What Causes a Peptic Ulcer?

The stomach produces hydrochloric acid and an enzyme known as pepsin to break down food and to help protect the body from infection. The stomach and duodenum are protected from this acid by a lining of mucus (thick, sticky fluid). However, if this lining becomes damaged, then the delicate wall tissue may come into contact with the acid, becoming irritated and eventually ulcerated.

This may happen for a number of reasons; either because the stomach produces too much acid or there is insufficient mucus to protect the lining from damage. Ulcers may arise if the mucous membrane is damaged by an imbalance between the hydrochloric acid and pepsin. In the case of a gastric ulcer, too much acid may delay the passing of food through the pyloric sphincter to the duodenum. This would cause the acidic digestive juices to sit in the stomach for longer than normal, which could easily damage the lining. Duodenal ulcers may be formed when hydrochloric acid passes through the pyloric sphincter in unusually large quantities, often in the absence of food. The alkaline enzymes present in the duodenum are insufficient to neutralise this excess acid, and the lining is worn away. Occasionally, ulcers may form in the oesophagus if the acidic contents of the stomach run back into the lower part of the gullet. These oesophageal ulcers are usually a result weakness of the ring of muscle at the entrance to the gullet from the stomach, or pressure on the stomach, (for example, in late pregnancy).

Risk Factors

There are several factors that increase a person's risk of getting a peptic ulcer:

Helicobacter Pylori

It is thought that nearly all peptic ulcers are caused by bacteria known as Helicobacter pylori (H. pylori). It is thought that the proportion of Helicobacter pylori infections roughly matches age (that is, 20% of people have the infection at age 20, 40% at age 40, 60% at age 60 and so on). Although not everyone who carries the bacteria develops an ulcer, it is almost always present in those people who do have ulcers.

H. pylori inhabits the mucus lining of the stomach and duodenum, where it excretes an enzyme known as urease. This enzyme neutralises stomach acid, prompting the stomach to make more acid to counteract the enzyme's effect. This additional acid may then start to irritate the delicate lining of the stomach wall.

The bacteria is also thought to weaken the mucus lining so that it is less able to protect the stomach and duodenum walls, and may attach itself to the cells themselves, further weakening the stomach's defence system and causing inflammation in the affected area.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Medications such as aspirin, ibuprofen and naproxen reduce the stomach's ability to form a protective mucus layer. They may also affect blood flow to the stomach, which can affect body's ability to repair cells in this area.

Stress

Although stress probably does not cause ulcers, stressful situations can cause the stomach to produce more acid, thus worsening the symptoms if an ulcer is present.

Other Factors

Drinking alcohol and smoking reduce mucus production and irritate the stomach lining, both of which may contribute to the development of a peptic ulcer. It has also been suggested as peptic ulcers often run in families, genetic factors may be involved. Occasionally, a gastric ulcer may develop within a cancer in the lining of the stomach.