Iron in health and disease

Question 1

What is hepcidin?

Answer 1

A major negative regulator of iron uptake

Question 2

What does hepcidin bind to and what effect does this have?

Answer 2

Ferroportin - causes degradation of the ferroportin

Question 3

Where / why is hepcidin produced?

Answer 3

In the liver in response to increased iron load +/- inflammation

Question 4

Where in the body is iron absorbed?

Answer 4

The duodenum

Question 5

Where can most of the iron concentration of the body be found?

Answer 5

In haemoglobin

Question 6

What are the three components assessed in iron status?

Answer 6

• Functional iron
• Transport iron / iron supply to
  tissue
• Storage iron

Question 7

In what two important bodily processes is iron essential?

Answer 7

Oxygen transport - reversible oxygen binding by haemoglobin

Electron transport - mitochondrial production of ATP

Question 8

What is iron present in?

Answer 8

Haemoglobin
Myoglobin
Enzymes - cytochromes

Question 9

What two destructive processes can occur due to iron?

Answer 9

Oxidative stress
Free radical production

Question 10

What is transferrin?

Answer 10

A protein with two binding sites for iron atoms

Question 11

What does transferrin do?

Answer 11

Transports iron from donor tissues to tissues expressing transferrin receptors

Question 12

Which type of marrow is rich in transferrin receptors?

Answer 12

Erythroid marrow

Question 13

What does transferrin saturation measure?

Answer 13

Iron supply

Question 14

What is ferritin?

Answer 14

A spherical intracellular protein that plays a role in iron storage

Question 15

How does serum ferritin act as an acute phase protein?

Answer 15

It will increase with infection, malignancy etc.

Question 16

What will ferritin levels do in iron deficiency?

What will ferritin levels do in iron overload?

Answer 16

Decrease

Increase

Question 17

What is iron misutilisation found in?

Answer 17

Anaemia of chronic disease

Question 18

What is the first sign of negative iron balance?

Answer 18

Exhaustion of iron stores

Question 19

What are the common epithelial changes seen in negative iron balance?

Answer 19

Skin changes - dry, scaly
Koilonychia
Angular stomatitis

Question 20

What are 3 causes of chronic blood loss?

Answer 20

Menorrhagia
Haematuria
Gastrointestinal causes (GI bleeds - ulcers, tumours, NSAIDs)

Question 21

What is occult blood loss?

Answer 21

Gastrointestinal blood loss with no obvious symptoms or signs

Question 22

What is primary iron overload?

Answer 22

Long-term excess iron absorption with parenchymal rather than macrophage iron loading

Question 23

Give an example of primary iron overload?

Answer 23

Hereditary haemochromatosis

Question 24

Give examples of secondary causes of iron overload?

Answer 24

Transfusional causes
Iron loading anaemias

Question 25

What is decreased in hereditary haemochromatosis? What does this result in?

Answer 25

Hepcidin Increased iron absorption

Question 26

What are the clinical features of hereditary haemochromatosis?

Answer 26

Fatigue / weakness Joint pains Impotence Arthritis, cirrhosis Cardiomyopathy Diabetes

Question 27

What typically shows a diagnosis of hereditary haemochromatosis?

Answer 27

Mutations of HFE gene found in investigations

Question 28

What is the treatment of hereditary haemochromatosis?

Answer 28

Weekly venesection to exhaust iron stores

Question 29

What should be done in cases of hereditary haemochromatosis?

Answer 29

Family screening

Question 30

Why is family screening so important in hereditary haemochromatosis?

Answer 30

It if often asymptomatic until irreversible organ damage has occurred

Question 31

What can cause iron-loading anaemias?

Answer 31

Repeated red cell transfusions Thalassaemias Red cell aplasia / myelodysplasia

Question 32

Roughly how much iron is contained in one unit of blood?

Answer 32

250mg

Question 33

What can be done to prevent iron overload in transfusion patients?

Answer 33

Prescribe iron chelating agents

Question 34

How is secondary iron overload treated? What treatment is unsuitable for secondary iron overload?

Answer 34

Iron chelating agents Venesection is not suitable

Question 35

Give an example of a common iron chelating agent?

Answer 35

Desferrioxamine