Tamhsccom: Pathology 6 - Megaloblastic Anemias

Front 1

name some of the sx's of anemia

Back 1

pallor, fatigue, dec'd stamina, rapid pulse, chest pain, cold hands and feet, SOB, orthostatic hypoTN, HA, problems with mental concentration

Front 2

what are all of the sx's of anemia due to?

Back 2

dec O2 content to tissues

Front 3

when evaluating anemia, what is the significance of the MCV?

Back 3

mean cell volume: is used to separate macro- and microcytic anemias

Front 4

what 2 vitamin def's can cause megaloblastic anemia?

Back 4

B12 and Folate (B9)

Front 5

what do def's in B12 or B9 impair that causes megaloblastic anemias

Back 5

impairs conversion of U (RNA) to T (DNA) [B12 and B9 are cofactors for this rxn] so that the cytoplasm matures, Hb is made, but nucleus remains large

Front 6

what type of NP is absolutely characteristic of megaloblastic anemia due to vitamin def?

Back 6

Hypersegmented NP's

Front 7

besides hypersegmented NP's what other cellular abnormalities are seen with megaloblastic anemia?

Back 7

oval macrocytes

Front 8

Vitamin B12 absorption: where is B12 absorbed?

Back 8

Ileum

Front 9

Vitamin B12 absorption: what is B12 found in?

Back 9

meats, milk, eggs (NOT fruits and veggies)

Front 10

Vitamin B12 absorption: what role does Transcobalamin play (types I&III and type II)?

Back 10

Transcobalamin I and III in saliva bind to B12; transcobalamin 2 transports VitB12-Intrinsic factor into intestinal epithelial cells

Front 11

Vitamin B12 absorption: what role dies intrinsic factor play in absorption and where does it come from?

Back 11

Intrinsic factor is secreted for the parietal cells of the stomach; it binds B12 after pancreatic enzymes have stripped off TC 1 &3

Front 12

which factor of B12 absorption probably contributes to why 3-5% of the elderly population is B12 deficient?

Back 12

gastric atrophy may occur in the elderly such that they cannot secrete intrinsic factor which must bind to B12 to be absorbed

Front 13

what is the daily requirement of B12? Of folate?

Back 13

B12 = 2 micrograms; folate = 0.2mg

Front 14

_____________ anemia is when autoantibodies attack the pariental cells of the stomach so that intrinsic factor is not produced

Back 14

pernicious anemia

Front 15

what conditions is pernicious anemia associated with?

Back 15

vitiligo (MJ); Graves disease (thyroid); Addisons disease (adrenal insufficiency); other autoimmune phenomena

Front 16

besides old age, vitiligo, Graves, and Addison's disease, what are other causes of B12 deficiency?

Back 16

dietary def in vegans, gastric resection, small bowel bacterial overgrowth that compete for the utilization of B12; ileal damage with Crohn's disease, sprue, and lymphoma

Front 17

how long does it take to deplete the body of B12 stores? Folate stores?

Back 17

B12 - 4 years, Folate - a few months

Front 18

name some of the sx's of anemia

Back 18

pallor, fatigue, dec'd stamina, rapid pulse, chest pain, cold hands and feet, SOB, orthostatic hypoTN, HA, problems with mental concentration

Front 19

what are all of the sx's of anemia due to?

Back 19

dec O2 content to tissues

Front 20

when evaluating anemia, what is the significance of the MCV?

Back 20

mean cell volume: is used to separate macro- and microcytic anemias

Front 21

what 2 vitamin def's can cause megaloblastic anemia?

Back 21

B12 and Folate (B9)

Front 22

what do def's in B12 or B9 impair that causes megaloblastic anemias

Back 22

impairs conversion of U (RNA) to T (DNA) [B12 and B9 are cofactors for this rxn] so that the cytoplasm matures, Hb is made, but nucleus remains large

Front 23

what type of NP is absolutely characteristic of megaloblastic anemia due to vitamin def?

Back 23

Hypersegmented NP's

Front 24

besides hypersegmented NP's what other cellular abnormalities are seen with megaloblastic anemia?

Back 24

oval macrocytes

Front 25

Vitamin B12 absorption: where is B12 absorbed?

Back 25

Ileum

Front 26

Vitamin B12 absorption: what is B12 found in?

Back 26

meats, milk, eggs (NOT fruits and veggies)

Front 27

Vitamin B12 absorption: what role does Transcobalamin play (types I&III and type II)?

Back 27

Transcobalamin I and III in saliva bind to B12; transcobalamin 2 transports VitB12-Intrinsic factor into intestinal epithelial cells

Front 28

Vitamin B12 absorption: what role dies intrinsic factor play in absorption and where does it come from?

Back 28

Intrinsic factor is secreted for the parietal cells of the stomach; it binds B12 after pancreatic enzymes have stripped off TC 1 &3

Front 29

which factor of B12 absorption probably contributes to why 3-5% of the elderly population is B12 deficient?

Back 29

gastric atrophy may occur in the elderly such that they cannot secrete intrinsic factor which must bind to B12 to be absorbed

Front 30

what is the daily requirement of B12? Of folate?

Back 30

B12 = 2 micrograms; folate = 0.2mg

Front 31

_____________ anemia is when autoantibodies attack the pariental cells of the stomach so that intrinsic factor is not produced

Back 31

pernicious anemia

Front 32

what conditions is pernicious anemia associated with?

Back 32

vitiligo (MJ); Graves disease (thyroid); Addisons disease (adrenal insufficiency); other autoimmune phenomena

Front 33

besides old age, vitiligo, Graves, and Addison's disease, what are other causes of B12 deficiency?

Back 33

dietary def in vegans, gastric resection, small bowel bacterial overgrowth that compete for the utilization of B12; ileal damage with Crohn's disease, sprue, and lymphoma

Front 34

how long does it take to deplete the body of B12 stores? Folate stores?

Back 34

B12 - 4 years, Folate - a few months

Front 35

what is the source of folic acid in our diet?

Back 35

green, leafy veggies (boiling removes); also enriched flour in US

Front 36

what 2 main things can cause a folic acid deficiency?

Back 36

alcoholism and hemolytic anemia

Front 37

who has inc'd requirements?

Back 37

preggers and infants

Front 38

what types of things are seen in the peripheral blood (or not seen)?

Back 38

leukopenia, macrocytic RBCs, anemia, thrombocytopenia, hypersegmented NPs, low reticulocyte count

Front 39

pallor, glossitis, and angular chelitis are signs of A) B12 def, B) folate def, C) both, D) neither

Back 39

C) both

Front 40

which vit def causes neurologic signs?

Back 40

B12 - caused by damage to posterior columns of the spinal cord - loss of vib & pos sense, gait disturbance, megaloblastic madness (indistinguishable from psychosis)

Front 41

T/F: with B12 def, neurological disturbances may occur prior to anemia

Back 41

TRUE

Front 42

with vit def's, folic acid **__does/does not__** correct the neurologic disease; does it correct the anemia?

Back 42

folic acid corrects the anemia, but DOES NOT correct the neuro disease - it makes it worse

Front 43

name some other causes of macrocytic anemia besides vit defs.

Back 43

EtOH, liver disease, excess bile salts --> cholesterol buildup in RBC mem; drugs that impair DNA syn (chemo, AIDs,etc); hypothyroidism, myelodysplastic syndrome, increased reticulocytes (younger are larger than RBCs)

Front 44

Do you give metabolites to confirm deficiency dx if: B12 is dec'd and folate is normal?

Back 44

no, dec'd B12 is consistent with B12 def, therefore no need to confirm dx

Front 45

Do you give metabolites to confirm deficiency dx if: B12 is low to normal and folate is normal?

Back 45

YES b/c B12 def is suspected and you must rule it out!

Front 46

Do you give metabolites to confirm deficiency dx if: B12 is normal and folate is dec'd?

Back 46

no, dec'd folate alone is consistent with folate deficiency

Front 47

Do you give metabolites to confirm deficiency dx if: B12 is dec'd and folate is dec'd?

Back 47

YES!! b/c can't really tell what's going on

Front 48

Do you give metabolites to confirm deficiency dx if: B12 is normal and folate is either almost too low or almost too high?

Back 48

YES b/c this is consistent with folate deficiency OR with an anemia unrelated to vitamin def

Front 49

if you give metobolties (methylmalonic acid and homocysteine) to a pt with suspected vit def, and their conc inc's, then what is confirmed?

Back 49

B12 = confirmed, folate def still possible

Front 50

if you give metobolties (methylmalonic acid and homocysteine) to a pt with suspected vit def, MMA is normal but HC inc's, then what is confirmed?

Back 50

FOLATE DEF

Front 51

if you give metobolties (methylmalonic acid and homocysteine) to a pt with suspected vit def, and both conc's are normal, then what is confirmed?

Back 51

B12 and folate are excluded!!

Front 52

Shillings test - review it!!

Back 52

review Shillings test!