Iron deficiency anaemia

Question 1

Causes of iron deficiency: (depletion of iron stores)

Answer 1

1. Insufficient dietary iron
2. Iron requirements increase (e.g. preganacy)
3. Iron lost (slow bleeding from colon cancer)
4. Inadequate iron absorbtion

Question 2

Iron absorbtion

Answer 2

Mainly in duodenum and jejunum

Acid from stomach keeps iron in soluble ferrous (Fe2+) form. Loss of acidity changes it to insoluble ferric form (Fe3+)

Question 3

Causes of iron malabsorption:

Answer 3

PPIs - reduced acidity leads to ferric>ferrous - less soluble

Coeliac disease (inflammation)

Crohn’s disease (inflammation)

Question 4

Most common cause of iron deficiency in adults:

Answer 4

Blood loss:

Women - menstruation (especially those with menorrhagia)

Men - Oesophagitis and gastritis most common cause

Be suspicious of GI tract cancer

Question 5

Most common cause of iron deficiency in growing children:

Answer 5

Dietary insufficiency (requirements exceed intake)
- Especially if diet is low in red meat

Question 6

How does iron travel around the blood stream?

Answer 6

As insoluble ferric ions (Fe3+) bound to a carrier protein called transferrin

Question 7

Total iron biding capacity (TIBC)

Answer 7

Total space on transferrin molecules to bind

Directly related to amount of transferrin in the blood

Question 8

Transferrin saturation:

Answer 8

Transferrin Saturation = Serum Iron / Total Iron Binding Capacity

Expressed as percentage

Question 9

Form iron takes when deposited in cells

Answer 9

Ferririn

Question 10

When does the body release more ferritin?

Answer 10

during inflammation as with cancer

Question 11

Low blood ferritin suggests:

Answer 11

Iron deficiency

Question 12

High blood ferritin?

Answer 12

Difficult to interpret - likely related to inflammation rather than iron overload

Question 13

Normal blood ferritin

Answer 13

Can still have iron deficiency anaemia - especially if there is a reason for it to be raised e.g. infection

Question 14

Serum iron:

Answer 14

Varies throughout the day - higher levels in morning and after eating melas containing iron

Not a very useful measure on its own

Question 15

TIBC/ transferrin measurements

Answer 15

TIBC can be used as a marker of how much transferrin is in the blood (easier than measuring transferrin)

TIBC/transferrin increase in iron deficiency
- Decrease in iron overload

Question 16

Transferrin saturation meanings:

Answer 16

Gives a good measurement of total iron in body

In normal adults will be around 30%
(if low iron in body transferrin saturation decreases)
(If iron levels go up transferrin saturation goes up)

Temporarily increases after iron rich meals or supplementation

Fasting sample gives the best results

Question 17

Causes of falsely raised:

• serum ferritin
• serum iron
• transferrin saturation

Answer 17

Supplementation with iron

Acute liver damage (lots of iron stored in the liver)

Question 18

Management of iron deficiency anaemia:

Answer 18

TREAT UNDERLYING CAUSE IF KNOWN

1. blood transfusion: (fastest)
   - immediately correct anaemia but not underlying cause
   - Carries risk
2. Iron infusion (e.g. “cosmofer”)
   - Very small risk of anaphylaxis
   - Quickly corrects iron deficiency
   - Avoided during sepsis - as iron ‘feeds’ bacteria
3. Oral iron (e.g. ferrous sulfate 200mg 3x day)
   - Slowly corrects deficiency
   - Causes constipation and black coloured stools
   - Unsuitable where malabsorption is the cause of the anaemia

Question 19

Rate of Hb rise when correcting iron deficiency anaemia

Answer 19

10 grams/ litre per week