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					                                                     Anemia



Objectives for the Laboratory Evaluation of the anemias:


At the completion of these lectures and laboratories the student will be able to:

1. Categorize the anemias based on Red cell indices and morphological characteristics.

2. Perform 10 differentials, including RBC morphology on patients with anemias.

3. Diagnose anemias based on CBC results and Differential results.

4. Discuss the differences between Microcytic Hypochromic, Macrocytic and Normocytic, Normochromic anemias.
Laboratory Analysis of Anemia
I. Microcytic Hypochromic Anemia

  A. Iron Deficiency Anemia

    -most commonly occurring microcytic, hypochromic anemia -causes 90% of micro/hypo anemias
    -chronic blood loss: major cause of iron deficiency anemia
    -Laboratory Findings
      WBC:                                 usually normal
      RBC:                                 micro hypo with anisocytosis and poikilocytosis in varying degrees
      Plts:                                often increased
      Bone Marrow:                         Erythroid hyperplasia
      Retic count:                         Normal or decreased (increases with therapy)
      Serum iron:                          decreased
      Storage iron:                        decreased
      Total Iron Binding Capacity:         increased
      Osmotic Fragility:                   decreased

  B. Thalassemia

    -hereditary disorder
    -abnormal gene causing a decreased rate of synthesis of certain polypeptide chains
    -hemolytic anemia, all other hemolytic anemias are normocytic normochromic
    -Laboratory Findings

      WBC:                                often slightly elevated
      RBC:                                Micro hypo with marked anisocytosis and poikilocytosis (i.e. target
                                          cells, teardrop cells, schistocytes, red cell inclusions)
                                          moderate polychromasia
                                          NRBC's usually present
      Plts:                               often increased
      Bone Marrow:                        erythroid hyperplasia
      Osmotic Fragility                   decreased
      Heinz Bodies                        see with correct stain
      HbF and HbA2                        increased
  C. Sideroblastic Anemia

    -characterized by iron overload or increase in total body iron
    -does not always occur as micro/hypo
    -Dimorphic blood picture (one cell population is micro/hypo, the other is normocytic, normochromic)

     -Laboratory Findings

      WBC:                        usually normal
      RBC:                        Dimorphic blood picture varying anisocytosis and poikilocytosis
      Bone Marrow:                Erythroid hyperplasia, "Ringed" sideroblasts (nucleated RBCs in which iron is
                                  deposited in a ring around the nucleus).
      Serum Iron:                 increased
      Storage Iron:               increased

  D. Anemia of Chronic Disorders

    -starts normocytic normochromic and gradually becomes microcytic, hyporchromic.
    -Associated with: Chronic urinary tract infections, rheumatoid arthritis, chronic leukemia.

II. Macrocytic Anemia

  A. Folic Acid Deficiency

    -Folic Acid is found in eggs, milk, and leafy green vegetables
    -Results in defective DNA synthesis, causing delayed cell division resulting in large, macrocytic RBC's
    -most common cause is a dietary deficiency

  B. Vitamin B12 Deficiency

    -Vitamin B12 is found in eggs, milk and leafy vegetables
    -Results in defective DNA synthesis causing delayed cell division resulting in large macrocytic RBC's
    -Pernicious Anemia - most common cause of vitamin B12 deficiency
    -Pernicious Anemia is caused by lack of intrinsic factor, a substance which is necessary for the
      absorption of Vitamin B12.
    -Megaloblastic Anemia: RBC's are abnormal in the bone marrow and the circulating peripheral blood.
     -Laboratory Findings (Folic Acid and B12)

       WBC:                        often decreased
                                   hypersegmented poly's present
       RBC:                        Macrocytic with moderate anisocytosis and poikilocytosis (teardrop cells,
                                   microcytes and macroovalocytes) RBC inclusions maybe seen (basophilic
                                   stippling, Howell-Jolly Bodies and Cabot rings)
       Plts:                       often decreased
       Bone Marrow:                erythroid hyperplasia, Abnormal red cell precursors (megaloblasts) which are
                                   larger, with a more open chromatin pattern than normal red cell precursors
                                   (normoblasts)


III. Normocytic Normochromic

   A. Hemolytic Anemias

    caused by an increase in red cell destruction due to:
       a) intrinsic disorder: defect in the red cell itself
       b) extrinsic disorder: a hemolytic factor outside the red cell is acting on it.

     1. Intrinsic Disorders

       a. Cell membrane defects

         -Hereditary spherocytosis
         -Hereditary elliptocytosis (ovalocytosis)
         -Hereditary acanthocytosis
         -Hereditary stomatocytosis
         -Paroxysmal nocturnal hemoglobinuria (PNH)

       b. Metabolic defects

         -G6PD Deficiency
         -Pyruvate Kinase Deficiency

       c. Hemoglobin Defects

         -Sickle Cell Disease (sickle cells)
         -Hemoglobin C Disease (Hgb C crystals)
         -Hemoglobin SC Disease (Hgb SC crystals)
2. Extrinsic Disorders

  a.   chemical agents (lead)
  b.   vegetable and animal poisons (fava beans)
  c.   infectious agents (malarial organisms)
  d.   physical agents (burn patients)
  e.   immunological agents (ABO-rh incompatibility)

Laboratory Findings for Hemolytic Anemias

              WBC:            often increased
              RBC:            Normocytic Normochromic
                              Reticulocytosis and Polychromia
                              NRBC's may be present
              Plts:           usually increased
              Bone Marrow:    Erythroid Hyperplasia

3. Acute Blood Loss

  -loss of large amounts of blood over a short period of time
  -WBC increased
  -Plts increased

4. Hypoproliferative Anemia

  -Normal cell forming functions of bone marrow are impaired
  -Aplastic Anemia-Pancytopenia due to bone marrow failure
  -Laboratory Findings

       WBC:                   decreased
       RBC:                   normocytic normochromic
                              morphology normal
       Plts:                  decreased
       Bone Marrow:           hypoplastic

				
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Description: anemia lab findings