Term
| How long do most RBCs live, what fraction is replaced daily, and where are senescent RBCs destroyed? |
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Definition
| 120 day life; 1% replaced daily (hence ~1% retics in circulation); Senescent RBCs taken out in spleens ReticuloEndothelial System (RES) |
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Term
| *What factors decrease the survivability of RBCs over time? |
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Definition
| RBC membrane resiliency, and the ability of Hemoglobin to remain in the soluble Reduced State |
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Term
| *As RBCs age, senescent cells are removed via the RES in the spleen via what receptor? |
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Definition
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Term
| What are the 4 major roles of the spleen and describe each |
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Definition
| 1) Culling (removal of aged cells), 2) Phagocytosis (removal of cell surface proteins like antibodies or complement), 3) Pitting (remove inclusions like Heinz Bodies and Howell Jolly bodies), 4) Polishing (removal of internal vesicles beneath the erythrocyte membrane that appear as pits) |
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Term
| Splenectomized patients are particularly vulnerable to what ring-shaped parasite inclusion in RBCs that'll cause Anemia? |
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Definition
| Babesia microti (called Babesiosis, from the deer tick) |
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Term
| The pathogenesis of Anemia may be due to what 3 different defects (or a combination of them)? |
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Definition
| Production defect, Maturation defect, or Survival Defect |
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Term
| What are the two contributing factors to a Production defect that leads to anemia? |
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Definition
| BM failure/Stem cell defect (known as Aplastic anemia) or a Decreased Erythropoietin drive (due to Renal failure) |
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Term
| What are the two contributing factors to a Maturation defect that leads to anemia? |
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Definition
| Cytoplasmic maturation or Nuclear maturation defects |
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Term
| What are the two contributing factors to a Survival defect that leads to anemia? |
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Definition
| Excess Hemolysis or Acute blood loss |
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Term
| What is Hemolytic Anemia (HA) defined as and what two factors influence it? |
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Definition
| Anemia due to shortened RBC life span with an appropriate reticulocyte response; Influenced by the Rapidity of onset and Reticulocyte response |
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Term
| What are the different Classifications of Hemolytic Anemia? |
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Definition
| Hereditary vs Acquired; Intrinsic vs Extrinsic; Intravascular vs. Extravascular |
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Term
| *RBC breakdown in Macrophages 11 |
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Definition
|
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Term
| *Intravascular Hemolysis 12 |
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Definition
|
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Term
| What are some of the common clinical findings of HA? |
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Definition
| Pallor, Fatigue, Exercise intolerance, Jaundice, Splenomegaly |
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Term
| What quantity of RBC lysis in mL must occur for hemoglobinuria to occur? |
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Definition
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Term
| Bilirubin elevation in Hemolytic anemia |
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Definition
| Large increase in Unconjugated, small increase in conjugated |
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Term
| Bilirubin elevation in Hepatitis |
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Definition
| moderate increase in both Unconjugated and Conjugated bilirubin |
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Term
| Bilirubin elevation in Gallstone |
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Definition
| Large increase in Conjugated, small increase in unconjugated |
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Term
| What bilirubin will increase, what happens to haptoglobin, what will a peripheral blood smear show, and what will be the bone marrow:erythroid ratio be in HA? |
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Definition
| Increase Unconjugated(indirect) bilirubin, Decrease/Absent Haptoglobin, Polychromasia on blood smear, and Marrow:Erythroid ratio of 1:1 for HA |
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Term
| Normal Bone Marrow: Erythroid raio? |
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Definition
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Term
| Aside from giving Folic Acid for HA treatment, if a Splenectomy is considered, what should be given to the patient? |
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Definition
| Vaccines for Pneumococcus, H. influenzae type B, and N. meningitidis |
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Term
| What can Parvovirus B19 cause? |
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Definition
| Aplastic Crisis (*Erythema infectiosum* or Fifth disease in children) leading to Transiet and Profoundly suppressed erythropoiesis |
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Term
| What are the three main causes of Hereditary Hemolytic Anemia and what aspect of the RBCs do they affect? |
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Definition
| Hereditary Spherocytosis (affects RBC membrane), G6PD deficiency (affects RBC metabolism), and Hb S (a Hemoglobinopathy) |
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Term
| The lipid bilayer of RBCs is attached to a hexagonal protein cytoskeleton consisting of what? |
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Definition
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Term
| What is the most common inherited hemolytic anemia in Europe? |
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Definition
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Term
| What is the defect and result of Hereditary Spherocytosis? |
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Definition
| Defect in Spectrin and Ankyrin resulting in a *Loss of Membrane causing *Spherocytes that are *Less Deformable and get destroyed in spleen (so excess membrane is key for flexibility) |
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Term
| What is the key gross clinical finding in HS and what type of inheritance does it have? |
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Definition
| Pigmented (bilirubin) gallstones; Autosomal Dominant Inheritance |
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Term
| What test is used to diagnose HS and what is the treatment? |
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Definition
| Osmotic fagility test; treatment is a Splenectomy |
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Term
| What is the role of Reduced Glutatione in RBCs? |
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Definition
| Protects against radicals that would otherwise damage RBCs |
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Term
| How is Reduced Glutathione replenished for continued protection in RBCs? |
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Definition
| NADPH keeps glutatione reduced, and NADPH is formed from G6PD |
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Term
| What is the pathogenesis of G6PD deficiency and what type of inheritance is it? |
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Definition
| Diminished levels of Reduced Glutathione won't protect RBCs from Oxidant stress like Fava Beans, causing hemolysis; it is X-linked recessive |
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Term
| G6PD deficiency correlates with increased resistance to what? |
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Definition
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Term
| Which form of G6PD shows decreased activity? |
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Definition
|
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Term
| *What inclusions are present in G6PD deficiency and what stain will show these inclusions? |
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Definition
| Heinz bodies (oxidized/precipitated hemoglobin) seen in Cresyl Violet stain |
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Term
| *The Heinz Bodies found in G6PD deficiency are dealt with in what manner? |
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Definition
| They are removed by Splenic Macrophages forming Bite Cells/Pitting (think biting into Heinz ketchup) |
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Term
| How is G6PD deficiency diagnosed and when should testing be performed? |
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Definition
| By assessing generation of NADPH from NADP; Testing should be Avoided after acute hemolytic episode |
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Term
| What is the most common enzyme deficiency within the Embden-Meyerhoff pathway and what does it result in? |
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Definition
| Pyruvate Kinase Deficiency; results in ATP deficiency in RBCs leading to chronic hemolytic anemia |
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