgently and operate on the patient, whose life may be in danger.