Iron deficiency and anaemia of chronic disease

Question 1

What is a haematinic?

Answer 1

A nutrient required for the formation of blood cells in the process of hematopoiesis. The main hematinics are iron, Vitamin B12, and folate.

Question 2

How much iron do you need per day to maintain the production of red blood cells?

Answer 2

20 mg/day

Question 3

Although iron from RBCs is recycled, state how iron can still be lost under normal, non-pathological conditions? How much iron would compensate for these losses in men and women?

Answer 3

Desquamation of cells in the skin and gut
Bleeding (menstruation is one of the largest causes of loss of iron from the body in women)

Men - need 1mg/day
Women - need 2mg/day

Question 4

How much iron does the human diet normally provide?

Answer 4

12-15 mg/day

Question 5

State some natural foods that are high in iron.

Answer 5

Meat and fish
Vegetables
Whole grain cereal
Chocolate

Question 6

Which form of iron cannot be absorbed?

Answer 6

Fe3+ (ferric)

Can only absorb ferrous iron Fe2+

Question 7

What effect does orange juice and tea have on iron absorption?

Answer 7

Orange juice helps

Cups of tea make it worse

Question 8

In what form is iron absorbed from meat and fish?

Answer 8

Absorb iron already in the haem form

Question 9

State three systemic factors that increase iron absorption.

Answer 9

Iron deficiency
Anaemia/hypoxia
Pregnancy

Question 10

What effect does gastric acid in the duodenum have on iron absorption?

Answer 10

Gastric acid lowers the pH in the proximal duodenum, enhancing the solubility and uptake of ferrous iron via the enzymatic conversion from ferric iron

Question 11

Which channel/transporter, on the basal membrane of intestinal epithelial cells, allows movement of iron into the circulation?

Answer 11

Ferroportin

Question 12

What is a key regulator of iron absorption that inhibits the action of ferroportin? Why is it responsive to iron?

Answer 12

Hepcidin

Iron is part of the complex that switches on hepcidin transcription

Question 13

How is iron stored within cells?

Answer 13

In ferritin micelles

Question 14

What transports iron in the circulation?

Answer 14

Carrier protein called transferrin

Question 15

State three parameters involving transferrin that can be measured that give an indication of iron status

Answer 15

Transferrin
Transferrin Saturation
Total Iron Binding Capacity (TIBC)

Question 16

What is the normal transferrin saturation?

Answer 16

20-40%

Question 17

Where is erythropoietin produced and what effect does it have?

Answer 17

Kidneys (stimulated by tissue hypoxia)

Stimulates an increase in red blood cell precursors; makes them survive longer; stimulates growth and differentiation

Question 18

What is anaemia of chronic disease?

Answer 18

Anaemia that is seen in patients with chronic disease (i.e. patients who are unwell)

Question 19

What typical signs of anaemia will these patients NOT have?

Answer 19

They will NOT be bleeding
They will NOT be haematinic deficient (but note that serum iron may be low, just not total body)
They will NOT have any bone marrow infiltration

Question 20

State some laboratory signs of being ill.

Answer 20

Raised Erythrocyte Sedimentation Rate (ESR)

Raised acute phase proteins (increase or decrease their serum concentration in response to inflammation);

• ferritin
• FVIII
• fibrinogen
• immunoglobulins

Question 21

State some causes of anaemia of chronic disease.

Answer 21

Chronic infections – e.g. TB/HIV
Chronic inflammation – e.g. SLE, rheumatoid arthritis
Malignancy
Miscellaneous (e.g. cardiac failure)

Question 22

What is the underlying cause of ACD?

Answer 22

• ACD is due to the increased inflammatory cytokine release (e.g. TNF-𝛼, various interleukins)

Cytokines:

• prevent the usual flow of iron from duodenum to red cells, hence, blocking iron utilisation
• stop erythropoietin increasing
• Increase production of ferritin to stop iron flowing out of cells
• increase death of red cells

Question 23

State four broad causes of iron deficiency

Answer 23

1. Bleeding e.g. menstrual/GI bleeding
2. Increased use e.g. growth/pregnancy
3. Dietary deficiency e.g. vegetarian
4. Malabsorption e.g. coeliac

Question 24

Under what conditions are full GI investigations performed?

Answer 24

Good diet and no coeliac antibodies and…

• Male
• Women over 40
• Post-menopausal women
• Women with scanty menstrual loss

Question 25

List 5 laboratory parameters that are used to determine the type of anaemia

Answer 25

1. MCV
2. Serum iron
3. Ferritin
4. Transferrin (=TIBC)
5. Transferrin saturation

Question 26

State three potential causes of a low MCV.

Answer 26

Iron deficiency
Anaemia of chronic disease
Thalassemia trait

Question 27

How does serum iron help distinguish between the three causes of microcytic anaemia?

Answer 27

Iron deficiency – LOW serum iron
ACD – LOW serum iron
Thalassaemia trait - normal

Question 28

How would you confirm thalassemia trait?

Answer 28

Haemoglobin electrophoresis

Question 29

Describe the difference in ferritin levels in iron deficiency and anaemia of chronic disease.

Answer 29

Iron deficiency – LOW

ACD – HIGH (because it is an acute phase protein

Question 30

Why is ferritin not always reliable? What should be checked in addition?

Answer 30

Some people may have a chronic disease and be bleeding e.g. rheumatoid arthritis and a bleeding stomach ulcer. In this case the ferritin may appear normal.
You need to check the other signs of infection/inflammation such as ESR and CRP to see if there is an underlying condition causing a rise in acute phase proteins

Question 31

Describe the difference in transferrin in iron deficiency and ACD.

Answer 31

Iron deficiency – HIGH

ACD – LOW/NORMAL

Question 32

Describe the difference in transferrin saturation in iron deficiency and ACD.

Answer 32

Iron deficiency – LOW

ACD – NORMAL

Question 33

What is the confirmed diagnosis of a man of any age with a low ferritin? What are the subsequent investigations?

Answer 33

Iron deficiency

He needs upper and lower GI endoscopies to look for the source of the bleeding

Question 34

State some other investigations that can be performed, following diagnosis of iron deficiency

Answer 34

• Antibodies for coeliac disease
• Check for urinary blood loss
• Duodenal biopsy
• Anti-helicobacter antibodies