Iron health and disease

Question 1

functions of iron

Answer 1

oxygen transport in Hb

electron transport in mitochondria

Question 2

Iron is a safe element, true or false

Answer 2

FALSE

it is dangerous

Question 3

why is iron dangerous and what needs to be done as a result

Answer 3

due to production of free radicals and oxidative stress

iron needs to be transported and stored safely

Question 4

how is iron excreted

Answer 4

it is not

there is no mechanism for this

Question 5

where is the majority of iron found in the body

Answer 5

in Hb (haem)

Question 6

why do macrophages have an iron store

Answer 6

because they take up aged RBCs which contain iron

Question 7

how can iron loss occur

Answer 7

physiological bleeding

shedding of skin cells, enterocytes

Question 8

where does iron absorption occur

Answer 8

duodenum - proximal gut

Question 9

which dietary factors increase iron absorption

Answer 9

haem iron transporter - haem iron
ascorbic acid
alcohol

Question 10

which absorbs easier, haem or non-haem iron

Answer 10

haem iron due to presence of haem iron transporter

Question 11

which dietary factors decrease iron absorption

Answer 11

tannins in tea
phytates - nuts, cereal, seeds
calcium

Question 12

Where is Duodenal Cytochrome B enzyme found

What is its function

Answer 12

luminal surface of gut wall

reduces Fe3+ to Fe2+

Question 13

what is the function of DMT-1

Answer 13

transports Fe2+ into duodenal enterocyte

Question 14

what is the function of ferroportin

Answer 14

exports iron out of the enterocyte and passes it onto transferrin

Question 15

what is hepcidin

Answer 15

major negative feedback regulator of iron absorption

Question 16

where is hepcidin produced

Answer 16

in the liver in response to ^ iron or inflammation

Question 17

how does hepcidin work

Answer 17

binds to ferroportin and degrades it meaning iron is trapped in duodenal enterocytes and macrophages
It cannot get to the rest of the body

Question 18

Hepcidin levels are high/low in iron deficiency

Answer 18

low

Question 19

in order to bind to transferrin, iron must be oxidised/reduced

Answer 19

oxidised - in the Fe3+ state

Question 20

How can you assess iron status

Answer 20

functional iron
transported iron
storage iron

Question 21

how do you measure functional iron

Answer 21

Hb concentration

Question 22

how do you measure transported iron

Answer 22

% saturation of transferrin with iron

Question 23

how do you measure storage iron

Answer 23

serum ferritin

Question 24

what is transferrin

Answer 24

protein containing 2 binding sites for iron

to make Fe3+ safer

Question 25

what is the role of transferrin

Answer 25

transports Fe3+ from donor tissue (macrophages, liver, intestines) to cells expressing transferrin receptor eg erythroid marrow

Question 26

what do cells expressing transferrin receptors do

Answer 26

internalise transferrin/Fe3+ complex, use iron and release transferrin back out

Question 27

holotransferrin has bound/unbound iron

Answer 27

bound iron

Question 28

what is the normal % transferrin saturation

Answer 28

20-50%

Question 29

in iron overload, what is % transferrin saturation like

Answer 29

elevated

Question 30

in iron deficiency, what is % transferrin saturation like

Answer 30

reduced

Question 31

What is ferritin

Answer 31

intracellular spherical protein that stores Fe3+

Question 32

what is serum ferritin a marker of

Answer 32

indirect marker of storage iron

Question 33

serum ferritin is also an acute phase protein, true or false

Answer 33

TRUE

Question 34

what is a cause of low ferritin

Answer 34

iron deficiency

Question 35

what are causes of high ferritin

Answer 35

iron overload infection malignancy inflammation

Question 36

What are disorders of iron metabolism

Answer 36

iron deficiency iron malutilisation iron overload

Question 37

how is iron deficiency confirmed

Answer 37

low Hb | low ferritin

Question 38

what is the most important thing to do in iron deficiency anaemia

Answer 38

identify a cause

Question 39

what is a cause of iron malutilisation

Answer 39

anaemia of chronic disease

Question 40

what is the pathophysiology of anaemia of chronic disease

Answer 40

upregulated ferritin levels therefore increase in storage iron even though normal iron is the same hepcidin levels increase which destroy ferroportin and so iron is unable to leave the cells to get to the rest of the body

Question 41

what are the findings in anaemia of chronic disease

Answer 41

high ferritin | low % transferrin saturation

Question 42

what are the categories of iron overload

Answer 42

primary | secondary

Question 43

define iron overload

Answer 43

>5g

Question 44

example of primary iron overload

Answer 44

hereditary haemochromatosis | AR

Question 45

pathophysiology of haemochromatosis

Answer 45

mutation in HFE gene which decreases hepcidin levels | this means there is more iron absorption over a gradual period of time which can result in end organ damage

Question 46

what tests are done for haemochromatosis

Answer 46

genetics transferrin saturation - high ferritin - high

Question 47

symptoms of haemochromatosis

Answer 47

``` arthralgia fatigue cardiomyopathy liver disease DM ```

Question 48

management of haemochromatosis

Answer 48

weekly venesection to exhaust ferritin stores <20 | then keep levels under 50

Question 49

why is haemochromatosis problematic

Answer 49

because you can be asymptomatic and disease is irreversible

Question 50

what are secondary causes of iron overload

Answer 50

repeated red cell transfusions thalassaemias sideroblastic anaemia refracory hypoplastic anaemia

Question 51

management of secondary iron overload

Answer 51

iron chelating drugs