erythropoietin independent overproduction of red blood cells uncontrolled

Erythropoietin independent overproduction of red

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erythropoietin-independent overproduction of red blood cells (uncontrolled erythrocyte production) Increased bone marrow sensitivity to growth factors (thrombopoietin & erythropoietin) Diagnosis is confirmed by JAK2 mutation (present in >95% of patients) and low erythropoietin levels à Erythropoietin receptor (cytoplasmic tyrosine kinase non-receptor) à replaces a valine with phenylalinine at position 617 à (also with CML)
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18 UWorld HEMATOLOGY & ONCOLOGY 4. hepatomegaly ® High RBC turnover 1. Gouty Arthritis ® Kidney stones ® Elevated WBC count Folate Deficiency Alcoholic 6-8 lobed neutrophils Anemia within a few weeks Increased Homocysteine NO Methylmalonic Acid (differentiate from Vit. B12) Poor dietary intake Differentiate from Vit. B12 deficiency à NO Neuro deficits/Methylmalonic Acid MCV >100 um Macrocytosis/ Ovalocytosis Can be caused by chronic phenytoin therapy (phenytoin,
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19 UWorld HEMATOLOGY & ONCOLOGY primidone and phenobarbital) à mild megaloblastic anemia involves impaired absorption of folic acid in the small intestine. Folic acid supplementation can effectively prevent this condition. 1. 2. Trimethoprim: It inhibits dihydrofolate reductase and in high doses can cause megaloblastic pancytopenia 3. Methotrexate: Also inhibits dihydrofolate reductase. Folinic acid ( leucovorin } is indicated to reverse the chemotherapeutic anti-folate effect of methotrexate. Pure Red Cell Aplasia (PRCA) Pallor and fatigue (anemia) WBC & Platelets normal Bone marrow precursors appear normal Normocytic anemia Low erythrocytes/reticulocytes Decreased RBC production Low hemoglobin A rare form of marrow failure characterized by severe hypoplasia of marrow erythroid elements in the setting of normal granulopoiesis & thrombopoiesis Inhibition of erythropoietic precursors and progenitors by IgG auto-Ab’s or cytotoxic T-lymphocytes Can be caused by Thymoma ( Thymic Tumor ), lymphocytic leukemias or Parvovirus (attack & destroy proerythroblasts à blasts) Chest scan necessary for thymoma Detect parvo thru anti-B19 IgM Ab’s in serum Intravascular Hemolytic Anemia Older pt. just underwent a valve replacement ê serum haptoglobin à ê because of é circ. of Hb (normally haptoglobin helps uptake Hb into RES system) é serum indirect bilirubin/ LDH é Hb in serum Mechanical trauma to erythrocytes as they circulate thru vasculature Damage can be caused by aortic valve prosthesis or Microangiopathic Hemolytic Anemia (MAHA) Narrowing of vascular spaces due to fibrin formation cause schistocytes Autoimmune Hemolytic Anemia Pt. with pallor, jaundice, splenomegaly, and laboratory findings (low haptoglobin, elevated LDH, indirect Due to autoantibodies to (RBCs). Hemolysis can occur intra- or extravascularly:
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20 UWorld HEMATOLOGY & ONCOLOGY (AIHA) hyperbilirubinemia) are consistent w/ hemolytic anemia Symptoms: ® Fatigue ® Dyspnea ® Splenomegaly ® Anemia with reticulocytosis Labs: ® Normocytic anemia ® é indirect bilirubin with Jaundice ® é serum LDH ® ê serum Haptoglobin ® é Reticulocytes ® Positive Coombs Test
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