Definition

Megaloblastic anemia is a blood disorder characterized by anemia, with red blood cells that are larger than normal. This condition usually results from a deficiency of folic acid or of vitamin B-12.

Alternative Names

Anemia - megaloblastic

Causes, incidence, and risk factors

Deficiencies of vitamin B-12 and folic acid are the most common causes of megaloblastic anemia. Other causes are leukemia, myelofibrosis, multiple myeloma, certain hereditary disorders, drugs that affect DNA synthesis such as chemotherapy drugs, alcohol abuse, and other causes. Risk factors relate to the causes. (See also pernicious anemia).

Symptoms

• Loss of appetite
• Diarrhea
• Tingling and numbness of hands and feet
• Pale skin color
• Tiredness
• Headaches
• Sore mouth and tongue
• Change in skin color

Signs and tests

Examination of the working of the nervous system may show abnormal reflexes, decreased position sense, and decreased vibration sense if the anemia is related to vitamin B-12 deficiency.

Tests include:

• Complete blood count (shows anemia with large red blood cells)
• Bone marrow examination
• Serum B-12
• Schilling test (may identify poor absorption as cause of vitamin B-12 deficiency)
• Serum folate

Treatment

The goal of treatment is to find out the cause of the anemia, and the treatment depends on the cause. Anemias related to vitamin deficiencies are discussed separately.

Expectations (prognosis)

The outcome is expected to be good with treatment.

Complications

Complications vary with the cause of the anemia.

Calling your health care provider

Call for an appointment with your health care provider if symptoms develop.

Prevention

Adequate intake of vitamin B-12 and folic acid is helpful.