Macrocytic anaemia

Question 1

What is the predominant feature of a true macrocytic anaemia?

Answer 1

Defects in DNA synthesis and nuclear maturation; relative preservation of RNA and Hb synthesis

Question 2

If haemoglobin synthesis is relatively unaffected in a true macrocytic anaemia, what causes the anaemia?

Answer 2

Reduced division and increased apoptosis; fewer cells, less haemoglobin.

Question 3

Which 2 cycles link B12 and folate?

Answer 3

Folate cycle & methionine cycle

Question 4

State sources of B12 and folate respectively, along with their sites of absorption

Answer 4

B12 = meat, dairy products and dairy products; only animal products.
- Terminal ileum
Folate = green vegetables, nuts, yeast and liver.
- Duodenum/Proximal jejunum

Question 5

Describe the pathogenesis of PA

Answer 5

Autoimmune condition resulting in the destruction of gastric parietal cells; deficiency of IF causes B12 malabsorption and deficiency in that vitamin.

Question 6

Name 3 drugs which can cause folate deficiency

Answer 6

Phenytion, sodium valproate, methotrexate.

Question 7

In the neurological symptoms of B12, which tract remains intact?

Answer 7

Spinothalamic

Question 8

What would be seen in the FBC and blood film of a macro anaemia patient?

Answer 8

FBC: Elevated MCV with a low haematocrit.

Blood film: macrovalocytes and hyperhsegmented neutrophils.

Question 9

State 4 causes of non-megaloblastic macrocytosis

Answer 9

• Alcohol
• Liver disease
• Hypothyroid
• Marrow failure