Blood Disorders

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Pernicious Anemia

What is pernicious anemia?

Pernicious anemia is low red blood cell counts due to low levels of vitamin B12. Vitamin B12 is important for many processes in the body including cell growth and red blood cells are particularly sensitive to low B12 levels. Vitamin B12 levels can be low for a number a reasons but in the case of pernicious anemia it is due to decreased absorption in the stomach due to the loss of a protein called intrinsic factor.

Diagnosis of pernicious anemia

People with pernicious anemia may not have any symptoms but will have a low hemocrit on a CBC with an increase average size of the red cells (MCV).  Other people may show symptoms of anemia or due to neurological symptoms including neuropathies or dementia. In addition to the low red blood cell counts and large cells, the peripheral smear may also show decreased numbers of white blood cells and abnormalities in the neutrophils. Blood tests for vitamin B12 are used for the diagnosis, but sometimes other biochemical blood tests are required. Folate deficiency may result in similar blood smear findings and should also be tested. Blood tests for intrinsic factor and antibodies to stomach cell proteins establishes the cause. Sometime endoscopy of the stomach is required.

Treatment of pernicious anemia

Treatment of pernicious anemia requires the replacement of vitamin B12 stores. Since patients with pernicious anemia have poor absorption, the vitamin is given via intramuscular shots.  In other patients, large doses of vitamin B12 tablets may be used.