Definition - Causes, incidence, and risk factors - Symptoms - Signs and tests - Treatment - Expectations (prognosis) - Calling your health care provider .
Hypersegmented PMN (Close-up)
.jpg)
This image shows a large PMN with multiple
discretely-identifiable nuclear lobes, usually seen in megaloblastic anemias.
Normal PMN's have less than or equal to 5 lobes.
Definition
Megaloblastic
anemia is a blood disorder characterized by anemia, with red blood cells that
are larger than normal, usually resulting from a deficiency of folic acid
or of vitamin B-12.
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
agents (methotrexate), alcohol, 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
neurological signs may show abnormal reflexes, decreased position sense, and
decreased vibration sense if 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 objective of
treatment is to determine the cause of the anemia, and the treatment depends
upon 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 underlying cause.
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.