The majority of problems in interpreting gastritis remain Helicobacter related but their nature has changed. Key points to remember in interpreting gastric biopsies are as follows:
a. Proton pump inhibitors (PPIs) or concurrent antibiotics decrease Helicobacter pylori bacterial load so that organisms may not be visible.
b. Diffuse antral predominant pan-gastritis with variable acute inflammation is characteristic of Helicobacter. When typical, the diagnosis can be made without necessarily identifying the bacteria in section although some may prefer serological confirmation. Confidently excluding the infection may not be possible without multiple biopsies from both the antrum and corpus so these should be sampled “routinely.”
c. PPIs facilitate proximal migration of the bacteria with accompanying inflammation and subsequent atrophy. PPI use may be diagnosable from the morphology of parietal cells in oxyntic biopsies.
d. PPIs facilitate the survival of non-H. pylori bacteria such that the presence of any gastric organisms (including cocci) is not synonymous with Helicobacter infection. Coccoid organisms rarely may be dead (nonpathogenic) Helicobacter but much more often are oral or duodenal contaminants.
e. Helicobacter is almost always accompanied by gastritis and should not be diagnosed in its absence.
f. Medications and other ingested substances can contribute to gastritis and gastropathy, interpreted endoscopically as gastritis because it appears red.
g. Unusual patterns of inflammation may point to primary diseases in the small intestine (lymphocytic colitis and celiac disease) or inflammatory bowel disease but can be completely masked by Helicobacter infection.
h. Akin to biopsies from other regions of the gastrointestinal tract, gastric biopsies should be examined systematically for the predominant histopathologic pattern with the intent of giving a clinically useful working diagnosis that impacts patient management. As all gastric inflammation is “nonspecific,” that term is best dropped from the reporting lexicon.