Anemia III

Question 1

mechanisms of macrocytosis (4)

Answer 1

1. shifting of immature cells (marrow –> peripheral blood) - reticulocytosis
2. abnormalities of DNA metabolism
3. lipid abnormalities
4. unclear mechs - alcohol, hypothyroidism, primary blood disorders

Question 2

why does reticulocytosis cause macrocytic anemia?

Answer 2

reticulocytes have higher MCV than mature RBCs

Question 3

causes of DNA metabolism abnormalities that can lead to macrocytic anemia

Answer 3

vit B12 deficiency
folate deficiency
drugs

Question 4

diagram B12 and folate involvement in DNA metabolism

Answer 4

on paper - see slide 22
folate deficiency –> excess homocysteine
B12 deficiency –> excess homocysteine andmethylmalonic acid

Question 5

causes of vit B12 deficiency

Answer 5

• decreased intake (vegan, alcoholism) - takes yrs to develop
• pernicious anemia
• pancreatic insufficiency
• decrease in absorption surface
• other things that interfere w/ absorption: gastritis, crohn’s, drugs, old age

Question 6

blood smear findings in vit B12 and folate deficiency - IDENTICAL

Answer 6

macrocytic anemia w/ hypersegmented neutrophils

Question 7

how does liver disease cause macrocytosis?

Answer 7

90% of alcoholics have increased MCV!

1. increased lipid deposition in RBC membranes
2. malnourished –> B12 and folate deficiency

Question 8

folate deficiency - differences from B12 deficiency

Answer 8

no neurologic symptoms
methylmalonic acid level NORMAL
develops over 4-5 months (much quicker than B12 def)

Question 9

causes of folate deficiency

Answer 9

decreased oral intake
decreased absorption
drugs (methotrexate, trimethoprim, ethanol, phenytoin)

Question 10

tx for folate deficiency

Answer 10

oral folate
But MAKE SURE THEY DON’T HAVE B12 deficiency - if so, giving them folate can cause subactue combined degeneration of the spinal cord

Question 11

blood smear of an alcoholic

Answer 11

macrocytosis
hypersegmented neutrophils
target cell
acanthocytes