Carton, Daly & Ramani: Clinical Pathology 
'Ask the Author' Forum
Figures from the bookCarton, Daly & Ramani: Clinical Pathology
March 2007: Gastritis
Q. You discuss 'gastritis' under the headings of Hp-associated, autoimmune, reactive and erosive/haemorrhagic gastritis. Other books I've looked at have talked about acute, chronic, active chronic gastritis - which I presume refers to the appearances down the microscope. However I'm unsure how the two classification schemes relate to each other eg. is Hp gastritis an acute, chronic or active chronic gastritis etc. Can you help?
A. As you've discovered, terminology and classification in gastritis is extremely confusing. Acute gastritis, chronic gastritis, and active gastritis are microscopic terms used by histopathologists to refer to the nature of an inflammatory infiltrate in the gastric mucosa. Acute refers to a neutrophil rich infiltrate, whilst chronic refers to a lymphocyte and plasma cell rich infiltrate. "Active" refers to a mixture of the two but is essentially a subtype of chronic gastritis. Whilst the nature of the infiltrate may provide a clue to the underlying cause of the inflammation, the terms in themselves carry no diagnostic connotation.
Erosive/haemorrhagic gastritis, HP-associated gastritis, autoimmune gastritis, and reactive gastritis are all recognised disease entities with different causes and treatment. Erosive/haemorrhagic gastritis (usually caused by gastric irritants or impaired gastric blood flow) is characterised histologically by an acute gastritis rich in neutrophils, together with multiple breaches in the gastric epithelium (known as "erosions" or "ulcers" according to how deep they go). HP-associated gastritis and autoimmune gastritis are both characterised histologically by a chronic (or active) gastritis which, in long standing cases, may also cause atrophy and/or intestinal metaplasia.
Reactive gastritis is a change in the gastric mucosa which usually occurs in the antrum due to bile refluxing into the stomach. Areas of reactive gastritis in the stomach appear red and thus appear as if "inflamed" at endoscopy. Microsopically, reactive gastritis has a characteristic appearance but does not actually show any inflammation, so strictly speaking it is not a gastritis at all! Many authorities have attempted to rename reactive gastritis with the more accurate term "reactive gastropathy" to reflect the lack of inflammation, but this has not met with much success and hence this condition still tends to be classified with the other genuine types of gastritis.
We hope you find these comments helpful.
James Carton and Richard Daly
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