Autoimmune Gastritis

Characterised by chronic inflammation of the gastric mucosa with atrophy, gland loss and metaplastic changes

Aetiology

  • Autoimmune

Pathophysiology

Autoimmune destruction of parietal cells

  • Decreased HCl production → increased gastrin → G cell hyperplasia → hypergastrinemia
  • Hypergastrinemia can lead to hyperplasia of enterochromaffin-like cells → carcinoid tumours

Production of autoantibodies against intrinsic factor

  • Results in B12 deficiency - ‘macrocytic’ anaemia
  • B12 is required for DNA synthesis

Clinical presentation

  • Haematemesis, melaena
  • Epigastric pain
  • Nausea and vomiting
  • Dyspepsia
  • Symptoms of anaemia/B12 deficiency

Investigations

Bloods

  • ↓ B12

Endoscopy + biopsy

  • Typically looks very atrophic due to persistent and progressive damage to the parietal cells

Management

  • B12 replacement therapy
  • Monitoring for gastric cancer