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18 Cards in this Set
- Front
- Back
what happens to haptoglobin in hemolytic anemia? urobilin/urobilinogen?
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- haptoglobin salvages heme b/c heme can be toxic so this decreases
- increased breakdown products such as urobilin & urobilinogen |
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what is intra vs extravascular hemolysis?
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- extravascular = reticuloendothelial system = liver + spleen
- intravascular = heme released into circulation complexing with haptoglobin & excreeted in urine & stool |
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what are some clinical manifestations of hemolytic anemia?
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- pallor, jaundice, enlarged spleen, dark urine
- pigment gallstones, skin ulcers (leg), aplastic crises (associated w/ parvovirus) --> get high fever & low recticulocyte count |
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what are some lab findings in hemolytic anemia?
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- increased reticulocyte count, abnormal peripheral blood smear (red cells w/ nuclei)
- low haptoglobin, increased LDH, increased bilirubin in serum - increased urine hemosiderin in intravascular crisis |
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what happens in hereditary spherocytosis? what is the defect?
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- defects in spectrin, ankyrin, band 3, pallidin --> defective bilayer --> cells become spherocytes
- AD 75%, AR 25% - most common inherited membrane defect |
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what are the labs like in hereditary spherocytosis?
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- increased reticulocyte count
- increased MCHC (ONLY DISORDER THAT DOES THIS) - spherocytes on peripheral smear - abnormal osmotic fragility test (lyse @ low [ ] saline) |
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what happens in hereditary elliptocytosis? what is the defect?
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- AD, defect in spectrin, protein 4.1, glycophorin C --> weakness of RBC cytoskeleton
- milder than HS |
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what happens in G6PD? what is the defect?
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- X-linked
- African variant = milder & only older RBCs effected, Med variant = all RBCs defective - G6PD deficiency fails to generated enough NADPH to salvage reduced glutathione --> lots of oxidative stress to cell |
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what labs do you see with G6PD?
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- ghost cells & bite cells on peripheral smears
- positive heinz body w/ supravital stain - for african variant will come back false neg b/c young red cells have adequate G6PD |
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what happens with pyruvate kinase deficiency?
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- AR, most common defect in glycolysis
- diagnosis is made by enzyme assay |
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what is the difference between G6PD & pyruvate kinase deficiency hemolyic anemia?
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- chronic hemolysis rather than G6PD deficiency which is triggered by something (ie drugs)
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what is the difference between warm & cold AIHA?
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- warm AIHA: caused by IgG antibodies, more likely idiopathic, can fix complement but does not easily activate it
- cold AIHA: caused by IgM antibodies, more likely due to infections or malignancy, fix & activate complement more readily |
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what is the direct coombs test vs indirect coombs test?
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- direct coombs: autoantibodies detected on RBC surface --> red cells agglutinate due to cross linking
- indirect coombs: alloantibodies in serum |
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what coombs test do you use for cold agglutination?
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- C3 positive by not IgG
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which AIHA is responsive to steroids & splenectomy?
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- warm AIHA is responsive, cold AIHA not responsive
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what is a hapten? innocent bystander? autoimmune?
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- hapten: IgG against RBC/drug complex
- innocent bystander: Ab against drug, but cross reacts w/ RBCs - autoimmune: drug induces Abs against RBC antigen |
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what are some non-immune causes of acquired hemolytic anemia?
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- march hemoglobinuria, infections, burns, microangiopathic hemolysis (see schisocytes on blood smear)
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what are microangiopathic hemolysis?
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- RBC damage occurs as they transverse abnormal surfaces
- see shistocytes on peripheral blood smear - hemangioma, artifical valves, DIC (most common cause), TTP (second most common cause) |