Overview of Gastritis

ByNimish Vakil, MD, University of Wisconsin School of Medicine and Public Health
Reviewed/Revised Mar 2023
View Patient Education

    Gastritis is inflammation of the gastric mucosa caused by any of several conditions, including infection (Helicobacter pylori), drugs (nonsteroidal anti-inflammatory drugs, alcohol), stress, and autoimmune phenomena (atrophic gastritis). Many cases are asymptomatic, but dyspepsia and gastrointestinal bleeding sometimes occur. Diagnosis is by endoscopy. Treatment is directed at the cause but often includes acid suppression and, for H. pylori infection, antibiotics.

    Gastritis can be classified in several ways:

    • By severity of mucosal injury, as erosive gastritis or nonerosive gastritis

    • 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 (see also Overview of Acid Secretion). Additionally, the term is often loosely applied to nonspecific (and often undiagnosed) abdominal discomfort and gastroenteritis.

    Acute gastritis is characterized by polymorphonuclear leukocyte infiltration of the mucosa of the antrum and body.

    Acute Gastritis
    Hide Details
    This image show acute gastritis caused by Helicobacter pylori infection.
    Image provided by David M. Martin, MD.

    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).

    Chronic Gastritis
    Hide Details
    Notice the atrophic appearance, which is consistent with chronic gastritis.
    Image provided by David M. Martin, MD.
    quizzes_lightbulb_red
    Test your KnowledgeTake a Quiz!
    Download the free Merck Manual App iOS ANDROID
    Download the free Merck Manual App iOS ANDROID
    Download the free Merck Manual App iOS ANDROID