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31 Cards in this Set
- Front
- Back
Extravascular hemolysis
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takes place within macrophages outside vascular stream
Physiologically normal conditions Low-grade chronic hemolytic states |
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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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Role of The Spleen
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Primary site of RBC destruction
especially for less adaptable (spherocytes), less flexible membranes (older cells), inclusions (heinz bodies and howell-jolly bodies) |
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What takes the place of the spleen in splenectomized patients?
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the macrophages of the Liver and Bone marrow
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What is the size of the spleen vasculature?
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3uM
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Heinz bodies
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denatured Hb
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Howell-Jolly bodies
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nuclear remnants
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Haptoglobin (Hp)
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-a Hemoglobin (Hb) binding glycoprotein made in the liver
-an acute phase reactant -absent in the newborn |
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What happens with haptoglobin during hemolysis?
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-Rapid saturation of Hp and rapid clerance (into hepatocyte) of HB/Hp complex
-Low or absent plasma Hp is an indicator of recent or ongoing intravascular hemolysis |
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What binds free hemoglobin in the blood?
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haptoglobin
hemopexin methamalbumin * all of these form complexes and are taken up into hepatocytes |
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hemosiderine
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-storage of hemoglobin
-visualized with prussian blue staining -occurs with low chronic intravascular hemolysis |
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Hemolytic Anemia
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- Shorter life-span of erythrocytes
- Compensatory increase in erythrocyte production (reticulocytosis) |
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Hemolytic Anemia - Etiology
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Intrinsic red cell abnormalities
Extrinsic causes of hemolysis Immune mediated hemolysis Non-immune mediated hemolysis |
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Intrinsic red cell abnormalities
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Hemoglobin Disorders
Red Cell Enzyme Disorders Red Cell Membrane Disorders |
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Hemoglobin Disorders
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Unstable Hemoglobins
Methemoglobinemia Thalassemia Sickle Cell Disease |
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Red Cell Enzyme Disorders
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G6PD Deficiency
Pyruvate Kinase Deficiency |
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Red Cell Membrane Disorders
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Hereditary Spherocytosis
Hereditary Elliptocytosis |
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Extrinsic Causes of Hemolysis
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Immune mediated hemolysis
Schistocytic hemolytic anemia |
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Immune mediated hemolysis
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Warm Reactive Autoimmune Hemolytic Anemia (AIHA)
Cold Agglutinin Disease Paroxysmal Cold Hemoglobinuria (PCH) |
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Schistocytic hemolytic anemia
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Mechanical destruction of RBC as they travel
Hemangiomas (Kasabach-Merritt syndrome) Prosthetic heart valves Microangiopathic hemolytic anemia (MAHA) |
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Microangiopathic hemolytic anemia (MAHA)
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TTP
HUS |
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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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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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Direct Coombs
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Direct Antiglobulin Test
- to identify the presence of immunoglobulins or complement on the surface of the red cells - 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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If the direct coombs test is positive, further tests are done
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IgG only on surface of RBC
IgG and C3complement C3 only on surface cells, antibody on cells may be IgM |
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Indirect Coombs Testing
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take the serum of a patients blood and test the antibodies that are present
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how long does it take babies to develp Antibodies?
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6 months
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Warm Reactive Autoimmune Hemolytic Anemia (AIHA)
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IgG mediated
Extravascular clearance primarily via the reticuloendothelial system (spleen) May be idiopathic or associated with SLE, lymphoid malignancies, immunodeficiency |
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Cold Agglutinin Disease
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IgM mediated
Can be associated with Mycoplasma, EBV Intravascular lysis |
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Paroxysmal Cold Hemoglobinuria (PCH)
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-Acute illness, often after viral URI
>Inciting infections include measles, mumps, varicella, syphilis, Mycoplasma -Caused by cold reactive IgG (Donath Landsteiner Antibody) -Intravascular hemolytic anemia |
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Management of Hemolytic Anemia
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1. Observe growth, development
2. Determine baseline hemoglobin 3. Follow for splenomegaly 4. Educate family regarding risks for gallstones, parvovirus B19 aplastic crisis 5. Folate supplementation 6. Erythrocyte transfusions, intermittent vs chronic 7. Splenectomy 8. Cholecystectomy if symptomatic gallstones |