Ch. 5 - Macrocytic anemia Flashcards Preview

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Flashcards in Ch. 5 - Macrocytic anemia Deck (39):
1

What is the MCV in macrocytic anemia?

>100

2

What are folate and Vit B12 used for that causes anemia?

synth of DNA precursors

3

What is the form of folate that circulates in the body?

methylated THF

4

Describe the passage of the methyl group from folate to allow for DNA precursor synth?

methyl-THF to methyl-Vit B12 to homocysteine which then becomes methionine

5

What is another name for vitamin b12?

cobalamin

6

What leads to the size of the cells increasing in megaloblastic anemia?

lack of b12 or folate to make DNA keeps the erythroblast from undergoing its last division, so each cell is a little large

7

Impaired division of granulocytic precursors in megaloblastic anemia leads to (blank)

hypersegmented neutrophils

8

In what other cells do we see megaloblastic changes?

intestinal cells

9

in nonmegaloblastic macrocytic anemia, what changes do you NOT see?

hypersegmented neutrophils and megaloblastic changes in cells other than RBCs

10

Where is folate derived?

green vegetables and some fruits

11

Where is folate absorbed?

jejunum

12

How long does it take for folate deficiency to develop? What does this tell us about the body stores?

takes a few months, body stores are minimal compared to vit. b12

13

What are the three most common causes of folate def?

1. poor diet (kids and elderly)2. increased demand (pregnancy, cancer, hemolytic anemia)3. folate antagonists (methotrexate

14

What enzyme does methotrexate inhibit?

dihydrofolate reductase

15

how many lobes does a PMN need to be hypersegmented?

more than 5

16

What are the lab values in folate def for the following:1. serum folate2. serum homocysteine3. serum methylmalonic acid

1. decreased serum folate2. increased homocysteine (in both folate and B12 def)3. normal methylmalonic acid (increased for b12)

17

Glossitis is a finding in (folate/b12/both)

both

18

What is the dietary source of B12?

complexed with animal protein

19

What enzyme liberates b12 from the protein complex?

salivary amylase

20

B12 is bound by R-binder in what part of the body?

in the mouth

21

Where is intrinsic factor produced? Where does it bind to b12?

made by the parietal cells in the body of the stomach but doesn't bind to b12 until in the terminal ileum

22

Where is b12 absorbed?

absorbed complexed to IF in the terminal ileum

23

How long does it take to develop a b12 def? what does this tell us about the body's stores of b12?

takes years; liver is loaded with b12

24

(blank) detaches b12 from R-binder

pancreatic enzymes

25

how does pancreatic insufficiency cause b12 def. anemia?

no pancreatic enzymes means no separation of b12 from R binder

26

What is pernicious anemia?

autoimmune destruction of the parietal cells of the stomach and under production of intrinsic factor leading to b12 def. anemia

27

What diseases cause damage to the terminal ileum that results in b12 megaloblastic anemia?

Crohn's disease and fish tapeworm Diphyllobothrium latum

28

T/F: there are hypersegmented PMNs in b12 def. anemia

true

29

What is the unique clinical finding that separates b12 def from folate def?

subacute combined degeneration of the spinal cord leading to losses in vibratory sensation and proprioception

30

how does b12 def cause spinal cord damage?

lack of b12 means that methylmalonic acid cannot be converted to Succ-CoA. Methylmalonic acid impairs spinal cord myelinzation

31

What tract of the spinal cord is used for vibratory sensation?

posterior column

32

What tract of the spinal cord is used for proprioception?

lateral corticospinal tract

33

What are the lab values in b12 def anemia for:1. serum b122. serum homocysteine3. methylmalonic acid

1. low b122. high homocysteine3. high methylmalonic acid

34

Where is R-binder and IF resorbed?

terminal ileum

35

Goat milk can cause a decrease in (b12/folate) absorption

folate

36

What drugs often inhibit folate uptake?

5-FUMTXTpm-sfxPhenytoinOcp’setoh

37

Pernicious anemia is seen in what blood group?

Group A

38

What form of hypersensitivity is pernicious anemia?

type II; autoimmune destruction of parietal cells and Abs that block B12-IF binding

39

T/F: anemia is not necessarily present with nonmegaloblastic macrocytosis

true