Macrocytic Anemias Flashcards
Cellular component impaired in megaloblastic anemia
Impaired DNA synthesis affecting all dividing cells of the body
3 general causes for impaired cellular component in megaloblastic anemia
- Vitamin B12 deficiency
- Folate deficiency
- Drugs interfering DNA metabolism
Typical megaloblastic changes in RBC precursors in BM
- Megaloblasts
- Asynchronous maturation
Typical megaloblastic changes in WBC precursors in BM
- Giant forms
- Asynchronous development
Typical megaloblastic changes in PLT precursors in BM
Abnormal, not distinctive
Typical megaloblastic changes in RBC precursors in PB
- Oval macrocytes
- Tear drops
- Howell-Jolly bodies
- Cabot rings
Typical megaloblastic changes in WBC precursors in PB
- Giant forms
- Hypersegmented neutrophils
Typical megaloblastic changes in PLT precursors in PB
May see giant platelets
Correlate BM findings in megaloblastic anemia w/ PB
- Cabot ring
Ineffective HP
Correlate BM findings in megaloblastic anemia w/ PB
- ↓ retic count
↑ ineffective HP
Correlate BM findings in megaloblastic anemia w/ PB
- Howell-Jolly bodies
↑ mitotic forms
Correlate BM findings in megaloblastic anemia w/ PB
- Hyperplastic BM → pancytopenic PB
Ineffective HP
Correlate BM findings in megaloblastic anemia w/ PB
- Hypersegmented neutrophils
↑ mitotic divisions of nucleus
Correlate BM findings in megaloblastic anemia w/ PB
- ↑ MCV
Delayed cell divisions
Correlate BM findings in megaloblastic anemia w/ PB
- Macroovalocytes
Delayed cell divisions and asynchronous maturation
Correlate BM findings in megaloblastic anemia w/ PB
- Teardrop cells
Crowding
Expected results in megaloblastic anemia
- Serum bilirubin
Increased
Expected results in megaloblastic anemia
- Serum LDH
Increased
Expected results in megaloblastic anemia
- Serum iron
Increased
Function of intrinsic factor in vitamin B12 absorption
To absorb B12
Site of intrinsic factor production in vitamin B12 absorption
Secreted by parietal cells of stomach
Site of vitamin B12 absorption
Ileum
Storage organ for vitamin B12
Liver
Extent of body stores for vitamin B12
4-5 years
Clinical features vitamin B12 and/or folate share
- Sore tongue (“beefy red”)
- Lemon-yellow skin…jaundice
Megaloblastic anemia unique to neurological problems
Vitamin B12
Most common cause of vitamin B12 deficiency
Impaired absorption
Defect in pernicious anemia leading to impaired vitamin B12 absorption
Inability of gastric mucosa to secrete IF
How does D. latum or increased bacterial flora in GI tract cause a vitamin B12 deficiency?
Competes w/ use for vitamin B12
Site of absorption of folate metabolism
Jejunum
Extend of body stores for folate metabolism
4-5 months
Most common cause of folic acid deficiency
Poor diet
4 causes of increased requirement of folic acid
- Accelerated HP (hemolytic anemia)
- Neoplastic disease
- Growth
- Pregnancy
3 drugs that interfere w/ absorption of folate
- Folate antagonists (chemotherapy)
- Birth control
- Anti-TB drugs (dilentin, AZT)
RBC morphology expected to see in a patient w/ non-megaloblastic anemia
- Round macrocytes
- Targets, stomatocytes, spur cells
2 causes of non-megaloblastic anemia
- Liver disease and/or alcoholism
- Reticulocytosis
Physiological reason for presence of target cells in PB of a patient w/ liver disease
?
Asynchronous maturation
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Intrinsic factor
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Transcobalamin II
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