MedSchool: Ace Your OSCEsThe Medical Company
GET - On the App Store
Red Cell Disorders

B12 Deficiency Anaemia



Vitamin B12, also known as cobalamin, is an important cofactor in the homocysteine metabolism, haemoglobin synthesis and myelination.


  • Causes of B12 Deficiency

  • Atrophic gastritis - pernicious anaemia, H pylori infection
  • Malabsorption - coeliac disease, tropical sprue, Crohn's disease, alcohol abuse
  • Surgical resection - gastrectomy, gastric bypass, resection of terminal ileum
  • Pancreatic insufficiency - chronic pancreatitis
  • Inherited disorders - Imerslund-Gräsbeck syndrome
Dietary deficiency is rare as a cause of B12 deficiency.


  • Manifestations of B12 Deficiency Anaemia

  • Megaloblastic anaemia
  • Atrophic glossitis
  • Peripheral neuropathy
  • Dementia


  • Investigations

  • Reduced Vitamin B12 level
  • Macrocytic, hyperchromic anaemia
  • Hypersegmented neutrophils
Next Page
Want more info like this?
  • Your electronic clinical medicine handbook
  • Guides to help pass your exams
  • Tools every medical student needs
  • Quick diagrams to have the answers, fast
  • Quizzes to test your knowledge
Sign Up Now

Snapshot: Initialising...