What are the causes of pyloric canal ulcer?

1. Besides frequent exposure to high concentrations of gastric acid, the gastroduodenal mucosa is also invaded by harmful substances such as pepsin, microorganisms, bile salts, ethanol, and medications. However, under normal circumstances, the gastroduodenal mucosa can resist the damage caused by these invasive factors and maintain the integrity of the mucosa.

2. This is because the gastroduodenal mucosa has a series of defensive and repair mechanisms, including the mucus/bicarbonate barrier, mucosal barrier, mucosal blood flow, cell renewal, prostaglandins, and epidermal growth factor.

3. The occurrence of pyloric canal ulcer is the result of a loss of balance between the invasive factors and the mucosa's own defensive and repair factors for the gastroduodenal mucosa. This balance may be disrupted by an increase in invasive factors, a decrease in defensive and repair factors, or both. The pathogenesis of gastric ulcer (GU) and duodenal ulcer (DU) differs. The former is mainly due to weakened defensive and repair factors, while the latter is mainly due to enhanced invasive factors. Peptic ulcer is a disease caused by multiple factors, meaning that the etiology and pathogenesis may vary among patients, but the clinical manifestations are similar.