Microcytic Anaemia

Question 1

What causes a Microcytic Anaemia?

Answer 1

A Deficient Haemoglobin Synthesis (cytoplamsmic defect)

Question 2

What can cause a Haem group deficiency?

Answer 2

• Lack of Iron for Erythropoiesis.
• Problems with porphyrin synthesis.

Question 3

What causes a Globin subunit Deficiency?

Answer 3

Thalassaemia (trait, intermedia, major)

Question 4

What kind of anaemia causes the prophyrin ring not to be synthesised?

Answer 4

A sideroblastic anaemia.

Question 5

What are the Causes of a Microcytic anaemia?

Answer 5

TAILS
- Thalassaemias
- Anaemia of Chronic disease
- Iron Deficiency anaemia
- Lead poisoning
- Sideroblastic anaemia

Question 6

What is a sideroblastic anaemia?

Answer 6

Excess iron buildup in mitochondria due to failure to incorporate iron into haem.
- Can be hereditary or aquired (lead poisoning, MDS, alcohol excess)
- Causes a problem with Porphyrin synthesis.

Question 7

What is the most common cause of Microcytic anaemia?

Answer 7

Iron Deficiency.

Question 8

What is An anaemia of chronic disease and how does it cause a lack of iron for erythropoiesis?

Answer 8

IL-6 is released due to chronic diseases and increases production of Hepcidin.
Hepcidin down regulates ferroportin expression, reducing the iron absorption and precipitating anaemia of chronic disease.

Question 9

What are some causes of Iron deficiency?

Answer 9

• Insufficient intake to meet physiological needs (more common in women and children due to greater requirements.)
• Losing too much - Bleeding
• Nor absorbing enough - malabsorption (coeliac disease not so common)

Question 10

what colour are cells in a microcytic anaemia?

Answer 10

They are hypochromic (lacking in colour)
- as they contain little Hb.

Question 11

What is circulating Iron bound to in the bloodstream?

Answer 11

transferrin

Question 12

Where does Transferrin transport Iron to and from?

Answer 12

From Donor tissues (Macrophages, intestinal cells and hepatocytes)

Towards tissues expressing transferrin receptors (Esp. erythroid marrow)

Question 13

What does % Iron T-Saturation measure?

Answer 13

Measures Iron supply.
- Reduced in Iron deficiency and Anaemia of chronic disease.
- Increased in Genetic Haemachromatosis.

Question 14

How is Iron stored in the Liver?

Answer 14

In ferritin.
can store up to 4000 ferric ions.

Question 15

What dose a serum ferritin measurement tell us?

Answer 15

Indirect measure of iron in storage.
- it reflects the intracellular ferritin synthesis in response to iron status of the host.

Question 16

How does Anaemia of chronic disease reduce the supply of iron to pathogens?

Answer 16

1. Inflammatory cytokines result in increased transcription of ferritin mRNA
2. Ferritin synthesis is increased
3. Inflammatory cytokines also result in increased plasma hepcidin - blocks ferroportin-mediated release of iron
4. Results in impaired iron supply to marrow erythroblasts and eventually hypochromic red cells

Question 17

What are the sequential consequences of negative iron balance?

Answer 17

1. Exhaustion of iron stores (ferritin falls)
2. Iron deficient erythropoiesis (MCV falls)
3. Microcytic anaemia develops
4. Epithelial changes (effects elsewhere) - skin, koilonychia, angular chelitis

Question 18

What are spoon-shaped nails called?

Answer 18

Koilonychia

Question 19

What is a low MCV value?

Answer 19

<80fL

Question 20

What is a Low MCH value (seen in Microcytic anaemia)?

Answer 20

<27 pg
“hypochromic”

Question 21

What is the inital management of an Iron Deficiency anaemia?

Answer 21

• Improve iron intake.
• Review other medications e.g. anticoagulants, PPIs

Question 22

When is IV Iron considered?

Answer 22

when oral is unsuccessful. (poor tolerance, poor compliance, malabsorption issues, specific situations e.g renal impairment)

Question 23

What are some side effects of oral Iron?

Answer 23

Constipation, Nausea and Vomiting, Abdominal pain, dark stools.

Question 24

How is anaemia of chronic disease managed?

Answer 24

Treating the underlying cause.