The normal stomach and duodenum are able to resist autodigestion by acid-pepsin. Regardless of location and etiology, chronic peptic ulcers appear to be similar pathologically. Despite great progress in our understanding of risk factors for peptic ulcers, the etiology of most peptic ulcers is still unclear. Especially intriguing is the question of why an ulcer is such a focal lesion.
Peptic ulcers require the presence of acid-pepsin.
The pathogenesis of H. pylori -related peptic ulcers is not yet well understood. No theory explains why duodenal ulcers develop in some infected individuals, gastric ulcers develop in others, and most experience no ulcers at all. H. pylori organisms were not seen in the duodenum of gastric ulcer patients or control subjects. Furthermore, cure of H. pylori infection with antimicrobial therapy markedly reduces recurrences of gastric and duodenal ulcers. Experimental studies have been corroborated by numerous case-control studies and autopsy studies.