Anemia
Due to HemolysisIntroduction
Hemolysis is a process that dissolves red blood cells, so that they live
shorter than the normal 120 days. This can occur because of changes in the red
blood cells themselves or because of factors outside of the red blood cells. Damaged
RBC’s are removed by phagocytic cells, called “reticulocytes”, in the liver,
spleen and in the bone marrow. These reticulocytes are equipped to dismantle the
RBC’s. However, this is done by reutilizing the iron of the hemoglobin molecule
and rescuing the heme part as bilirubin. Normally there are a number of enzymes
that take care of this automatically. The iron is transported to the bone marrow
for reutilization of the iron so that new RBC’s can be made there. The hemoglobin
is converted by the liver into bilirubin and bound to glucuronide. Bilirubin glucuronide
is excreted by the liver into the bile ducts and ends up in the stool where further
enzymatic reactions change it into stercobilin. This gives the stool its brown
color. Each enzymatic step is known to be able to be interrupted by a congenital
abnormality. Some of these abnormalities are of clinical significance, others
are minor. Symptoms The symptoms are similar to other
forms of anemia. However, hemolysis may present with more pronounced symptoms
such as chills, fever, abdominal pain , back pain and general malaise. In severe
cases of hemolysis the patient may have excruciating pain all over and even get
into shock. Jaundice and splenomegaly (enlarged spleen) are often also present.
Diagnostic tests
When blood tests of a patient
with these symptoms show anemia and reticulocytosis (reticulocytes are increased
in the blood), the physician would suspect hemolysis as a possible cause of the
illness. A blood smear is obtained and the hematologist looks for possible causes
of hemolysis. For instance with spherocytosis the pathologist would find spherically
shaped red blood cells. An enlarged spleen is found and there is a family history
of similar findings. Osmotic fragility tests show an increased fragility of the
red blood cell membrane. The Coombs’ tests shows whether there are autoimmune
antibodies that cause autoimmune hemolytic anemia. |
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