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Autoimmune
hemolytic anemia is a group of disorders characterized by a
malfunction of the immune system that produces autoantibodies,
which attack red blood cells as if they were substances foreign
to the body.
Autoimmune hemolytic anemia is an uncommon
group of disorders that can occur at any age. These disorders
affect women more often than men. About half of the time, the
cause of autoimmune hemolytic anemia cannot be determined
(idiopathic autoimmune hemolytic anemia). Autoimmune hemolytic
anemia can also be caused by or occur with another disease, such
as systemic lupus erythematosus, and rarely it follows the use
of certain drugs, such as penicillin.
Destruction of red blood cells by
autoantibodies may occur suddenly, or it may develop gradually.
In some people, the destruction may stop after a period of time;
whereas in other people, it persists and becomes chronic. There
are two main types of autoimmune hemolytic anemia: warm antibody
hemolytic anemia and cold antibody hemolytic anemia. In the warm
antibody type, the autoantibodies attach to and destroy red
blood cells at temperatures equal to or in excess of normal body
temperature. In the cold antibody type, the autoantibodies
become most active and attack red blood cells only at
temperatures well below normal body temperature.
Symptoms
Some people with autoimmune hemolytic anemia
may have no symptoms, especially when the destruction of red
blood cells is mild and develops gradually. Others have symptoms
similar to those that occur with other types of anemia,
especially when the destruction is more severe or rapid. When
severe or rapid destruction of red blood cells occurs, mild
jaundice may also develop. When destruction persists for a few
months or longer, the spleen may enlarge, resulting in a sense
of abdominal fullness and, occasionally, discomfort.
When the cause of autoimmune hemolytic anemia
is another disease, symptoms of the underlying disease, such as
swollen and tender lymph nodes and fever, may dominate.
Diagnosis
Once a doctor diagnoses anemia, increased
destruction of red blood cells is suspected when a blood test
shows an increase in the number of red blood cells that are
immature (reticulocytes). Alternatively, a blood test may show
an increased amount of a substance called bilirubin and a
decreased amount of a protein called haptoglobin.
Autoimmune hemolytic anemia as the cause is
confirmed when blood tests detect increased amounts of certain
antibodies, either attached to red blood cells (direct
antiglobulin or Coombs test) or in the liquid portion of the
blood (indirect antiglobulin or Coombs test). Other tests
sometimes help determine the cause of the autoimmune reaction
that is destroying red blood cells.
Treatment
If symptoms are mild or if destruction of red
blood cells seems to be slowing on its own, no treatment is
needed. If red blood cell destruction is worsening, a
corticosteroid drug such as prednisone
is usually the first
choice for treatment. High doses are used at first, followed by
a gradual tapering of the dose over many weeks or months. When
people do not respond to corticosteroids or when the
corticosteroid causes intolerable side effects, surgery to
remove the spleen (splenectomy) is often the next treatment.
When destruction of red blood cells persists after removal of
the spleen or when surgery cannot be performed,
immunosuppressive drugs, such as
cyclophosphamide
or azathioprine, are used. IVIg is
also
being used to help control the anemias.
Plasmapheresis, which involves filtering blood
to remove antibodies, is occasionally helpful when other
treatments fail (see Controlling Diseases by Purifying the Blood ).
When red blood cell destruction is severe, blood transfusions
are sometimes needed, but they do not treat the cause of the
anemia and provide only temporary relief.
AUTOIMMUNE TREATMENT PAGE
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