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19 Cards in this Set
- Front
- Back
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Extravascular hemolysis
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takes place within macrophages outside vascular stream
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Intravascular hemolysis
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major red cell lysis occurs within the circulation
15% of Hb catabolism follows this pathway Transfusion reactions |
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What is the role of the spleen?
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Primary site of RBC destruction
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When may red blood cells be retained?
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Shape is less adaptable (spherocytes)
Membrane is less flexible (older cells) There are inclusions or particles stuck to the membrane Heinz bodies (denatured Hb) Howell-Jolly bodies (nuclear remnants) |
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What is haptoglobin?
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Hp is a Hemoglobin (Hb) binding glycoprotein made in the liver
It is an acute phase reactant Absent in the newborn |
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What happens to the hemoglobin/haptoglobin complex after the intravascular hemolysis occurs?
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The Hp/Hb complex is internalized by the hepatocyte
Globin and Hp are degraded into a.a for recycling Heme is catabolized to bilirubin and iron |
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What is a low or absent haptoglobin level indicative of?
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Recent or ongoing intravascular hemolysis
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What is hemopexin and methemalbumin?
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Free excess of heme is bound to hemopexin and albumin and taken by hepatic receptors for catabolism
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what is hemosiderin?
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In low chronic intravascular hemolysis ferritin accumulates in the tubular cells
Hemosiderin via Prussian blue staining |
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What is hemoglobinuria and under which conditions do you see it?
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During massive intravascular hemolysis Hb appears in the urine (haemoglobinuria)
Can precipitate and cause ARF (acute remal failure) |
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What are some characteristics of hemolytic anemia?
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Compensatory increase in erythrocyte production (reticulocytosis), patients will have normal hemoglobin but higher retic count
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What are some causes of hemolytic anemia?
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Intrinsic red cell abnormalities
Extrinsic causes of hemolysis Immune mediated hemolysis Non-immune mediated hemolysis |
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What are some intrinsic abnormalities in red blood cells which can sause hemolytic anemia?
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Red Cell Membrane Disorders
Hereditary Spherocytosis Hereditary Elliptocytosis Red Cell Enzyme Disorders G6PD Deficiency Pyruvate Kinase Deficiency- cells die quicker than normal Hemoglobin Disorders Unstable Hemoglobins Methemoglobinemia Thalassemia Sickle Cell Disease |
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What are some extrinisic causes of hemolysis which can cause hemolytic anemia?
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Immune mediated hemolysis
Warm Reactive Autoimmune Hemolytic Anemia (AIHA) Cold Agglutinin Disease Paroxysmal Cold Hemoglobinuria (PCH) Schistocytic hemolytic anemia: Mechanical destruction of RBC as they travel Hemangiomas (Kasabach-Merritt syndrome) Prosthetic heart valves Microangiopathic hemolytic anemia (MAHA) TTP HUS |
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What is the clinical presentation of hemolytic anemia?
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Pallor
Icterus, jaundice Fatigue Splenomegaly Gallstones Cholecystitis Dark urine May present with parvovirus associated aplasia Family history |
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What are the increased Nutritional Requirements of Chronic Hemolysis?
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Greatest requirement is for folic acid and lowest body stores (10 day storage)
Amino acid to make globin chains (normal nutritional status) B12 (10 years storage) No increase Fe requirement since it is “recycled” and stored in bone marrow |
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What is the purpose of the direct coombs test?
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to identify the presence of immunoglobulins or complement on the surface of the red cells
determines if the hemolytic anemia is non immune mediated |
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How is the direct coombs test performed?
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Sample from the patient is mixed with reagent that has antibodies against human immunoglobulins and complement.
If agglutination forms, the test is +. |
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What are the three main patterns found in a positive direct commbs test
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If the test is positive, further tests are done.
Three main patterns: IgG only on surface of RBC IgG and C3complement C3 only on surface cells, antibody on cells may be IgM |
