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Anemia refers to that condition when a person has less
blood in their system than normal. There are many reasons that anemia can
occur. When your health care provider measures your hemoglobin and
hematocrit, they are actually measuring your bodies production of blood
versus the loss of blood.
Anemia can occur due to loss of blood. Red blood cells
only live about 90-120 days. Old red blood cells are disassembled by the
spleen and the parts are recycled back to the bone marrow by the blood
stream to make fresh blood cells. A person can also lose blood due to clots
forming in the blood stream that break red blood cells apart. Prosthetic
devices in the blood stream (mechanical or tissue heart valves,
grafts, greenfield filters, etc). can also cause red blood cells to break
apart. Any kind of blood loss such as bleeding stomach ulcers or colon
polyps or blood in the urine can also cause anemia. Sickle cell disease and
other congenital forms can also cause loss of blood.
Anemia can also occur due to loss of production of blood.
The bone marrow needs an adequate source of iron to make blood out of. Iron
deficiency will make it harder for the bone marrow to make blood. The bone
marrow also needs adequate supplies of Vitamin B12 and folic acid to make
blood.
The bone marrow also needs a stimulus to make blood. That
stimulus is the hormone erythropoietin (you may here us call it EPO in the
clinics). Erythropoietin is primarily made by the kidney in response to
anemia and tells the bone marrow when to make blood. When the kidneys begin
to fail, they make less and less erythropoietin and the patient then
develops anemia. Thanks to recombinant DNA technology, we can now give
erythropoietin (Epogen, Procrit, Aranesp) by injection to treat anemia. Most
patients who have abnormal kidney function will require erythropoietin.
Symptoms
Among the many symptoms of anemia are fatigue, shortness of breath, pounding
heartbeat, rapid heart rate, headaches, loss of appetite, dizziness, ringing
in the ears, weakness, and faintness. Burning of the tongue or a change in
its appearance may also be a clue.
Another sign of anemia may be paleness in the creases of the palms, under
the fingernails, and in the lining of the eye. Very severe cases may be
signaled by swollen ankles; a rapid and weak pulse; pale, clammy skin; and a
feeling of fullness in the neck or abdomen.
Diagnosis
Diagnosis is based on the findings from a physical examination and tests of
the blood (and sometimes the bone marrow) to detect shortages of red blood
cells or hemoglobin. A specific diagnosis is necessary because each type of
anemia has a different cause and so needs a different medical treatment.
Iron-Deficiency Anemia
Iron-deficiency anemia results from a shortage of the mineral iron, which is
necessary to produce hemoglobin. This shortage can be caused by a variety of
conditions, including a drastic blood loss, such as from an accident;
chronic blood loss, such as from a bleeding ulcer; hookworm infestation; and
a diet lacking in good sources of iron.
Women are particularly susceptible to iron deficiency anemia because of the
regular loss of blood during menstruation and the depletion of iron by the
fetus during pregnancy. This type of anemia can be treated with iron
supplements (ferrous sulfate or ferrous gluconate tablets).
Folate-Deficiency Anemia
Folate-deficiency anemia is caused by either insufficient dietary folate,
which is necessary for hemoglobin production, or insufficient absorption of
folate from food. This deficiency may be caused or aggravated by
malnourishment or alcoholism.
Some disorders of the small intestine, such as inflammatory bowel disease,
may also cause it. It is treated with folate and sometimes additional
supplements. Because so many foods are enriched with folate today, this type
of anemia is less common than it used to be.
Pernicious Anemia
Pernicious anemia arises if the body is unable to absorb vitamin B12, which
is necessary for the production of red blood cells in the bone marrow.
Intrinsic factor, a substance that helps to absorb vitamin B12, is lacking
in the stomach of a person suffering from pernicious anemia. Inability to
absorb vitamin B12 can also be caused by some parasites, inflammatory bowel
disease, and diseases of the small intestine. Pernicious anemia is treated
with vitamin B12 injections directly into the bloodstream, so that the
vitamin is not destroyed by stomach acid.
Aplastic Anemia
Aplastic anemia is a serious condition caused by the inability of the bone
marrow to produce white and red blood cells and platelets. Bone marrow
function can be inhibited by cancer or exposure to radioactivity, hazardous
chemicals, or some drugs. This variety of anemia is treated with blood
transfusions and bone marrow transplants.
Hemolytic Anemias
Hemolytic anemias are caused by the destruction of red blood cells. These
anemias can be either acquired (developed over time) or congenital (present
at birth).
Acquired hemolytic anemias can be caused by mismatched blood transfusions, a
drug allergy, cancer, or a serious infection. Treatment of the primary
condition is necessary to treat the resulting anemia. Blood transfusions can
be used to treat the condition temporarily.
Congenital hemolytic anemias are caused by an inherited abnormality in the
red blood cells. The most common type is sickle-cell anemia, a disorder that
predominantly affects black people. In this form of anemia, the red blood
cells, which are sickle shaped instead of disklike, cannot carry enough
oxygen. These cells are also very fragile and hemolyze (break down) easily.
This disease is characterized by crisis periods of severe joint or abdominal
pain and can lead to complications, such as kidney disease, gallstones, and
heart failure. Sickle-cell anemia is treated with painkillers, oxygen, and
transfusions. Avoiding situations in which oxygen may be scarce, such as
high altitudes, is advisable.
Treatment
Your health care providers will monitor your anemia with
frequent blood tests. Any deficiency (iron, vitamin B12, folic acid,
erythropoietin, etc. will be replaced as needed. If your body does not
respond appropriately to therapy, further investigation will be needed. You
may be asked to have your stool tested for blood loss with hemacult or
guaiac cards. If these tests are positive, you may be referred to a
gastroenterologist (stomach doctor). You may also be referred to a
hematologist (blood doctor).
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