Ch. 11 Megaloblastic Anemias

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Ch. 11 Megaloblastic Anemias
2013-02-10 20:58:30

Megaloblastic anemias
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  1. Megaloblastic anemia
    • Associated with: Vitamin B12 or Folic Acid deficiency.
    • Nutritional deficiency or malabsorption
    • B12 and Folic Acid are needed for DNA synthesis. Cause delayed nuclear maturation.
  2. Asynchronous cell maturation:
    • Mature cytoplasm
    • Immature nucleus
    • Weird looking: Nucleus and cytoplasm don't match
  3. Causes of Vitamin B12 Deficiencies:
    • Increased B12 utilization
    • Malabsorption of B12 from the GI tract.
    • Nutritional deficiency.
    • Pernicious Anemia (PA)
  4. Causes of Folic Acid Deficiency:
    • GI malabsorption
    • Increased utilization (Pregnancy, leukemias)
    • Antimetabolites (drugs that inhibit folic acid)
  5. B12 deficiencies median age at diagnosis:
    60 years old
  6. Folic acid deficiencies most common in:
    Females over 30
  7. B12 transport:
    • Absorption requires GI tract binding proteins.
    • Most important binding proteins is Intrinsic Factor (IF).
  8. Intrinsic Factor:
    • glycoprotein secreted by stomach parietal cells.
    • Stomach acid promotes formation of B12-IF complex.
    • Transcobalamin II (plasma protein) transports B12 to liver and tissues.
  9. B12 and Folic Acid Deficiencies:
    • Associated with: poor diet
    • Malabsorption
    • newborn neural tube defects
    • Pernicious Anemia
  10. Pernicious Anemia caused by:
    • Decreased Intrinsic Factor
    • Gastric atrophy
    • Antibodies against IF
    • Antibodies against parietal cells

    If no intrinsic factor=NO B12
  11. Lab of B12 and Folic Acid Deficiencies:
    • B12 and Folic acid deficiencies have same effects.
    • Decreased=RBC, HGB, HCT, WBC, PLTs, B12, Folic Acid
    • Increased= MCV (oval macrocytes)
    • Aniso, Poik, Ovalocytes, NRBCs, Basophillic stippling, HJ bodies
    • Hyperseg neutrophils
    • Increased plasma LDH enzyme (from hemolyzed RBCs)
  12. Hypersegmented Neutrophil
  13. Top 10:
    • Macrocytic: MCV >96
    • Megaloblastic: specific macrocytic anemia with asynchronous nuclear-cytoplasmic maturation
    • Megaloblastic anemias associated with B12/Folic acid deficiency.
    • Macrocytic Non-megaloblastic anemias seen in liver disease.