Haematology

Question 1

Red blood cells are produced by which bone marrow cell lineage?

Answer 1

Myeloid progenitor cells (erythroblasts)

Question 2

Briefly describe how haemoglobin is formed

Answer 2

Formed in the mitochondria:

• Iron coupled with transferrin is internalised
• Iron is freed from transferrin
• Iron is translocated into mitochondria
• Iron is then combined with porphyrin ring to form haem

Normal adult Hb is made up of 96-98%: HbA1 = 2 x alpha chains, 2 x beta chains

Question 3

What is the clinical consequence of hypochromic blood cells (blood cells with less colouration)?

Answer 3

Low haemoglobin - haemoglobin is what gives red blood cells their red colouration. The less haemoglobin inside the red blood cell, the paler the cell will be.

Question 4

What type of anaemia does B12 deficiency cause?

Answer 4

Macrocytic anaemia, with presence of oval macrocytes with increased MCV

Question 5

What type of anaemia does iron deficiency cause?

Answer 5

Microcytic, hypochromic anaemia with decreased MCV

Question 6

If a patient has both a microcytic and macrocytic anaemia, their MCV will be normal. How else can you tell the types of anaemia they have on an FBC?

Answer 6

Red Cell distribution width (RDW)

Question 7

What is the significance of fat cells in the bone marrow?

Answer 7

Normal bone marrow has large, white spaces on histology - these are fat cells

They are flexible and provide a space for proliferation of cells to move into

If, on histology, there are very few white spaces, this shows that there is a major increase in proliferation within the bone marrow which is now saturated with blood cells

Question 8

What is the significance of B12 in blood cell production?

Answer 8

B12/folate is important for synthesis of RBCs. It plays an important role in methylation of amino acids - a lot of other cell types will be affected in B12 deficiency

B12/folate is also involved in the production of succinyl-CoA which is involved in Hb synthesis

Question 9

What is the importance of intrinsic factor (IF)?

Answer 9

B12 binds to intrinsic factor in the GI tract. It needs to bind to IF in order to be absorbed. Lack of IF = lack of B12 absorption. This is called Pernicious Anaemia.

Question 10

What do you get if you eat mothballs?

Answer 10

G6PD deficiency