Hiatal hernia*

A hernia occurs when one part of the body protrudes through a gap or opening into another part. A hiatal hernia forms at the opening in your diaphragm where your food pipe (esophagus) joins your stomach. Part of the stomach pushes through this opening causing a hiatal hernia.

Most small hiatal hernias don't cause problems, and you may never know you have a hiatal hernia unless your doctor discovers it when checking for another condition. But a large hiatal hernia can allow food and acid to back up into your esophagus, leading to heartburn and chest pain. Self-care measures or medications can usually relieve these symptoms, although very large hiatal hernias sometimes need surgical repair.

Small hernias
Most small hiatal hernias cause no problems.

Large hernias
Larger hernias may cause the following signs and symptoms when stomach acids back up into your esophagus.

* Heartburn
* Belching
* Chest pain
* Nausea

These signs and symptoms tend to become worse when you lean forward, strain, lift heavy objects or lie down, and they can also worsen during pregnancy.

In rare cases
Sometimes, the part of your stomach that protrudes into your chest cavity may become twisted (strangulated) or have its blood supply cut off, leading to:

* Severe chest pain
* Difficulty swallowing (dysphagia)
* Obstruction of your esophagus

The exact cause of hiatal hernias isn't known. Your chest cavity and abdomen are separated by your diaphragm — a large dome-shaped muscle that's responsible for a major part of normal breathing. Your esophagus passes into your stomach through an opening in the diaphragm called the hiatus. Hiatal hernias occur when the muscle tissue surrounding this opening becomes weak, and the upper part of your stomach bulges up through the diaphragm into your chest cavity.

Pressure on the abdomen
Some people develop a hiatal hernia after an injury to the area. Others are born with an inherent weakness or an unusually large hiatal opening. But anything that puts intense pressure on your abdomen — including persistent or severe coughing or vomiting, pregnancy, straining while going to the bathroom, increased abdominal fluid or lifting heavy objects — can contribute to a hernia.