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Alternative Names Return to topMacrocytic anemia
Definition Return to top
B12 deficiency anemia is a low red blood cell count due to a lack of vitamin B12.
Causes Return to top
Vitamin B12 is essential for normal nervous system function and blood cell production. The main sources of vitamin B12 include meat, eggs, and dairy products. For vitamin B12 to be sufficiently absorbed by the body, it must bind to intrinsic factor, a protein released by cells in the stomach. The combination of vitamin B12 bound to intrinsic factor is absorbed in the final part of the small intestine.
Causes of vitamin B12 deficiency include:
The risk factors are related to the causes.
Symptoms Return to top
Exams and Tests Return to top
A physical exam may show problems with reflexes or positive Babinski reflex.
The following tests may be done:
Treatment Return to top
Treatment depends on the specific cause of B12 deficiency anemia.
Pernicious anemia requires lifelong vitamin B12 injections. People with anemia due to a lack of dietary vitamin B12 may be told to take vitamin supplements and follow a more balanced diet. Treatment may start with vitamin B12 injections.
Anemia caused by malabsorption is treated with vitamin B12 injections until the condition improves.
Outlook (Prognosis) Return to top
Treatment for this form of anemia is usually effective.
Possible Complications Return to top
When to Contact a Medical Professional Return to top
Call your health care provider if you have any of the symptoms of anemia.
Prevention Return to top
Anemia caused by a lack of vitamin B12 can be prevented by following a well-balanced diet. B12 injections can prevent anemia after surgeries known to cause vitamin B12 deficiency. Early diagnosis and prompt treatment can limit the severity and complications of this anemia.
References Return to top
Antony AC. Megaloblastic anemias. Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 170.Update Date: 11/23/2008 Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.