3. Anemias Due To Failure Of Erythropoiesis - Iron Deficiency

Front 1

What are iron metabolism pathways biased toward?

Back 1

Retention of iron

Front 2

How is iron lost from the body? How much?

Back 2

By shedding of mucosal and epithelial cells - 1-2 mg per day

Front 3

What is an additional way that iron is shed from the body in women?

Back 3

Menstruation

Front 4

What is the daily requirement for iron in
-men
-women

Back 4

Men = 7-10 mg/day
Women = 7-20 mg/day

Front 5

How much nutritional iron is absorbed?

Back 5

15-20%

Front 6

What is the main function of iron absorbed from the diet?

Back 6

To offset the loss from mucosal and epithelial cells.

Front 7

Is the iron intake in many women adequete?

Back 7

Barely

Front 8

What happens to iron absorbed from the intestines?

Back 8

It gets picked up by plasma transferrin

Front 9

In what form is iron
-in food
-when absorbed by enterocytes

Back 9

Food = Ferric Fe3+
To absorb = Ferrous Fe2+

Front 10

What does iron get packaged into in enterocytes?

Back 10

Mucosal ferritin

Front 11

What form is iron when picked up by transferrin in plasma?

Back 11

Fe3+

Front 12

What is the function of Transferrin-Fe3+ complexes?

Back 12

Transfer of iron to the liver for storage and bone marrow for heme synthesis.

Front 13

How much of the total body iron is found in RBCs and RES cells?

Back 13

80-85% (~3 grams)

Front 14

What is the storage site for iron?

Back 14

The liver

Front 15

What is the main way to regulate iron balance in the body?

Back 15

Regulate Absorption

Front 16

What is Fe3+ reduced by for intestinal absorption?

Back 16

Membrane-associated duodenal cytochrome B

Front 17

What is the more prevalent type of iron absorbed from the diet?

Back 17

Heme iron

Front 18

What transporter allows for Fe2+ to be internalized by enterocytes?

Back 18

DMT1 - divalent metal transporter I

Front 19

What transporter allows for basolateral transport of Fe2+ out of enterocytes?

Back 19

Ferroportin I

Front 20

What happens to the Fe2+ after ferroportin transport out of the enterocytes? What enzyme does it?

Back 20

It gets oxidized back to Fe3+
-Iron oxidase Haephestin

Front 21

How is iron transport to plasma different in patients with iron deficiency?

Back 21

It is enhanced

Front 22

What happens to Fe3+ in the plasma?

Back 22

It binds to Transferrin...

Front 23

And the main way to maintain iron balance is:

Back 23

Regulate absorption

Front 24

What are 2 key proteins that regulate iron absorption?

Back 24

-Hepcidin
-HFE

Front 25

What is Hepcidin's function?

Back 25

To inhibit Fe uptake in the duodenum and inhibit release of Fe from Macrophages

Front 26

What disease is associated with mutations in HFE?

Back 26

Hemochromatosis (excess iron absorption)

Front 27

4 classes of iron deficiency:

Back 27

-Dietary lack
-Impaired absorption
-Increased demand
-Chronic blood loss

Front 28

What is the predominant cause of iron deficiency anemia in developed countries?

Back 28

Chronic bleeding due to GI tract lesions

Front 29

What is the predominant cause of iron deficiency anemia in developing countries?

Back 29

Parasitic disease - hookworm or D. latum

Front 30

What are 4 common symptoms of Iron deficiency?

Back 30

-Weakness/pallor
-Koilonychia
-Glossitis
-GI symptoms

Front 31

What is the morphology of Iron deficiency anemia?

Back 31

Hypo/micro

Front 32

What are the lab test findings in iron deficiency anemia? (4)

Back 32

-Low plasma Iron
-Low plasma Ferritin
-High TIBC
-Low transferrin saturation

Front 33

Iron deficiency should always be considered to be caused by __________ until proven otherwise:

Back 33

GI Blood loss

Front 34

What is a common GI disease that causes bloodloss resulting in fe deficiency anemia?

Back 34

Colon cancer

Front 35

What is a more common cause of hypo/micro anemia than iron deficiency?

Back 35

Anemia of chronic disease

Front 36

What are 3 types of chronic diseases associated with impaired RBC production and hence anemia?

Back 36

-Chronic bacterial infection
-Chronic inflammation
-Neoplastic disease

Front 37

What 3 molecules are likely related to the impaired RBC production?

Back 37

-IL1
-TNF
-IFN-y

Front 38

What do IL-1, TNF, AND IFN-y enhance the production of?

Back 38

Hepcidin from the liver

Front 39

And what does Hepcidin from the liver do again?

Back 39

Inhibits the release of iron from macrophages

Front 40

Is anemia of chronic disease always hypo/micro?

Back 40

No, it can be normo/normo

Front 41

What do the iron studies show in Anemia of chronic disease?

Back 41

-Low plasma iron
-HIGH plasma Ferritin
-Low TIBC
-Increased Transferrin saturation

Front 42

What are 2 drugs/chemicals that can cause dose-dependent aplastic anemia?

Back 42

-Benzene
-Chloramphenicol

Front 43

What is the underlying cause of most cases of "idiosyncratic" aplastic anemia?

Back 43

Autoimmune reactions against hematopoietic stem cells

Front 44

What is the best evidence that idiosyncratic aplastic anemia is autoimmune?

Back 44

Most patients responsd at least partially to immunosuppressive therapy

Front 45

When is immunosuppressive therapy for aplastic anemia that is autoimmune most likely to be beneficial?

Back 45

When detected early and given in patients under 30 years old

Front 46

What is a syndrome characterized by normo/normo anemia and almost complete absence of RBC precursors in the marrow called?

Back 46

Pure Red Cell Aplasia (PRCA)

Front 47

What are the 2 general types of PRCA? How are they mainly different?

Back 47

-Transient due to infection; remits spontaneously
-Idiopathic; does not remit spontaneously

Front 48

In what patients are aplastic crises observed in response to bacterial or viral infections?

Back 48

Patients with hemolytic anemias

Front 49

What is a common viral trigger of aplastic PRCA crisis?

Back 49

Parvovirus B19

Front 50

What is the pathogenesis of most non-remitting idiopathic cases of PRCA?

Back 50

Autoimmune mechanisms

Front 51

What is Myelophthisic anemia?

Back 51

The displacement/replacement of hematopoietic tissue by a tumor, granuloma, or fibrosis.

Front 52

What are key clues often seen in the PBS that provide for diagnosing Myelophthisic anemia?

Back 52

-Nucleated RBCs
-Hematopoietic cell precursors

Front 53

What 2 systemic disorders are commonly associated with anemia?

Back 53

-Chronic renal failure
-Chronic hepatic insufficiency

Front 54

Why does chronic renal failure commonly lead to anemia? What type of anemia is it?

Back 54

-Bc it results in EPO deficiency
-Normo/normo

Front 55

What type of anemia is seen in chronic hepatic insufficiency? Why?

Back 55

Macrocytic - because of acquisition of excess lipid in RBC membranes.