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Hemolytic Anemia 1
Lecture 9/25
37
Medical
Professional
09/28/2013

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Term
How long do most RBCs live, what fraction is replaced daily, and where are senescent RBCs destroyed?
Definition
120 day life; 1% replaced daily (hence ~1% retics in circulation); Senescent RBCs taken out in spleens ReticuloEndothelial System (RES)
Term
*What factors decrease the survivability of RBCs over time?
Definition
RBC membrane resiliency, and the ability of Hemoglobin to remain in the soluble Reduced State
Term
*As RBCs age, senescent cells are removed via the RES in the spleen via what receptor?
Definition
CD36
Term
What are the 4 major roles of the spleen and describe each
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)
Term
Splenectomized patients are particularly vulnerable to what ring-shaped parasite inclusion in RBCs that'll cause Anemia?
Definition
Babesia microti (called Babesiosis, from the deer tick)
Term
The pathogenesis of Anemia may be due to what 3 different defects (or a combination of them)?
Definition
Production defect, Maturation defect, or Survival Defect
Term
What are the two contributing factors to a Production defect that leads to anemia?
Definition
BM failure/Stem cell defect (known as Aplastic anemia) or a Decreased Erythropoietin drive (due to Renal failure)
Term
What are the two contributing factors to a Maturation defect that leads to anemia?
Definition
Cytoplasmic maturation or Nuclear maturation defects
Term
What are the two contributing factors to a Survival defect that leads to anemia?
Definition
Excess Hemolysis or Acute blood loss
Term
What is Hemolytic Anemia (HA) defined as and what two factors influence it?
Definition
Anemia due to shortened RBC life span with an appropriate reticulocyte response; Influenced by the Rapidity of onset and Reticulocyte response
Term
What are the different Classifications of Hemolytic Anemia?
Definition
Hereditary vs Acquired; Intrinsic vs Extrinsic; Intravascular vs. Extravascular
Term
*RBC breakdown in Macrophages 11
Definition
11
Term
*Intravascular Hemolysis 12
Definition
12
Term
What are some of the common clinical findings of HA?
Definition
Pallor, Fatigue, Exercise intolerance, Jaundice, Splenomegaly
Term
What quantity of RBC lysis in mL must occur for hemoglobinuria to occur?
Definition
>20-40 ml
Term
Bilirubin elevation in Hemolytic anemia
Definition
Large increase in Unconjugated, small increase in conjugated
Term
Bilirubin elevation in Hepatitis
Definition
moderate increase in both Unconjugated and Conjugated bilirubin
Term
Bilirubin elevation in Gallstone
Definition
Large increase in Conjugated, small increase in unconjugated
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?
Definition
Increase Unconjugated(indirect) bilirubin, Decrease/Absent Haptoglobin, Polychromasia on blood smear, and Marrow:Erythroid ratio of 1:1 for HA
Term
Normal Bone Marrow: Erythroid raio?
Definition
3.5:1
Term
Aside from giving Folic Acid for HA treatment, if a Splenectomy is considered, what should be given to the patient?
Definition
Vaccines for Pneumococcus, H. influenzae type B, and N. meningitidis
Term
What can Parvovirus B19 cause?
Definition
Aplastic Crisis (*Erythema infectiosum* or Fifth disease in children) leading to Transiet and Profoundly suppressed erythropoiesis
Term
What are the three main causes of Hereditary Hemolytic Anemia and what aspect of the RBCs do they affect?
Definition
Hereditary Spherocytosis (affects RBC membrane), G6PD deficiency (affects RBC metabolism), and Hb S (a Hemoglobinopathy)
Term
The lipid bilayer of RBCs is attached to a hexagonal protein cytoskeleton consisting of what?
Definition
Spectrin and Actin
Term
What is the most common inherited hemolytic anemia in Europe?
Definition
Hereditary Spherocytosis
Term
What is the defect and result of Hereditary Spherocytosis?
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)
Term
What is the key gross clinical finding in HS and what type of inheritance does it have?
Definition
Pigmented (bilirubin) gallstones; Autosomal Dominant Inheritance
Term
What test is used to diagnose HS and what is the treatment?
Definition
Osmotic fagility test; treatment is a Splenectomy
Term
What is the role of Reduced Glutatione in RBCs?
Definition
Protects against radicals that would otherwise damage RBCs
Term
How is Reduced Glutathione replenished for continued protection in RBCs?
Definition
NADPH keeps glutatione reduced, and NADPH is formed from G6PD
Term
What is the pathogenesis of G6PD deficiency and what type of inheritance is it?
Definition
Diminished levels of Reduced Glutathione won't protect RBCs from Oxidant stress like Fava Beans, causing hemolysis; it is X-linked recessive
Term
G6PD deficiency correlates with increased resistance to what?
Definition
Malaria
Term
Which form of G6PD shows decreased activity?
Definition
A-
Term
*What inclusions are present in G6PD deficiency and what stain will show these inclusions?
Definition
Heinz bodies (oxidized/precipitated hemoglobin) seen in Cresyl Violet stain
Term
*The Heinz Bodies found in G6PD deficiency are dealt with in what manner?
Definition
They are removed by Splenic Macrophages forming Bite Cells/Pitting (think biting into Heinz ketchup)
Term
How is G6PD deficiency diagnosed and when should testing be performed?
Definition
By assessing generation of NADPH from NADP; Testing should be Avoided after acute hemolytic episode
Term
What is the most common enzyme deficiency within the Embden-Meyerhoff pathway and what does it result in?
Definition
Pyruvate Kinase Deficiency; results in ATP deficiency in RBCs leading to chronic hemolytic anemia
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