Gastritis

Overview – Gastritis

Gastritis refers to inflammation of the stomach lining and is a common cause of upper gastrointestinal symptoms. It may be acute or chronic and is frequently linked to Helicobacter pylori, NSAID use, and autoimmune mechanisms such as pernicious anaemia. If untreated, gastritis may progress to peptic ulcer disease (PUD), bleeding, or gastric cancer. Understanding its causes and appropriate investigation and treatment is crucial in both general and specialist practice.

Definition

Gastritis = Inflammation of the gastric mucosa.
It may present acutely or chronically and has a wide range of underlying causes and complications.

Protective vs Destructive Factors

Protective Factors

• Alkaline mucus layer → acts as a physical barrier
• Prostaglandins → stimulate mucin secretion from goblet cells

Destructive Factors

• Helicobacter pylori infection
• Gastric acid (pH ~2)
• Pepsin (secreted by chief cells; breaks down proteins)
• NSAIDs (e.g. aspirin, ibuprofen)
  • ↓Prostaglandins → ↓Mucosal defence
  • 15–20% of regular NSAID users develop gastric ulcers
• Stress (e.g. major burns → ↓plasma volume → mucosal ischemia)
• Gastrinoma / Zollinger-Ellison Syndrome

Aetiology & Pathogenesis

Acute Gastritis

• Alcohol (approx. 15% of cases)
• NSAIDs: inhibit COX → ↓Prostaglandins → hyperacidity → inflammation
• Severe physiological stress (e.g. burns) → mucosal ischaemia and necrosis

Chronic Gastritis

• 80% due to H. pylori infection
• Results in chronic mucosal inflammation → ↑risk of ulcer, gastric atrophy, metaplasia

Atrophic Gastritis

• Autoimmune (Pernicious anaemia)
  • Autoantibodies to parietal cells and intrinsic factor
  • → ↓Vitamin B12 absorption → megaloblastic anaemia

Clinical Features

• Abdominal discomfort
• Dyspepsia
• Bloating
• Nausea and vomiting
• +/- Haematemesis (if peptic ulceration present)
• +/- Anaemia (if B12 deficient or bleeding)

Investigations

• C13 Urea Breath Test – most specific for H. pylori
• Serology (IgG antibodies) – may indicate H. pylori exposure
• Faecal antigen test – detects H. pylori
• Endoscopy + gastric biopsy – assess inflammation, test for H. pylori, rule out malignancy

Management

Conservative

• Avoid aggravating factors: alcohol, NSAIDs

Medical

• Antacids – e.g. Mylanta
• PPIs – e.g. Omeprazole
• H2 antagonists – e.g. Ranitidine

Eradication Therapy (if H. pylori positive)

• Triple therapy:
  • Clarithromycin + Amoxicillin
  • +/- Metronidazole

Autoimmune (Pernicious Anaemia)

• Lifelong Vitamin B12 injections

Summary – Gastritis

Gastritis is inflammation of the stomach lining, most commonly caused by Helicobacter pylori, NSAIDs, and autoimmune factors such as pernicious anaemia. Presenting symptoms can include pain, dyspepsia, nausea, and anaemia. Key investigations include H. pylori testing and endoscopy. Management depends on the underlying cause and includes acid suppression, eradication of H. pylori, and B12 supplementation. For a broader clinical context, see our Gastrointestinal Overview page.