Gastritis and gastropathy

Many etiological agents can induce gastritis, but the most common cause is infection by Helicobacter pylori , a bacterium that resides in the mucus gel layer overlaying the gastric mucosa. This chapter discusses some pathogens and exogenous agents that induce gastric inflammation and gastropathy. The most widely used method for classification of gastritis and reporting of nonneoplastic gastric biopsies in the research setting is the updated Sydney system, which classifies chronic gastritis based on topography, morphology, and etiology. Three patterns of chronic nonspecific gastritis are recognized: diffuse antral gastritis (nonatrophic gastritis in the Sydney system), multifocal atrophic gastritis, and diffuse corporal atrophic gastritis. Risk factors for H. pylori acquisition include lower socioeconomic status and household crowding, and colonization rates reflect country of origin and ethnicity. Autoimmune gastritis is a chronic atrophic gastritis restricted to the body of the stomach and associated with circulating antiparietal cell and anti-intrinsic factor antibodies with resulting intrinsic factor deficiency.