Gastritis can be classified in several ways:
By severity of mucosal injury, as erosive gastritis Erosive Gastritis Erosive gastritis is gastric mucosal erosion caused by damage to mucosal defenses. It is typically acute, manifesting with bleeding, but may be subacute or chronic with few or no symptoms. Diagnosis... read more or nonerosive gastritis Nonerosive Gastritis Nonerosive gastritis refers to a variety of histologic abnormalities that are mainly the result of Helicobacter pylori infection. Most patients are asymptomatic. Diagnosis is by endoscopy. Treatment... read more
By the site of involvement (ie, cardia, body, antrum)
Histologically as acute or chronic (based on the inflammatory cell type)
No classification scheme matches perfectly with the pathophysiology; a large degree of overlap exists. Some forms of gastritis involve acid peptic disease and H. pylori disease Helicobacter pylori Infection Helicobacter pylori is a common gastric pathogen that causes gastritis, peptic ulcer disease, gastric adenocarcinoma, and low-grade gastric lymphoma. Infection may be asymptomatic or result... read more (see also Overview of Acid Secretion Overview of Acid Secretion Acid is secreted by parietal cells in the proximal two thirds (body) of the stomach. Gastric acid aids digestion by creating the optimal pH for pepsin and gastric lipase and by stimulating pancreatic... read more ). Additionally, the term is often loosely applied to nonspecific (and often undiagnosed) abdominal discomfort and gastroenteritis Gastroenteritis Gastroenteritis is inflammation of the lining of the stomach and small and large intestines. Most cases are infectious, although gastroenteritis may occur after ingestion of drugs and chemical... read more .
Acute gastritis is characterized by polymorphonuclear leukocyte infiltration of the mucosa of the antrum and body.
Chronic gastritis implies some degree of atrophy (with loss of function of the mucosa) or metaplasia. It predominantly involves the antrum (with subsequent loss of G cells and decreased gastrin secretion) or the corpus (with loss of oxyntic glands, leading to reduced acid, pepsin, and intrinsic factor).