Gastritis

Gastritis is a histopathological diagnosis. It is characterized endoscopically by erythema, erosions and haemorrhages. The histological pattern seen varies with aetiology:

• inflammation:
  • seen with chronic gastritis e.g. due to H. pylori.
  • characterised by infiltration of the lamina propria by mononucelar cells
  • the presence of polymorphs implies that there is concurrent acute gastritis
• atrophy - seen with autoimmune gastritis
• intestinal metaplasia:
  • seen with long-standing gastritis
  • a risk factor for malignant transformation
• 'reactive gastritis':
  • histological appearance that is seen with gastritis secondary to irritants

Previously gastritis was classified in an A / B / C classification where types A to C were:

• A - autoimmune gastritis - affects mainly stomach body
• B - bacterial gastritis - associated with H. pylori
• C - chemical gastritis - either drug-induced or e.g. bile-acid reflux

In this information source, the authors will describe gastritis in terms of the different aetiologies, e.g. autoimmune gastritis and not Type A gastritis.

Acute haemorrhagic gastritis will be discussed separately. This is because this may present as a gastroenterological emergency and so has to be managed acutely. Acute haemorrhagic gastritis may be due to aetiologies such as NSAIDs, alcohol, or Helicobacter pylori. This clinical entity is discussed in the appropriate section of the system.