The intriguing relationship of Helicobacter pylori infection and acid secretion in peptic ulcer disease and gastric cancer.

Helicobacter pylori infection induces chronic inflammation of the gastric mucosa and thus profoundly affects gastric physiology. In the acute phase of infection, gastric acid secretion is transiently impaired. The morphological damage of the gastric mucosa, changes in gastric hormone release, and disruption of neural pathways all contribute to influence gastric acid secretion in a distinct manner. Changes in gastric acid secretion, whether impaired or increased, are intimately related with the topographic phenotypes of gastritis and the presence of atrophy or absence of corpus atrophy. The interplay of gastritis phenotype and acid secretion are key determinants in disease outcomes. Corpus-predominant gastritis and corpus atrophy are accompanied by hypochlorhydria and carry the highest risk for gastric cancer, whereas antrum-predominant gastritis with little involvement of the corpus-fundic mucosa is associated with hyperchlorhydria and predisposes to duodenal ulcer disease.