Iron Deficiency Anaemia

Question 1

What is the definition of anaemia?

Answer 1

TheWHO defines anaemia as a haemoglobin –
• Below 130 g/L in men over 15 years
• Below 120 g/L in non-pregnant women over 15 years
• Below 110 g/L in pregnant women.

Question 2

What are the symptoms of anaemia?

Answer 2

Major problem is the inability to deliver sufficient oxygen
- leads to fatigue as you can’t carry enough O2 for ATP synthesis

Therefore most adaptations are in cardiovascular system, with increased stroke and tachycardia

Symptoms usually directly proportional to extent of disease
- body adapts very well, so acute anaemia is more dangerous
than chronic

Question 3

What is the impact of IDA in childhood?

Answer 3

Overt iron deficiency in young children is associated with cognitive impairment

Important to identify children at risk ( selective screening is recommended but not compulsory)

Pre-term or low birth weight infants

Infants fed a diet of non iron-fortified infant formula

Infants introduced to cow milk before age 12 months

Children who consume more than 24 oz of cow milk per day

Question 4

What are the causes of IDA?

Answer 4

Occult GI blood loss:
Fe binds to enteric cells in GI tract and is transported. GI blood loss causes increased detachment from cells.
  - Aspirin/NSAID 
  - Colonic carcinoma 
  - Gastric carcinoma 
  - Small  bowel tumour
  - Hookworm

Non-GI blood loss:

• Menstruation
• Blood donation
• Haematuria
• Epistaxis

Malabsorption of Iron:

• Coeliac disease
• Gastrectomy
• H pylori colonisation
• Gut resection
• Bacterial overgrowth

Iron Store Depletion:

• Rapid Growth in infancy and adolescence
• Insufficient diet

Question 5

How is iron distributed in the body?

Answer 5

Total iron concentration in the body – 40–50 mg of iron/kg of body weight

Iron found primarily in:
– RBCs
- macrophages (RBC nucleus is phagocytosed by macrophages 
   that then harvest what's left over)
- hepatocytes (ferritin)
- enterocytes (Iron absorbed here)

~2.1 g is distributed in the haemoglobin

Excess body iron (~ 1 g) is stored in the liver

Iron is lost from sloughing of mucosal and skin cells or during bleeding

There is no regulated mechanism for iron excretion from the body

Question 6

How is iron metabolised?

Answer 6

Iron circulates bound to transferrin (TF)

The liver synthesizes transferrin

Iron bound to TF
– makes iron soluble under physiologic conditions
– it prevents iron-mediated free radical toxicity
– it facilitates transport into cells.

TF is the most important physiological source of iron for red cells.

Question 7

How is iron stored?

Answer 7

Serum ferritin’s major function is to provide a store of iron
– Can store up to 4500 molecules of Fe3+

Body’s primary iron storage compound in the BM, liver and spleen

Good correlation between the total amount of stored iron and the serum ferritin concentration in normal individuals

Question 8

How is IDA treated and managed?

Answer 8

Iron therapy

If patient is responding to iron therapy:
⁻ Reticulocyte count should peak at 1 to 2 weeks
⁻ Haemoglobin should show improvement at 3 to 4 weeks
⁻ Haemoglobin levels should return to normal after 2 to 4 months
⁻ Replacement of iron stores after 6 months

PROVIDED THE UNDERLYING CAUSE IS TREATED