Iron-deficiency anaemia

Question 1

Causes

Answer 1

Iron deficiency is the most common cause of anaemia worldwide.

The most common causes are;

1. Chronic blood loss;

• haemorrhoids
• menorrhagia
• peptic ulcers
• cancer, etc.

2. Poor diet.

Question 2

Haemological investigations: typical findings

Answer 2

Microcytic, hypochromic red cells

Anisocytosis (variation in size) and poikilocytosis (shape)

Low s. iron

↑ Iron-binding capacity

Low s. ferritin (NR: ♀ 15–200 mcg/L; ♂ 30–300 mcg/L, the most useful index)

↑ soluble transferrin receptor factor

Question 3

Haem iron in food

Answer 3

Haem iron

• Lamb kidneys—-15mg/100g
• Beef mince—-2mg/100g
• Chicken breast—-1.9mg/100g

Non-haem iron (harder to absorb)

• Tofu—-2.5mg/100g
• Baked beans—-1.2mg/100g
• Spinach (raw)—-4.4mg/100g

Question 4

Treatment, oral

Answer 4

Correct the identified cause

Iron preparations:

–oral iron (preferred method), e.g.

Ferro-Gradumet 325 mg (o) daily

• with orange juice or ascorbic acid until Hb is normal
• can combine with folic acid

Maltofer, not funded in NZ

• 100 mg tablets
• 50 mg/5 mL syrup

Question 5

Parenteral iron

Answer 5

Avoid transfusion if possible. considered when;

• oral iron is contraindicated, ineffective or not tolerated

– is best reserved for special circumstances and with specialist advice.

IM can cause a ‘tattoo’ effect.

Give 0.5–1 g ferric carboxymaltose IV (consider cover with IV hydrocortisone 30 mins before)

Simplified Method (for pts of body weight ≥ 35 kg);

Hb Body Weight

g/L 35 kg to < 70 kg > 70 kg

<100 1,500 mg 2,000 mg

100 to < 140 1,000 mg 1,500 mg

>140 500 mg 500 mg

Question 6

Pharmacokinetic properties of iron Rx

Answer 6

The iron is absorbed by a controlled mechanism in the small intestine and unabsorbed iron is excreted via faeces.

After absorption, it is immediately bound to transferrin and distributed to the sites of demand, or stored as ferritin in liver and spleen.

Most iron is incorporated into the oxygen-transport protein haemoglobin (Hb) during erythropoiesis in the bone marrow.

The iron from erythrocytes is recycled at the end of their life span.

Question 7

Hepcidin?

Answer 7

A hepatic-derived peptide hormone

the dominant regulator of iron absorption and incorporation into erythrocytes

induces internalisation and degradation of the iron transporter protein ferroportin

• thus limiting iron absorption and release.

Ferroportin is heavily expressed in 2 sites on the;

• basolateral membrane of enterocytes
• macrophages
• thereby regulates both iron absorption and tissue redistribution

Hepcidin expression is induced by inflammation

Many diseases (eg IBD) where failure to adequately absorb iron contributes to iron def and IDA

• oral iron Rx unlikely to be effective if hepcidin is blocking enteral absorption
• in which cases parenteral iron would be appropriate

Question 8

Ferinject

Answer 8

An iron (III)-hydroxide core contained in a carbohydrate shell;

confers stability to the FCM complex

Reduces the allergic side effect ( only mix with max 100 ml NS, otherwies gets washout)

allows a slow and controlled release of iron from within the cells of the reticuloendothelial system.

This stability limits amount of labile (unbound) iron entering the circulation.

• Labile iron is toxic to cells

Question 9

Contraindication to iron Rx

Answer 9

• Known hypersensitivity to iron supplements
• Iron overload e.g.
• haemochromatosis
• haemosiderosis

• Disturbances in iron utilisation e.g.

• lead anaemia
• sidero-achrestic anaemia
• thalassaemia

• Anaemia not caused by iron deficiency e.g.

• haemolytic anaemia
• megaloblastic anaemia

Question 10

Response

Answer 10

Anaemia responds after ~2 wks and is usually corrected after 2 mths

Oral iron is continued for 3–6 mths to replenish stores

Monitor progress with regular s. ferritin

s. ferritin >50 mcg/L generally indicates adequate stores