Causes of Peptic Ulcers
Any cause of inflammation of the stomach or duodenal lining can lead to peptic ulcer formation. This also applies to other parts of the alimentary tract. However, the two main mechanisms by which most peptic ulcers occur include :
- Natural protective mechanisms that protect the lining of the stomach and duodenum are compromised. In the stomach, mucus secreted by the stomach lining protects it, while in the duodenum, bicarbonate ions and water from the pancreatic ducts neutralize the stomach acid.
- Increased gastric acid volume and acidity (lower pH). This is usually controlled by digestive hormones and nervous regulation as explained under Stomach Nerves.
While the stomach and duodenum have protective mechanisms to counteract the effects of hydrochloric acid and pepsin, the esophagus and other sections of the small intestine are unable to do so. Despite this, the stomach and duodenum are most prone to peptic ulcers.
A peptic ulcer can be acute or chronic but even if an acute ulcer heals, there is a risk of it recurring. Peptic ulcers are the most common complication of chronic gastritis, irrespective of the cause. The two most common causes of peptic ulcers are due to H.pylori infection and NSAIDs (non-steroidal anti-inflammatory drugs). Both cause an ulcer by one or both of the mechanisms explained above. However, not every person who uses NSAIDs or has an H.pylori infection will suffer with peptic ulcers.
H.pylori Peptic Ulcer
Helicobacter pylori (H.pylori) is a spiral shaped Gram-negative bacterium, which has multiple flagella (tail-like protrusions), that allow it to move and burrow into the lining of the gut. It is predominantly found in the stomach and duodenum and infection can occur in early childhood although a person may remain asymptomatic for years or even decades. It can also be spread through contaminated water and food or oral contact between people, like in kissing.
H.pylori can withstand the stomach acid by secreting the enzyme urease. Once it attaches to the epithelial lining of the stomach, it can cause peptic ulcers by :
- deactivating the stomach’s protective mechanism against the gastric secretion. This causes the stomach lining to be irritated by gastric acid and even digested by pepsin.
- stimulating the release of gastrin, the digestive hormone that increases gastric acid secretion. The excess gastric acid will empty into the duodenum where it damages the lining and causes duodenal ulcers.
H.pylori infection appears to be the most common cause of peptic ulcer disease. However, in many cases, other contributing factors such as excess alcohol consumption and cigarette smoking tend to be present as well.
NSAIDs Peptic Ulcer
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used these days for a range of inflammatory conditions where pain is a prominent symptom. It reduces inflammation by disrupting prostaglandin synthesis thereby disturbing the biochemical pathway of inflammation. However, this effect on prostaglandin synthesis also impairs the stomach’s natural defense mechanism against hydrochloric acid and pepsin . The mucus produced by the epithelial lining is diminished and gastric acid can therefore injure the stomach lining. Most cases of peptic ulcers due to the use of NSAIDs occurs in the stomach. While not every person using an NSAID will develop a peptic ulcer, it is more common in people who :
- are over the age of 60 years
- have a history of peptic ulcer disease
- use NSAIDs for a prolonged period of time
Other Causes of Peptic Ulcers
H.pylori infection and NSAIDs account for some 80% of all cases of peptic ulcer disease. However a number of other causative and contributing factors may also be responsible. This includes :
- Cigarette smoking
- Excess alcohol consumption
- Ingestion of causatic agents
- Debilitated or severely ill patients (stress gastritis)
- Zollinger-Ellison syndrome (hypersecretion of gastric acid)
- Cancer treatment (chemotherapy or radiation therapy)
Basically any factor that can cause gastritis, can lead to peptic ulcer disease. This is discussed further under Types of Gastritis. Stress and spicy foods generally do not cause peptic ulcers but are known aggravating factors that affect most ulcer sufferers. These factors are important considerations in the management of peptic ulcer disease.