Peripheral Blood Smear

Anisocytosis

  • Definition: red blood cells of different sizes
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Helmet Cells

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Hypochromia

  • Iron Deficiency Anemia (see Iron Deficiency Anemia, [[Iron Deficiency Anemia]])
  • Thalassemia
    • Alpha Thalassemia Minima (see Thalassemias, [[Thalassemias]]): slight hypochromia may be seen
    • Alpha Thalassemia Minor (see Thalassemias, [[Thalassemias]])
    • Beta Thalassemia Minor (see Thalassemias, [[Thalassemias]])
    • Beta Thalassemia Intermedia (see Thalassemias, [[Thalassemias]])
    • Beta Thalassemia Major (see Thalassemias, [[Thalassemias]])

Leukoerythroblastic Smear

  • Definition: smear with precursor cells of the myeloid and erythroid lineage, which usually indicates the presence of extramedullary hematopoiesis (predominantly in the spleen)
  • Etiology
    • Bone Marrow Infiltration (see Pancytopenia, [[Pancytopenia]])
    • Myelofibrosis/Myelophthisis (see Pancytopenia, [[Pancytopenia]])
    • Severe Stress
      • Blood Loss
      • Hemolysis
      • Infection
  • Features
    • Anisocytosis: RBC’s are of different sizes
    • Immature Myeloid Cells
    • Immature Nucleated RBC’s
    • Megakaryocytic Fragments
    • Poikilocytosis: abnormally-shaped RBC’s
    • Polychromasia (Polychromatophilia): large number of grayish-blue RBC’s, indicative of RBC immaturity
    • Teardrop-Shaped RBC’s (Dacrocytes)

Poikilocytosis

  • Definition: red blood cells of different shapes
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Scistocytes

  • Definition: fragmented RBC’s
  • Etiology
    • Hemolytic Anemia (see Hemolytic Anemia, [[Hemolytic Anemia]])
      • Thrombotic Thrombocytopenic Purpura (TTP) (see Thrombotic Thrombocytopenic Purpura, [[Thrombotic Thrombocytopenic Purpura]])
      • Hemolytic-Uremic Syndrome (HUS) (see Hemolytic-Uremic Syndrome, [[Hemolytic-Uremic Syndrome]])
      • Mechanical Damage to Red Blood Cells
        • Macroangiopathic Hemolytic Anemia
        • Microangiopathic Hemolytic Anemia (MAHA)

Spherocytes

  • Definition: presence of spherocytes indicates loss of RBC membrane surface area in excess of loss of cell volume -> spherocytes are a feature of many hemolytic anemias
  • Etiology
    • Interaction of Membrane-Antibody Complex with Reticuloendothelial System
      • Autoimmune Hemolytic Anemia (AIHA)
      • Alloimmune Hemolytic Anemia: ABO incompatibility
    • Microangiopathic Hemolytic Anemias (MAHA)
    • Oxidant Injury
    • Phospholipases or Other Membrane Active Enzymes
    • Othe

Spur Cells

  • Definition
  • Etiology
    • Spur Cell Anemia

Target Cells (Codocytes, Mexican Hat Cells)

  • Definition
  • Etiology
    • Asplenia (see Asplenia, [[Asplenia]]): splenic macrophages normally clear opsonized, deformed, and damaged red blood cells -> if splenic macrophage function is abnormal/absent because due to splenectomy, altered red blood cells will not be removed from the circulation appropriately
      • Auto-Splenectomy Resulting from Sickle Cell Disease (see Sickle Cell Disease, [[Sickle Cell Disease]])
      • Post-Splenectomy
    • End-Stage Liver Disease (ESLD) (see End-Stage Liver Disease, [[End-Stage Liver Disease]]): decreased lecithin/cholesterol acyltransferase (LCAT) activity, resulting in increased cholesterol:phospholipid ratio -> absolute increase in surface area of the red blood cell membrane
    • Hemoglobin C Disease
    • Iron Deficiency Anemia (see Iron Deficiency Anemia, [[Iron Deficiency Anemia]]): decrease in hemoglobin content relative to red blood cell surface area
    • Thalassemias (see Thalassemias, [[Thalassemias]]): decreased hemoglobin content relative to red blood cell surface area
      • Alpha Thalassemia Minor (see Thalassemias, [[Thalassemias]])
      • Beta Thalassemia Minor (see Thalassemias, [[Thalassemias]])

Teardrop Cells (Dacrocytes)

  • Beta Thalassemia Minor (see Thalassemias, [[Thalassemias]])

References

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