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Haemolytic anaemia: Difference between revisions
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'''Haemolytic anaemias''' are a form of [[anaemia]] characterized by the pathologically increased breakdown of RBCs ([[haemolysis]]), reducing their to less than the normal 120 days. To compensate for increased turnover of RBCs the bone marrow can increase the output of RBCs 6 – 8-fold. Anaemia only manifests if the rate of destruction exceeds this increased production rate. | <section begin="clinical biochemistry" />'''Haemolytic anaemias''' are a form of [[anaemia]] characterized by the pathologically increased breakdown of RBCs ([[haemolysis]]), reducing their to less than the normal 120 days. To compensate for increased turnover of RBCs the bone marrow can increase the output of RBCs 6 – 8-fold. Anaemia only manifests if the rate of destruction exceeds this increased production rate. | ||
There exist many types of haemolytic anaemia, both congenital and acquired. | There exist many types of haemolytic anaemia, both congenital and acquired.<section end="clinical biochemistry" /> | ||
== Types == | == Types == | ||
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== Clinical features == | == Clinical features == | ||
In addition to features of [[anaemia]], haemolysis may cause [[jaundice]] and [[Gallstone disease|gallstones]]. Some types of haemolytic anaemia may cause specific symptoms. Haemolysis may occur continuously or intermittently. | In addition to features of [[anaemia]], haemolysis may cause [[jaundice]] and [[Gallstone disease|gallstones]]. Some types of haemolytic anaemia may cause specific symptoms. Haemolysis may occur continuously or intermittently. | ||
<section begin="clinical biochemistry" /> | |||
== Diagnosis and evaluation == | == Diagnosis and evaluation == | ||
A protein called ''[[haptoglobin]]'' is important in the diagnosis of haemolysis. Haptoglobin is a plasma protein which binds to free haemoglobin in the plasma. When there is haemolysis, more haemoglobin is released into the plasma. Haptoglobin in the plasma will bind to the released haemoglobin. This decreases the amount of ''free'' circulating haptoglobin, which is what’s measured in the lab. | A protein called ''[[haptoglobin]]'' is important in the diagnosis of haemolysis. Haptoglobin is a plasma protein which binds to free haemoglobin in the plasma. When there is haemolysis, more haemoglobin is released into the plasma. Haptoglobin in the plasma will bind to the released haemoglobin. This decreases the amount of ''free'' circulating haptoglobin, which is what’s measured in the lab. | ||
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The ''[[Coombs test]]'' is essential in the diagnosis of antibody-mediated anaemias. There are two types of Coombs test, the direct type and the indirect type. The direct Coombs test is positive if there are autoantibodies against the patient’s own RBCs bound to the RBCs in the patient’s blood. The direct Coombs test is positive in immune-mediated haemolytic anaemias. | The ''[[Coombs test]]'' is essential in the diagnosis of antibody-mediated anaemias. There are two types of Coombs test, the direct type and the indirect type. The direct Coombs test is positive if there are autoantibodies against the patient’s own RBCs bound to the RBCs in the patient’s blood. The direct Coombs test is positive in immune-mediated haemolytic anaemias. | ||
The indirect Coombs test is positive if there are autoantibodies against ''foreign'' (not the patient’s) RBCs in the patient’s blood. The indirect Coombs is used to check if the patient’s blood contains anti-D antibodies, which would cause [[haemolytic disease of the newborn]] due to ABO or Rh incompatibility. | The indirect Coombs test is positive if there are autoantibodies against ''foreign'' (not the patient’s) RBCs in the patient’s blood. The indirect Coombs is used to check if the patient’s blood contains anti-D antibodies, which would cause [[haemolytic disease of the newborn]] due to ABO or Rh incompatibility.<section end="clinical biochemistry" /> | ||
[[Category:Haematology]] | [[Category:Haematology]] | ||
[[Category:Internal Medicine (POTE course)]] | [[Category:Internal Medicine (POTE course)]] | ||