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22 Cards in this Set
- Front
- Back
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What is anemia?
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Anemia is a reduction of total circulating red cell mass (2 sd below normal)
- Lower than normal Hmg level or - Lower than normal red cell # or - Lower than normal Hematocrit (% of blood by volume composed of RBCs) |
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What 2 regions of the world have the highest prevalence of anemia?
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SE Asia = 53%
Africa = 39% |
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What are the 4 main causes of anemia?
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1. Iron Deficiency
2. Other nutritional deficiencies (Vit. A, B vitamins, folic acid) 3. Infectious Diseases (Malaria, hookworm, HIV-AIDS, TB) 4. Congenital causes (hemoglobinopathies) |
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Survival of the RBC depends on what external and internal factors?
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Internal Factors: Maintenance of shape, Osmotic Integrity
External Factors: Circulating factors (toxins, Img's), splenic function, vessel wall integrity |
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What is the structure of Hmg?
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- 4 globin chain subunits (2 alpha, 2 beta)
- Heme moiety containing iron |
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Why does a RBC need active metabolism?
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To carry hemoglobin, and maintain it in the functional (reduced) form in order to bind to O2
- To maintain membrane integrity and flexibility |
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What 5 types of metabolic pathways are seen in the RBC?
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1. Enzymes of the glycolytic pathway
2. Pentose Shunt 3. Methemoglobin Reduction (for Fe) 4. Glutathione reduction to protect against oxidative damage 5. Ion pumps in the membrane |
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What hormone stimulates RBC production?
Where is it produced? What cells does it stimulate to produce RBC? |
- Erythropoiten (EPO)
- Produced in the kidneys - Stimulates erythroid cells in marrow to proliferate, resulting in release of new RBCs (reticulocytes) |
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How long is the lifespan of a RBC?
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120 days
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What are 4 specific possible causes of Anemia?
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1. Kidney Disorder (decreased EPO)
2. Erythropoiten (EPO) not able to stimulate marrow 3. Bone Marrow Disorder - decreased production or release of RBCs 4. RBC survival abnormally short - a disorder of the RBC itself or LOSS of RBCs from the body |
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What are the 3 classifications of Anemia based on mechanism?
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1. Diminished Erythropoiesis: the marrow produces too few
2. Increased RBC destruction (hemolysis): the cells have short survival and the marrow is working hard, but cannot compensate with enough new cells 3. Hemorrhagic: loss of RBCs by bleeding |
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What are reticulocytes?
What do they look like under the microscope? |
- Reticulocytes are RBC's newly released from marrow
- Larger than mature RBC's, faintly blue on wright stain |
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What does a low % reticulocyte signify from a patient?
An elevated % reticulocyte? |
Low: marrow is NOT active, there is likely a marrow disorder or EPO disorder
Elevated: means the marrow is healthy, is trying to compensate for a low level of Hmg |
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Why is a corrected reticulocyte count made?
What is its formula? |
Made because in anemia, total number of RBC's is low, so a correction is needed to judge the actual number of reticulocytes made by the marrow
Formula: Reticulocytes x (Actual Hct / Ideal Hct) Ex: Retic 3.5% with Hct of 22% is: 3.5 x (22/45) = 1.7% |
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What are 4 possible causes of Anemia due to diminished production?
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1. Marrow may lack building block of Hmg (Iron, B12, Folate)
2. Marrow may not be able to use Iron: seen in chronic diseases, infections, cancer 3. Deficiency of EPO: renal disease 4. Marrow deficiency in RBC precursors: aplastic anemia, toxins, immune damage |
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Are anemias caused by decrease in production usually acquired or inherited?
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Acquired
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What is marrow hypoplasia or Aplasia?
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- Marrow has low cellularity, fat increased
- Retic count is very low, WBC and platelets also low (bc ALL blood cell affected) |
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What causes Marrow Hypoplasia or Aplasia?
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- usually acquired: chemo, radiation, most of idiopathic
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How is marrow Hypoplasia/Aplasia usually treated?
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Stem cell transplant
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How are Hemolytic Anemia (due to destruction) classified?
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Based on location of the destruction:
1. Extrinsic to the RBC (spleen, trauma) 2. Intrinsic to the RNC: ie sickle cell |
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What are 6 signs and symptoms of anemia?
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1. Low O2 delivery - pallor of skin, nails, eyes. Fatigue, light headed
2. Cardiovascular response: rapid pulse, dyspnea, heart faiulure 3. Hypovolemia - low blood volume (ie blood loss in trauma) 4. BP drop on standing 5. Mental Changes 6. Urine output drops |
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What is seen in acute s. chronic anemia?
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Acute Onset: usually due to hemorrhage, signs of hypovolemia
Chronic Onset: better cardiovascular compensation, may have no symptoms except when under cardiac stress |
