Hello - thanks for asking your question.
Although I am an internal medicine physician, please see your primary
care physician for specific questions regarding any individual cases
please do not use Google Answers as a substitute for medical advice.
I will be happy to answer factual medical questions.
What you are describing is anemia. This is defined as a reduction
below normal in the number of red blood cells (RBCs) in the
circulation. There are many, many causes for this, and I will briefly
describe the major causes as well as suggest a recommended course of
Loss of RBC cells is generally from one of three mechanisms:
decreased RBC production, increased RBC destruction, and RBC loss.
1) Decreased RBC production
Causes of decreased RBC production include the following:
- Lack of nutrients, such as iron, B12, or folate
- Primary involvement of the bone marrow, such as occurs in aplastic
anemia, pure RBC aplasia, myelodysplasia, or infiltration with tumor
- Suppression of bone marrow function secondary to drugs, cancer
chemotherapy, or irradiation.
- Low levels of hormones which normally stimulate RBC production, such
as EPO in chronic renal failure, thyroid hormone, and androgens.
2) Increased RBC destruction
Causes include various types of hemolytic anemias (i.e. when the bone
marrow is not able to produce enough red blood cells to offset the
loss of red blood cells). Diseases include the following:
- Inherited hemolytic anemias (eg, hereditary spherocytosis, sickle
cell disease, thalassemia major)
- Acquired hemolytic anemias (eg, Coombs'-positive autoimmune
hemolytic anemia, thrombotic thrombocytopenic purpura-hemolytic uremic
3) RBC loss
Blood loss is the most common cause of anemia. Causes of this
includes the following:
- Obvious bleeding, such as traumatic blood loss, melena (symptomatic
of an upper GI bleed), hematemesis (blood in the vomit), or
menometrorrhagia (excessive menstrual periods)
- Occult bleeding (symptomatic of a lower GI bleed), such as that seen
in a slowly bleeding colonic polyp or carcinoma
- Iatrogenic bleeding, such as from repeated blood draws in patients
undergoing a medical evaluation, blood losses associated with repeated
hemodialysis procedures, or excessive blood donations
This is clearly a large list of causes. So, what to do next? There
should be a systematic approach closely coordinated by your primary
care physician to properly evaluate the cause of anemia. A detailed
history and physical is an obvious first step. Questions such as
medication use, your ethnicity and country of origin, and time course
of the anemia will help narrow down the cause.
UptoDate suggests the following laboratory tests in the initial
"Initial testing of the anemic patient should include a "complete"
blood count (CBC). This routinely includes HGB, HCT, RBC count, RBC
indices, and white blood cell (WBC) count. A WBC differential,
platelet count, and reticulocyte count are not part of a routine CBC
in some medical centers; these may have to be ordered separately.
Thus, to avoid confusion, the clinician should specifically request a
CBC with platelets, WBC differential, and reticulocytes." (1)
A blood smear should be ordered to determine if the shape of the RBCs
can tip off any of the aforementioned diseases.
Based on the tests above, the following supplemental tests may then be
ordered if indicated by your physician:
1) More complete evaluation for iron deficiency is indicated when the
history and preliminary laboratory data support this diagnosis. In
this setting, the plasma levels of iron, iron binding capacity, and
ferritin should be measured
2) Hemolysis should be considered if the patient has a rapid fall in
hemoglobin concentration and/or abnormally shaped RBC on the
peripheral smear. The usual findings of hemolysis are an increase in
the serum lactate dehydrogenase (LDH) and indirect bilirubin
concentrations and a reduction in the serum haptoglobin concentration.
Again, these tests should be coordinated by your primary care
physician. A hematology referral may be indicated depending on the
This answer is not intended as and does not substitute for medical
advice - the information presented is for patient education only.
Please see your personal physician for further evaluation of your
Please use any answer clarification before rating this answer. I will
be happy to explain or expand on any issue you may have.
No internet search engine was used in this answer. All sources are
from physician-written and peer-reviewed sources.
1) Schrier. Approach to the patient with anemia. UptoDate, 2003.
Medline Plus - Anemia
Mayo Clinic - Anemia