3 - Erythropoiesis and Approach to Anemia

Question 1

gene that enables differentiation into RBCs and megakaryocytes/platelets

Answer 1

GATA-1

Question 2

how long does it take to make a mature RBC?

Answer 2

28 d

Question 3

RBC precursors

Answer 3

Pronormoblast
Basophilic normoblast
Polychromatophilic normoblast
Orthochromatic normoblast
Reticulocyte
Mature RBC

Question 4

what stimulus is detected by the kidney to induce EPO production and release?

Answer 4

low blood oxygenation

Question 5

secondary site of EPO production

Answer 5

liver (10%)

Question 6

type of anemia caused by renal insufficiency

Answer 6

normochromic normocytic

Question 7

what specifically does EPO do to increase RBC production?

Answer 7

prevents apoptosis of RBC precursors

Question 8

4 non-EPO stimulators of erythrogenesis

Answer 8

GM-CSF, IL-3, insulin like growth factor, androgens

Question 9

3 inhibitors of erythrogenesis

Answer 9

IFN gamma, IL1, TNF

Question 10

what makes Darbepoietin different than other recombinant EPOs?

Answer 10

additional glycosylation site > longer half life

Question 11

what protein detects low blood oxygenation to stimulate EPO production?

Answer 11

HIFalpha

Question 12

what protein is responsible for the constitutive release of EPO?

Answer 12

HIFbeta

Question 13

what disease can interfere with HIFalpha signaling / EPO regulation?

Answer 13

von Hippel Lindau syndrome - it is needed for degradation of HIFalpha when oxygenation is high

Question 14

EPO receptor is member of what receptor family

Answer 14

cytokine

Question 15

polycythemia vera

Answer 15

mutation of JAK2 on EPO receptor results in spontaneous dimerization > increased erythropoiesis in absence of EPO

Question 16

2 families of special cytoskeleton RBC proteins

Answer 16

spectrins, band 3 proteins

Question 17

what is the function of spectrins

Answer 17

bind to actin and the inside of the membrane, act like a muscle that improves membrane integrity

Question 18

2,3 DPG stabilizes which form of hemoglobin?

Answer 18

deoxy

Question 19

if each of these factors increases, what will happen to Hb affinity for oxygen?
pH
Temp
2,3 DPG

Answer 19

inc pH > inc affinity
inc temp > dec affinity
inc 2,3 DPG > dec affinity

Question 20

what direction does the curve shift if Hb O2 affinity increases?

Answer 20

left

Question 21

3 types of adult hemoglobins and what subunits they are made up of

Answer 21

A - alpha and beta
A2 - alpha and delta
F - alpha and gamma

Question 22

nl Hb conc

Answer 22

13-17 g/dL

Question 23

nl MCV

Answer 23

80-100 fl

Question 24

nl MCH

Answer 24

27-34 pg

Question 25

nl MCHC

Answer 25

32-36.4 g/dL

Question 26

3 categories of anemia

Answer 26

dilutional (ex pregnancy)
proliferative (due to blood loss or hemolysis)
hypoproliferative (decreased production)

Question 27

nl reticulocyte percentage

Answer 27

1-2%

Question 28

why do you need a corrected retic count?

Answer 28

when you have a lower HCT, a normal number of retics can result in a high percentage. Corrected for different HCT

Question 29

sx of anemia

Answer 29

breathlessness, fatigue, pallor, tachycardia, systolic flow murmur

Question 30

most common cause of hypochromic microcytic anemia

Answer 30

iron deficiency

Question 31

most common cause of megaloblastic anemia

Answer 31

b12 deficiency

Question 32

key lab value suggesting hemolytic anemia

Answer 32

high retic count

Question 33

tx of anemia of chronic renal failure

Answer 33

may need transfusions, usually respond well to exogenous EPO, may require iron supplementation

Question 34

how high should you aim to get a pt w/ kidney disease’s hemoglobin conc?

Answer 34

~10-11. Less than normal because at normal levels they tend to thrombose