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Vitamin B12 deficiency

Vitamin B12 deficiency is a topic covered in the Diagnosaurus.

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  • Dietary deficiency (seen in vegans)
  • Decreased intrinsic factor production: pernicious anemia, gastrectomy
  • Competition for B12 in gut: blind loop syndrome, fish tapeworm (rare)
  • Decreased ileal B12 absorption: surgical resection, Crohn's disease, metformin
  • Pancreatic insufficiency
  • Helicobacter pylori infection
  • Transcobalamin II deficiency (rare)

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Last updated: December 1, 2014


Zeiger, Roni F.. "Vitamin B12 Deficiency." Diagnosaurus, 4th ed., McGraw-Hill Education, 2014. Emergency Central, emergency.unboundmedicine.com/emergency/view/Diagnosaurus/114646/all/Vitamin_B12_deficiency.
Zeiger RF. Vitamin B12 deficiency. Diagnosaurus. 4th ed. McGraw-Hill Education; 2014. https://emergency.unboundmedicine.com/emergency/view/Diagnosaurus/114646/all/Vitamin_B12_deficiency. Accessed March 20, 2019.
Zeiger, R. F. (2014). Vitamin B12 deficiency. In Diagnosaurus. Available from https://emergency.unboundmedicine.com/emergency/view/Diagnosaurus/114646/all/Vitamin_B12_deficiency
Zeiger RF. Vitamin B12 Deficiency [Internet]. In: Diagnosaurus. McGraw-Hill Education; 2014. [cited 2019 March 20]. Available from: https://emergency.unboundmedicine.com/emergency/view/Diagnosaurus/114646/all/Vitamin_B12_deficiency.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Vitamin B12 deficiency ID - 114646 A1 - Zeiger,Roni F, Y1 - 2014/12/01/ BT - Diagnosaurus UR - https://emergency.unboundmedicine.com/emergency/view/Diagnosaurus/114646/all/Vitamin_B12_deficiency PB - McGraw-Hill Education ET - 4 DB - Emergency Central DP - Unbound Medicine ER -