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Pernicious anemia

  • Alternative Names

    Macrocytic achylic anemia; Congenital pernicious anemia; Juvenile pernicious anemia; Vitamin B12 deficiency (malabsorption)


    People with mild anemia may have no symptoms or very mild symptoms. More typical symptoms of vitamin B12 deficiency anemia include:

    • Diarrhea or constipation
    • Fatigue, lack of energy, or light-headedness when standing up or with exertion
    • Loss of appetite
    • Pale skin
    • Problems concentrating
    • Shortness of breath, mostly during exercise
    • Swollen, red tongue or bleeding gums
    • Nerve damage caused by vitamin B12 deficiency that has been present for a longer time may cause:
      • Confusion or change in mental status (dementia) in severe or advanced cases
      • Depression
      • Loss of balance
      • Numbness and tingling of hands and feet

    Signs and tests

    Tests that may used to diagnose or monitor pernicious anemia include:

    • Bone marrow examination (only needed if diagnosis is unclear)
    • Complete blood count (CBC)
    • Measurement of serum holotranscobalamin II
    • Reticulocyte count
    • Schilling test
    • Serum LDH
    • Serum methylmalonic acid (MMA) level
    • Serum vitamin B12 level

    Pernicious anemia may also affect the results of the following tests:

    • Bilirubin
    • Cholesterol test
    • Gastrin
    • Leukocyte alkaline phosphatase
    • Peripheral smear
    • TIBC

    Vitamin B12 deficiency affects the appearance of cells that form on the outer surface of the body and line inner passageways (epithelial cells). An untreated woman may have a false positive Pap smear.