Synopsis
Distinguish histological gastritis from reactive gastric injury, identify infectious, autoimmune, chemical and vascular mechanisms, treat the cause rather than the endoscopic adjective, and recognise anaemia and premalignant mucosal change.
- Gastritis is a histological diagnosis of gastric mucosal inflammation, whereas gastropathy describes epithelial injury and regeneration with relatively little inflammation; dyspepsia alone proves neither.
- H. pylori is the commonest chronic infectious cause and can progress through atrophy and intestinal metaplasia toward gastric adenocarcinoma in a subset of patients.
- Autoimmune gastritis targets corpus and fundus parietal cells, producing achlorhydria, iron deficiency, later vitamin B12 deficiency and increased gastric neoplasia risk.
Key red flags
Coffee-ground vomiting, melaena or falling haemoglobin can arise from diffuse erosions, particularly with NSAIDs, alcohol, critical illness or portal hypertension, and requires formal bleeding-risk assessment.
Investigation priorities
Inspect mucosa, exclude ulcer or cancer and direct systematic biopsy.
Management branches
Endoscopy, anaemia, B12 deficiency or persistent upper-GI symptoms raises concern for mucosal disease.
- Review H. pylori, NSAIDs, aspirin, alcohol, bile-reflux surgery, portal hypertension, autoimmune history and immunosuppression rather than accepting a previous non-specific gastritis label.
- Use endoscopy when alarm or risk features justify it and obtain correctly sited biopsies so histology can distinguish active inflammation, reactive injury, atrophy, metaplasia and neoplasia.
Key medicines
Vitamin B12 replacement for autoimmune gastritisUse the NICE NG239 replacement route and locally agreed hydroxocobalamin or oral regimen for the clinical severity; autoimmune gastritis usually needs lifelong treatment with response-based follow-up.
Cause-specific acid suppressionChoose a licensed PPI and product-specific dose only when erosive injury, ulcer or continuing high-risk NSAID exposure provides a clear indication; define the review and step-down date.