iron in health disease]]

Question 1

iron important in electron transport e.g.?

Answer 1

mitochondria production of ATP

Question 2

ferric ?

Answer 2

fe3

Question 3

ferrous

Answer 3

fe2

Question 4

iron present in ? (3)

Answer 4

haemoglobin, myoglobin, enzymes eg cytochroms

Question 5

why is iron dangerous?

Answer 5

it induces oxidative stress

Question 6

assessment of iron status

Answer 6

functional - haemoglobin
transport (% saturation with transferrin)
storage (ferritin)

Question 7

what transports iron from donor tissues to tissues expressing receptors ?

Answer 7

transferrin

Question 8

ferritin - large intracellular protein - stores up to ?

Answer 8

4000 iro arims

Question 9

tiny amount of serum ferritin reflects intracellular ferritin synthesis in response to iron - indirect measure of storage iron

Answer 9

y

Question 10

how is iron absorption regulated?

Answer 10

intraluminal factors - solubility or iron, reduction of ferric to ferrous.
mucosal factors - DMT 1 and ferroportin at mucosal surface
hepcidin - major negative regulator of iron uptake.

Question 11

where is hepcidin produced?

Answer 11

liver

Question 12

what is it produced in response to?

Answer 12

iron load and inflammation

Question 13

what facilitates iron export from the enterocyte?

Answer 13

ferroportin

Question 14

what is iron passed on to to be transported elsewhere?

Answer 14

transferrin

Question 15

what does hepcidin do?

Answer 15

down regulates ferroportin

Question 16

normal amount of iron in the body?

Answer 16

4g

Question 17

lack of iron?

Answer 17

angular stomatitis, koilonychia, skin changes

Question 18

iron deficiency can be confirmed by?

Answer 18

combination of anaemia and low storage iron (ferritin)

Question 19

causes of iron deficiency?

Answer 19

diet, bleeding, malabsorption

Question 20

bleeding

Answer 20

menorrhagia, GI tumours, haematuria

Question 21

GI bleeds can occurr without any symptoms

Answer 21

y

Question 22

what is the maximum iron absorption of iron per day?

Answer 22

4-5mg

Question 23

this can balance with GI blood loss i.e. no symptoms

Answer 23

y

Question 24

anaemia of chronic disorders, what happens?

Answer 24

old red cell broken down. increased transcription of ferritin mRNA stimulated by inflammatory cytokines. get increased ferritin synthesis and increase in hepcidin, which blocks ferroportin mediated release of iron

Question 25

results in?

Answer 25

impaired iron supply to marrow erythroblasts and eventually hypchromic red cells

Question 26

primary iron overload?

Answer 26

long term excess iron absorption with parenchymal rather than macrophage iron loading and eventual organ damage

Question 27

what is the parenchyma?

Answer 27

functional part of the organ

Question 28

clinical features of hereditary haemocromatosis?

Answer 28

weakness, fatigue, joint pains, arthritis, cirrhosis, diabetes, cardiomyopathy, impotence

Question 29

haemocromatosis can cause deposits anywhere

Answer 29

hypogonadism, cancer, cirrhosis, cardiomyopathy, diabetes, arthropathy

Question 30

presentation usually in middle age or later

Answer 30

>5g

Question 31

mutations of HFE gene, in particular which mutations?

Answer 31

C282Y, H63D

Question 32

main effect thought to be through?

Answer 32

reduced hepcidin synthesis

Question 33

diagnosis: phenotype

Answer 33

transferrin saturdation >50%, serum ferritin >300 in men or >200 in pre menopausal women

Question 34

why would you consider doing a liver biopsy?

Answer 34

can get cirrhosis in haemacromatosis

Question 35

treatment of hereditary haemacromotosis?

Answer 35

``` weekly phlebotomy (400-500ml) 200-250mg iron ```

Question 36

how much iron in 100ml blood?

Answer 36

50mg

Question 37

initial aim to exhaust iron stores

Answer 37

ferritin below 20

Question 38

thereafter keep ferritin below?

Answer 38

50

Question 39

causes of death in hereditary haemocromotosis?

Answer 39

diabetes, infections, cardiac failure, hepatic failure, bleeding varies, hepatoma

Question 40

first degree relatives: especially siblings risk 1/4

Answer 40

HFE genotype and iron status

Question 41

why important to do family studies?

Answer 41

haemocromatosis may be asymptomatic until irreversible organ damage has occurred. this underlines the importance of family studies

Question 42

secondary iron overload

Answer 42

repeated red cell transfusions, excessive iron absorption related to over active erythropoesis

Question 43

regular blood transfusions

Answer 43

each unit of blood contains 200-250 mg iron

Question 44

patients with thalassaemia may require transfusion every 2-3 weeks lifelong

Answer 44

red cell transfusion (iron overload (total >5g)) or liver >15mg/g dry weight

Question 45

treatment of secondary iron overload?

Answer 45

iron chelating agents (desferrioxamine)

Question 46

why?

Answer 46

venesection not usually an option in already anaemic patients