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39 Cards in this Set
- Front
- Back
A group of disorders characterized by decreased red cell lifespan
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hemolytic anemias
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Clinical feature of hemolytic anemia
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jaundice
dark urine (tea-colored or red) pigmented gallstones ankle ulcers splenomegaly aplastic crises w/ Parvovirus B19 inc requirement for folate |
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two signs of jaundice
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scleral icterus
yellow discoloration of skin |
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post-splenectomy blood findings
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target cells
acanthocytes schistocytes nucleated red cell Howell-Jolly bodies |
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3 classifications of heolytic anemia
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sites of RBC destruction
acquired v. congenital mechanism of red cell damage |
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Differentiate between extravascular v. intravascular hemolysis
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extra has macrophages in spleen, liver, and marrow remove damaned RBC
intra has RBCs rupture within vasculature, releasing free Hb into circulation |
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What would you see in blood for inc red cell production?
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elevated retic ct
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What would you see in bone marrow for inc red cell production?
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erythroid hyperplasia, reduced M/E ratio
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What would you see in bone for inc red cell production?
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deforming changes in skull and long bones (frontal bossing)
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Biochem consequences of hemolysis in general
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elevated LDH levels (of any cell lysis)
elevated unconjugated bilirubin |
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Biochem consequences of intravascular hemolysis
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reduced serum haptoglobin (binding to free Hb)
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Most common defect leading to anemia
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hereditary spherocytosis (dominant)
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What pinches off in hereditary spherocytosis? What is the defect causing this?
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lipid microvesicles pinch off;
defect is in proteins of membrane skeleton |
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How is hereditary spherocytosis dx?
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inc osmotic fragility (lysis occurs at higher tonicity)
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What is the response with splenectomy in hereditary spherocytosis?
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Stops hemolysis, but spherocytes will persist
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2 tx options for hereditary spherocytosis
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folate supplementation
splenectomy |
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What test can be beneficial to spherocytosis?
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MCHC
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What is rate-limiting enzyme in pentose-phosphate shunt?
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G6PD
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In absence of G6PD, what do oxidized Hb to metHb precipitate as? What other path presents with this?
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Heinz bodies; also seen in Thalassemias; spleen pinches off Heinz bodies, leaving bite cell
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Genetic transmission of G6PD deficiency
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X-linked (10-14% of AA men)
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Agents to avoid in G6PD deficiency
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anti-malarials
sulfa drugs dapsone Vitamin K fava beans Naphtha (mothballs) |
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How can African pts have normal G6PD levels while having G6PD deficiency?
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its maximal about 7-10d after exposue, but the body compensates by making reticulocytes, which have normal G6PD levels in younger cells
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Two coatings for autoimmune extravascular hemolysis
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IgG (leads to spherocyte formation) or C3
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Describe characteristics of warm antibodies.
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React best at 37C, do not agglutinate, IgG
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Describe characteristics of cold antibodies.
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best at <32, do cause RBC agglutination, in nose, fingers
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hallmark of autoimmune hemolytic anemia
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positive Coomb's test
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What does Coomb's reagent consist of?
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antibodies to human IgG and C3
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Smear finding in warm-antibody hemolytic anemias
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spherocytes
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Causes of warm-antibody hemolytic anemia
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primary or secondary to another disorder
can be induced by drugs can be associated with immune platelet destruction (Evan's syndrome) |
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warm-antibody hemolytic anemia clinical features
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can have symptoms of anemia, symptoms based on rate of fall of Hb
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Lab findings of warm-antibody hemolytic anemia
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1. inc retic, inc bili, inc LDH
2. positive Coomb's test (both direct and indirect) 3. Spherocytes |
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tx of warm-antibody hemolytic anemia
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immunosuppression is mainstay (corticosteroids, then splenectomy, rituximab as third-line), can transfuse if immediate
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3 mechanisms of drug-induced immune hemolysis
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innocent bystander (quinine, quinidine, isoniazide)
hapten (penicillin and cephalosporin) true autoimmune (alpha-methyldopa, L-DOPA, procainamide) |
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Cold agglutinin disease antibody?
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IgM
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After clumping, what can cold agglutinin present as?
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distal occlusion
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Cold agglutinin disease therapy infection associations
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mycoplasma or mononucleosis
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Tx of Cold agglutinin disease
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keep pt warm, can use immunosuppression, but steroids and splenectomy usually doesn't help
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Hallmark of microangiopathic hemolytic anemia
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presence of schistocytes on peripheral smear
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Causes of microangiopathic hemolytic anemia
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TTP/HUS
DIC malignant HTN Ecclampsia, HELLP syndrome, acute fatty liver of pregnancy vasculitis |