Lecture 2: Iron

Question 1

What are the roles of iron in the body?

Answer 1

Iron is an essential mineral. Used in haemoglobin and nicotinamide adenine dinucleotide dehydrogenase.

Question 2

How much iron is in the average body? In what form is the majority of it?

Answer 2

~4g. 75% of this is in the form of haemoglobin and myoglobin.

Question 3

What are the characteristics of iron absorption?

Answer 3

The human body has no way to excrete excess iron. Amount of iron in the body is controlled by the amount of iron absorbed from diet.

Question 4

How much iron does a regular mixed diet contain?

Answer 4

~18mg

Question 5

How much iron is lost per day?

Answer 5

~2mg

Question 6

What are the two ways iron can be classed as in the body?

Answer 6

Inorganic iron and haem iron.

Question 7

Where is most iron absorbed?

Answer 7

In the duodenum.

Question 8

How is inorganic iron absorbed into the epithelia of the duodenum?

Answer 8

Fe3+, which cannot be absorbed, gets reduced to Fe2+. Fe2+ is then absorbed by DMT-1. This is into the

Question 9

How is haem iron absorbed into the epithelia of the duodenum

Answer 9

HCP-1 will be absorbed directly into the apical epithelium.

Question 10

How is iron transported from apical epithelium in duodenum to the bloodstream?

Question 11

Name the mnemonic used to remember

Answer 11

Duodenum - Iron
Jejunum - Folate
Ileum - B12
“Dude is just feeling ill bro”

Question 12

What happens to iron released into the bloodstream?

Answer 12

It will be bound to transferrin.
There is enough transferrin in blood to bind 3000um/dL

Question 13

What is transferrin?

Answer 13

A B-globulin protein, which can carry 2 Fe3+ ions per molecule. Transferrin binds to transferrin-receptors on developing erythrocytes, which is then internalised and iron is turned back into Fe2+ by erythrocytes.

Question 14

Where is iron stored in the body?

Answer 14

Transferrin, previously it was thought hemosiderin was also used, but now believed what was being seen was old degraded transferrin. Hemosiderin is now a name for a variety of iron containing protein deposits.

Question 15

How can hemosiderin be visualised?

Answer 15

Using Perl’s stain.

Question 16

What is ferritin?

Answer 16

A large globular protein that stores ~66% of all body iron. Each molecule can hold around 5000 iron ions. Synthesis is tightly regulated by total body iron levels. (males:13-150 um/L, females: 30-400 um/L).

Question 17

What is a haem group?

Question 18

What is anaemia?

Question 19

What variables can affect results that are not related to disease/pathology?

Answer 19

Pre-analytical
Analytical
Post-analytical

Question 20

What is the largest reason for pre-analytical variation?

Answer 20

Using the.wrong test tube

Question 21

What will happen to blood upon touching a negatively charged surface?

Answer 21

It will coagulate.

Question 22

Why must correct anticoagulant be used?

Question 23

What are the symptoms of anaemia?

Question 24

Anaemia can be caused by an error into any of the 4 main steps of red blood cell production.

Answer 24

Oxygen transport -> Production of erythropoietin -> RBC production -> Haemoglobin concentration ->

Question 25

What is the approach to diagnosing anaemia?

Question 26

What is iron deficiency?

Answer 26

Iron deficiency is the most common cause of anaemia.
Iron deficiency anaemia develops gradually over time, and patients may be in latent iron deficiency for long periods of time.

Question 27

What are the four main causes of iron deficiency?

Answer 27

Decreased intake of Fe - Vegans
Increased Requirement of Fe - Babies
Impaired absorption of Fe - IBD
Chronic blood loss - Women

Question 28

How can impaired absorption be caused?

Answer 28

Inflammatory bowel disease can cause a significant decrease in iron absorption.

Question 29

How may chronic blood loss be present for anaemia to occur?

Question 30

What are the three distinct stages of iron deficiency anaemia?

Answer 30

Stage 1: Progressive loss of stored iron to keep subject working normally. (minimal symptoms)
Stage 2: Once stored iron is exhausted and iron in transferrin is used up. (non-specific or minimal symptoms, with Hb levels dropping slowly)
Stage 3: Frank anaemia (bad symptoms, obvious it is anaemia)

Question 31

What is the impact of low Fe on blood?

Answer 31

Microcytosis - Smaller erythrocytes, should be similar size to nucleus of lymphocyte (

Hypochromia (Hb <100g/L)

Poikilocytosis.

Reticulocytopenia

Target cells.

Question 32

What is the impact of low Fe on the development of new blood cells?

Answer 32

Decreased Fe stores at sites of haematopoiesis.
Erythroid hypoplasia. (less rbcs formed)
Normoblast cytoplasmic abnormalities. (e.g. normoblasts in circulation)

Question 33

What are methods of treating iron deficiency?

Answer 33

Can vary significantly.
Sometimes as simple as dietary changes or more vitamin C.

Question 34

What is anaemia of chronic disorder?

Question 35

Give 2 causes for anaemia of chronic disorder.

Question 36

What can serum ferritin be used for?

Question 37

What are the 3 most common reasons for iron overload?

Answer 37

• Dietary
• Hereditary haemochromatosis
• Transfusion related

Question 38

Why is hereditary haemochromatosis called “the celtic disease”?

Answer 38

Because it is most common in areas such as ireland, cornwall, scotland.

Question 39

What are the four types of hereditary haemochromatosis?

Answer 39

Type 1: Classical, mutation in HFE gene
Type 2: Juvenile, mutation in haemojuvelin (2a) or hepcidin (2b).
Type 3: mutation in TfR-2
Type 4: mutation in ferroportin.

Question 40

Type 1 hereditary haemochromatosis has what 2 genes associated with it?