A peptic ulcer is a break in the mucosal lining of the stomach or duodenum (the upper part of the small intestine), usually caused by an imbalance between factors promoting mucosal damage such as bacterial infection with Helicobacter pylori, gastric acid, pepsin and non-steroidal anti-inflammatory drugs and those promoting defence of the gastrointestinal tract.
The stomach produces hydrochloric acid and enzymes, including pepsin, that break down and digest food. A mucus layer coats the stomach and protects it from the acid. Prostaglandins, hormone-like substances involved in muscle contraction and the inflammatory response, also aid in protecting the lining. When these defences are not performing their job properly, acid and pepsin eat away at the lining, forming an open sore called an ulcer.
H. pylori decreases the stomach’s ability to produce mucus, making it more likely that acid will cause peptic ulcers. Although H. pylori infection is found in many people, it does not cause ulcers in all of them. However, of those who have peptic ulcers more than half have this infection.
Long-term use of non-steroidal anti-inflammatory agents (NSAIDs), such as aspirin, naproxen and ibuprofen can also cause peptic ulcers. Rarely, peptic ulcer is caused by the Zollinger-Ellison syndrome in which a tumour in the small intestine or pancreas produces large amounts of the hormone gastrin. Other rare causes include, certain medications such as potassium chloride and bisphosphonates and Crohn’s disease.
Smoking and heavy alcohol drinking can exacerbate peptic ulcers and slow healing. The risk of peptic ulcers and associated complications increase with age.