Understanding the upper gut
The gut (gastrointestinal tract) is the tube that starts at the mouth, and ends at the anus.
The upper gut includes the oesophagus (gullet), stomach, and duodenum. Food passes down the oesophagus into the stomach. The stomach makes acid which is not essential, but helps to digest food. After being mixed in the stomach, food passes into the duodenum (the first part of the small intestine) to be digested.
The walls of the stomach contain muscle. At the junction of the stomach and the oesophagus there is a thickened area of muscle which is called a sphincter. The sphincter acts like a valve. When food comes down the oesophagus into the stomach, the sphincter relaxes. However, it closes at other times to stop food and acid in the stomach refluxing back into the oesophagus.
The diaphragm is a large flat muscle that separates the lungs from the abdomen. It helps us to breathe.
The oesophagus comes through a hole (hiatus) in the diaphragm just before it joins to the stomach. Normally, all of the stomach is below the diaphragm. The muscle fibres in the diaphragm around the lower oesophagus help the sphincter to keep the oesophagus closed to prevent reflux of acid and food.
What is a hernia and what is a hiatus hernia?
- A hernia is when part of an organ protrudes (pushes) through a muscular wall that holds it in place. There are different types of hernia. For example, an inguinal hernia is the most common type when part of the lower bowel protrudes through the muscle in the groin.
- A hiatus hernia is when part of the stomach protrudes through the diaphragm.
Types of hiatus hernia
- Sliding hiatus hernia is the most common type. In this situation, the sphincter at the bottom of the oesophagus and the top of the stomach protrudes through the hole (hiatus) in the diaphragm. The hernia may slide up and down, in and out of the lower chest. It is often quite small.
- Rolling hiatus hernia is less common. In this situation, part of the stomach protrudes up through the hole in the diaphragm next to the oesophagus.
What causes hiatus hernia and how common is it?
The exact number of people with a hiatus hernia is not known, as many people with a hiatus hernia do not have symptoms. However, they are thought to be common. Some studies suggest that up to a quarter of people being investigated for dyspepsia (indigestion) are discovered to have a hiatus hernia.
The cause of hiatus hernia is not clear. It is thought that most develop in people over the age of 50 years. It may be that the diaphragm weakens with age and allows part of the stomach to protrude through the hole in the diaphragm. Factors which increase the pressure in the abdomen, such as regular coughing, weight lifting, or obesity, may increase the risk of developing a hiatus hernia.
(There is a rare type of hiatus hernia which occurs in newborn babies, due to a congenital defect of the stomach or diaphragm. This is not dealt with further in this leaflet.)
What are the symptoms of hiatus hernia?
Often there are none
Many people with a hiatus hernia have no symptoms.
Acid reflux symptoms
The hernia itself does not cause symptoms. However, if you have a hiatus hernia, the factors that normally prevent stomach acid from refluxing into the oesophagus may not work so well. The sphincter may not work properly, and the normal pressure of the diaphragm on the oesophagus is lost. Therefore, you are more prone for acid in the stomach to reflux (regurgitate) into your oesophagus. The refluxed acid can cause inflammation of the lower part of the oesophagus which can cause one or more of the following symptoms:
- Heartburn: this is the main symptom. This is a burning feeling which rises from the upper abdomen or lower chest up towards the neck. (It is confusing as it has nothing to do with the heart!)
- Other common symptoms include: pain in the upper abdomen and chest, feeling sick, an acid taste in the mouth, bloating, belching, and a burning pain when you swallow hot drinks. Like heartburn, these symptoms tend to come and go, and tend to be worse after a meal.
- Some uncommon symptoms may occur. If any of these symptoms occur, it can make the diagnosis difficult, as these symptoms can mimic other conditions. For example:
- A persistent cough, particularly at night, sometimes occurs. This is due to the refluxed acid irritating the trachea (windpipe). Asthma symptoms of cough and wheeze can sometimes be due to acid reflux.
- Other mouth and throat symptoms sometimes occur such as gum problems, bad breath, sore throat, hoarseness, and a feeling of a lump in the throat.
- Severe chest pain develops in some cases (and may be mistaken for a heart attack).
Note: most people with acid reflux do not have a hiatus hernia. Also, most people with a hiatus hernia do not have symptoms of acid reflux. (If you have a hiatus hernia it does not necessarily mean that the sphincter between the oesophagus and stomach does not work so well. It is just that having a hiatus hernia makes you more prone to having a poorly functioning sphincter and more prone to developing acid reflux symptoms.)
However, people with a hiatus hernia who do get reflux, on average, tend to get more severe symptoms and problems associated with acid reflux. This may be because, with a hiatus hernia, any acid that gets into the oesophagus is more likely to remain in contact with the lining of the oesophagus for longer compared with people without a hiatus hernia.
See separate leaflet called ‘Acid Reflux and Oesophagitis’ for more details, including treatment.
How is a hiatus hernia diagnosed?
A hiatus hernia may be diagnosed if you have tests for symptoms of reflux. Endoscopy is the common test. This is where a thin, flexible telescope is passed down the oesophagus into the stomach. This allows a doctor or nurse to look inside. A hiatus hernia may be seen. A special X-ray test called a barium swallow is another more accurate way to confirm the presence of a hiatus hernia.
What is the treatment of hiatus hernia?
- If you have no symptoms, you do not need any treatment. The hiatus hernia itself causes no harm.
- If you have reflux symptoms, you should aim to lose weight if you are overweight. Also, avoid anything that causes pressure on your stomach, such as tight clothing and corsets.
- If you are a smoker you should aim to stop. If you drink a lot of alcohol, it also helps to cut down on alcohol.
- If changing your lifestyle does not help, you may need medication such as drugs which suppress acid production.
Rarely, a hiatus hernia causes severe symptoms of reflux which are not helped so well with medication. Therefore, an operation is occasionally advised. During this operation the stomach is put back into the correct position, and the weakened diaphragm around the lower oesophagus is tightened. Other procedures using endoscopy are also available.
What are the possible complications of a hiatus hernia?
Possible complications may occur if you have long-term reflux of acid into the oesophagus, which occurs in some cases. These include:
- Stricture. If you have severe and long-standing inflammation it can cause scarring and narrowing (a stricture) of the lower oesophagus. This is uncommon.
- Barrett’s oesophagus. In this condition the cells that line the lower oesophagus change. The changed cells are more prone than usual to becoming cancerous. (About 1 or 2 people in 100 with Barrett’s oesophagus develop cancer of the oesophagus.)
- Cancer. Your risk of developing cancer of the oesophagus is slightly increased compared with the normal risk if you have long-term acid reflux. This small increased risk is slightly higher still in people with reflux plus a hiatus hernia. This is because reflux problems, on average, tend to be more severe in people with a hiatus hernia compared to those without a hiatus hernia.
But note: it has to be stressed that most people with reflux or hiatus hernia do not develop any of these complications. They are uncommon. Tell your doctor if you have pain or difficulty when you swallow (food sticking), which may be the first symptom of a complication.
References and Disclaimer | Provide feedback
- Gordon C, Kang JY, Neild PJ, et al; The role of the hiatus hernia in gastro-oesophageal reflux disease. Aliment Pharmacol Ther. 2004 Oct 1;20(7):719-32. [abstract]
- Dyspepsia – proven gastro-oesophageal reflux disease, Clinical Knowledge Summaries (June 2008)
- Wu AH, Tseng CC, Bernstein L; Hiatal hernia, reflux symptoms, body size, and risk of esophageal and gastric adenocarcinoma. Cancer. 2003 Sep 1;98(5):940-8. [abstract]
- Dyspepsia: Managing dyspepsia in adults in primary care, NICE Clinical Guideline (2004)