Hiatal Hernia

A hiatal hernia is by definition located in the thoracic cavity, also known as the chest cavity. More specifically, it is positioned in the inferior mediastinum, a division of the chest cavity that is between the lungs and includes many vital organs, such as the heart, great vessels, and esophagus. There are four types of hiatal hernia that push through the esophageal hiatus and into the thoracic cavity. 

Type I, also known as sliding hiatal hernia, occurs when the lower esophagus and stomach, including the gastroesophageal junction (GEJ), ascend through the hiatus. The GEJ is the point that connects the end of the esophagus to the stomach. Type 1 hiatal hernias are the most common type, making up more than 95% of hiatal hernia cases.

Type II, also called a pure (or classic) paraesophageal hernia, occurs when the upper part of the stomach (i.e., fundus) migrates into the thoracic cavity parallel to the esophagus, while the GEJ remains in the abdominal cavity.

Type III is a combination of a classic paraesophageal hernia and a sliding hernia. In type III, both the GEJ and a portion of the stomach have migrated into the thoracic cavity. This is sometimes referred to as a “mixed paraesophageal hernia.”

Finally, type IV occurs when the stomach, as well as other parts of the gastrointestinal (GI) tract, such as the small intestine or spleen, protrude into the chest.

Types II, III, and IV are considered subtypes of paraesophageal hernias, therefore this term is frequently used for all three types.

A hiatal hernia happens when the upper part of the stomach bulges through a weakness in the esophageal hiatus of the diaphragm. This weakness is occasionally due to birth defects that affect the prenatal development of the diaphragm and prevent it from closing as usual. 

Hiatal hernias can also be acquired. In such cases, they are more common in older adults. Muscle weakness, due to loss of flexibility and elasticity with age, is a major risk factor for developing a hiatal hernia. Other predisposing factors include trauma to the diaphragm and previous abdominal surgeries.

In addition, high abdominal pressure can increase the risk of developing a hiatal hernia. Circumstances that raise the pressure inside the abdominal cavity include obesity, pregnancy, chronic cough, and chronic constipation.

In order to diagnose a hiatal hernia, a thorough review of the individual’s medical history and a physical examination are typically necessary. Since hiatal hernias are not externally visible, diagnosis may require imaging or more invasive techniques. One imaging option involves a barium swallow, in which the individual drinks a liquid containing barium. The barium highlights the upper GI tract on an X-ray, providing valuable information about the size of the herniated stomach, as well as the location of the GEJ. Endoscopy of the upper GI tract involves the insertion of a flexible tube with a camera at the end into the individual’s mouth and down the throat to investigate the esophageal mucosa or wall, the mucosa of the stomach, and the duodenum. In some cases, computerized tomography (CT) scans may also be helpful in determining the location and type of hiatal hernia.

Treatment of hiatal hernias largely depends on the severity and the underlying cause. When confronted with a mild symptomatic hernia, the symptoms are usually a result of acid reflux, caused by GERD. Accordingly, medical treatment aims to reduce the symptoms of GERD by addressing stomach acid secretion. Some lifestyle modifications -- such as losing weight, elevating the head and chest during sleep, avoiding meals 2 to 3 hours before bedtime, and avoiding triggering foods (e.g., chocolate, alcohol, caffeine, and spices) -- may manage acid reflux. If such modifications prove ineffective, medications may be advised for symptom relief. Recommended medications may include proton pump inhibitors (PPI), like omeprazole, and antacids. However, treatment with medications provides only symptomatic relief, not a cure. 

In most other cases, treatment focuses on limiting the risk of obstruction, which is considered a medical emergency. Most individuals who develop symptoms from a paraesophageal hernia will experience little relief from acid-controlling medications, since the anatomical defect still exists. Therefore, surgery is often suggested to individuals with large hiatal hernias or those who experience intense symptoms, such as severe heartburns, chest pressure, or difficulty eating. 

The surgical procedure is not very invasive, and it consists of two parts. The first part involves returning the abdominal organs to the abdomen and repairing the hiatus in the diaphragm. The second part is a fundoplication. A fundoplication requires wrapping the fundus, the top part of the stomach, around the GEJ, forming a new, tighter barrier between the esophagus and the stomach.