Vitamin B12/Folate - White

Question 1

Deficiency of vitamin B12 and folate can cause

Answer 1

Severe anemia called megaloblastic anemia

-prevents adequate amounts of DNA

Question 2

Megaloblastic anemia and DNA synthesis

Answer 2

Results in retarded synthesis of DNA

-continual dna synthesis is required for production of numerous erythroblasts

Question 3

Megaloblastic anemia

Answer 3

Retarded synthesis of DNA

Erythroid precursors are stuck in the bone marrow - results in megaloblastic, hyperplasia marrow smears

Question 4

Macrocytic anemia lab values

Answer 4

MCV > 100fl (normal 80-100)
Normal Hb content in relation to size
Blood smear shows macrocytic, normochromic cells
RBC volume is elevated

Question 5

Macrocytic anemia clinical presentation

Answer 5

Lethargy, weakness, yellow or waxy pallor, loss of weight and appetite, diarrhea

Question 6

Megaloblastic macrocytic anemia bone marrow

Answer 6

Large erythroblasts

Hypersegmented neutrophils - 5 vs 3

Question 7

Megaloblasts

Answer 7

Large erythroid precursors
Decrease in mitotic divisions
Nuclear development delayed
Cytoplasmic volume continues to expand

Question 8

Hyperplasia

Answer 8

Many cells

Question 9

Megaloblastic

Answer 9

Big cells

Question 10

Clinical presentation of megaloblastic macrocytic anemia

Answer 10

Neurological sxs: peripheral neuropathy
-pins and needles
-loss memory
Rare - megaloblastic madness

Question 11

No folate

Answer 11

Impaired DNA synthesis

Question 12

3 parts of folic acid

Answer 12

Pteridine
PABA
Chain of glutamic amino acid

Question 13

DHF

Answer 13

Dietary folic acid

Question 14

DHF reduced to ______ by _____

Answer 14

THF by dihydrofolate reductase

Question 15

What is the active form of DHF

Answer 15

THF

Question 16

Function of THF

Answer 16

Transfer carbon units

Question 17

Folate found in

Answer 17

Most foods

-eggs, milk, yeast, leavy

Question 18

Most common cause of folate deficiency is

Answer 18

Inadequate dietary intake

-usually poor and elderly

Question 19

Folate deficiency most common

Answer 19

Poor
Elderly
Alcoholics - little folate
Pregnancy
Drugs

Question 20

Daily folate

Answer 20

50 ug
50-80% is ingested
Absorbed in jejunum
Liver stores 5 to 10 mg

Question 21

Folate trap

Answer 21

If no folate, trapped in N5-methyl-THF

Question 22

Folic acid in intestine reduced

Answer 22

to N5-methyl-THF

Question 23

The primary circulating form of THF in blood stream is?

Answer 23

N5-methyl-THF

Question 24

2 proteins needed for transport of folate into cells

Answer 24

N5-methyl-THF concentrates folates into vesicles

Membrane folate transporter - transfers N5-methyl-THF from the vesicles to the cytosol

Question 25

N5-methyl-THF need to be ______ to enter folic acid cycle as THF

Answer 25

De-methylated

Question 26

N5-methyl-THF requires _________ to become demethylated?

Answer 26

Vitamin B12 (cobalamin)

Question 27

If B12 not available

Answer 27

then folate stuck as N5-methyl-THF | -lots of folate, but can not use it

Question 28

Recommended daily allowance B12

Answer 28

3ug Animal products NOT plants -microorganisms make it

Question 29

Majority of B12 deficiency from

Answer 29

Lack of a protein called intrinsic factor | 85%

Question 30

Dietary B12 binds to proteins called

Answer 30

R-binder proteins | Made by parietal cells

Question 31

Intrinsic factor

Answer 31

Made by parietal cells | Carries B12 ro ileum where receptors bring B12 into body

Question 32

Pernicious anemia

Answer 32

Vit B12 def due to lack of intrinsic factor Gastic mucosa destroyed through auto-immune mechanism Decreased intrinsic factor

Question 33

Type of megaloblastic macrocytic anemia

Answer 33

Pernicious anemia

Question 34

Pernicious anemia lab results

Answer 34

Serum folate < 3 ng/ml | Serum B12 < 350 pg/ml

Question 35

Schilling test

Answer 35

Given oral dose of 57Co-labeled B12 Injection of 1000 ug unlabeled B12 Collect urine 24 hours

Question 36

Schilling test - radioactive B12 absent

Answer 36

Cobalamin (B12) not absorbed | Pernicious anemia

Question 37

Schilling test - radioactive B12 present

Answer 37

Normal absorption of B12 and radioactivity shows in urine | B12 deficient diet is answer

Question 38

Schilling Test Part 2

Answer 38

Add intrinsic factor

Question 39

After Schilling part 2, radioactive B12 present

Answer 39

Pernicious anemia due to lack of intrinsic factor

Question 40

Folate deficiency treatment

Answer 40

Alter diet

Question 41

Pernicious anemia treatment

Answer 41

B12 injections monthly

Question 42

Deficiency of B12 also caused by

Answer 42

Surgical removal of stomach or Crohn's

Question 43

If pt presents with lethargy, weakness, loss of appetite, low Hb%, low RBC count, low serum folate of 0.1 ng/ml and high MVC of 140 fl. Most likely diagnosis?

Answer 43

Megaloblastic macrocytic anemia