Normally, the esophagus passes through a hole in the diaphragm to connect to the stomach, which sits below the diaphragm. The diaphragm is a muscle that separates the organs in the chest from the organs in the abdomen.
A hiatal hernia is when a part of the stomach moves up into the chest area. Hiatal hernias are classified into sliding and/or paraesophageal hernias. A sliding hernia is when the top of the stomach and the lower part of the esophagus move up into the space above the diaphragm. This is the most common type of hiatal hernia. A paraesophageal hernia is when the top of the stomach alone squeezes up into the space above the diaphragm. This is not very common.
It is not always clear what causes a hiatal hernia. The distal end of the esophagus is anchored to the diaphragm by an elastic ligament called the phrenoesophageal ligament. With every swallow, the esophagus shortens to above the diaphragm, stretching this elastic ligament. After the swallow is completed, the elastic recoil of the ligament then pulls the distal end of the esophagus back to its normal position at the level of the diaphragm. For a sliding hiatal hernia, it is thought that with wear and tear of this elastic ligament from repetitive swallowing or other stressors (e.g. vomiting, gastroesophageal reflux), the ligament can no longer hold the distal esophagus in place as well and the stomach herniates upwards through the diaphragmatic opening.
For a paraesophageal hiatal hernia, it is thought that there is an abnormal laxity of the ligaments that normally hold the stomach in place, although it is not clear whether this laxity is a cause or an effect of the hernia. Hiatal hernias may also be congenital or develop after esophageal or gastric surgeries.
Hiatal hernias are common findings that are often incidentally found. Most small sliding hiatal hernias are asymptomatic. Patients with large sliding hiatal hernias may have symptoms of gastroesophageal reflux disease (GERD), including heartburn, regurgitation, and dysphagia.
Many patients with paraesophageal hernias either have no symptoms or have vague, intermittent symptoms. The most common symptoms for paraesophageal hernias are epigastric or substernal pain, postprandial fullness, nausea, or retching. In some patients, the volume of a stomach full of fluid or food can cause shortness of breath. When paraesophageal hernias get large, the stomach can twist and cause obstruction.
For both types of hiatal hernias, gastric ulcerations called Cameron lesions can form, causing anemia or gastrointestinal bleeding.
Hiatal hernias are often incidentally diagnosed on radiographic imaging, upper endoscopy, or esophageal manometry. These studies are usually not being done to specifically diagnose a hiatal hernia, but rather to exclude other diagnoses or as part of other workup.
Asymptomatic hiatal hernias do not need treatment.
Treatment for symptomatic sliding hiatal hernias usually consists of management of GERD. If symptoms are refractory or not amenable to medical treatment, then surgery can be considered. During surgery, the surgeon pulls the stomach back down into the abdomen and tightens the opening in the diaphragm to prevent the stomach from sliding back up above the diaphragm. A fundoplication is then done where the upper part of the stomach is wrapped around the lower portion of the esophagus to prevent reflux.
Symptomatic paraesophageal hernias require surgery. Emergent surgery is required for patients with complications secondary to a paraesophageal hernia (e.g. gastric volvulus, uncontrolled bleeding, obstruction, strangulation, perforation, and respiratory compromise).