Anaemia and polycythaemia

Question 1

Define “anaemia”

Answer 1

A reduction in the amount of haemoglobin in a given volume of blood below what would be expected in comparison with a healthy subject of the same age and gender

Question 2

Recall 4 MECHANISMS of anaemia

Answer 2

1. Reduced red cell/ Hb production
2. Pooling of red cells in large spleen
3. Blood loss
4. Reduced red cell survival

Question 3

What is defective in microcytic anaemia? Recall 3 causes

Answer 3

Haemoglobin synthesis
Defects in haem synthesis: iron deficiency
Defects in globin synthesis: alpha thalassaemia, beta thalassaemia

Question 4

What name is given to anaemia caused by abnormal haemopoiesis? What classification is it given and why?

Answer 4

Megaloblastic anaemia (failure of DNA synthesis)
MACROCYTIC - delay in maturation of the nucleus while the cytoplasm continues to mature and the cell continues to grow

Question 5

What is the most common cause of megaloblastic eryhtropoiesis?

Answer 5

B12 deficiency

Question 6

Recall 7 possible causes of macrocytic anaemia

Answer 6

1. Vit B12 def.
2. Folic acid def.
3. Recent major blood loss
4. Drugs that interfere with DNA synthesis
5. Alcohol toxicity
6. haemolytic anaemia
7. Liver disease

Question 7

Why would haemolytic anaemia be macrocytic?

Answer 7

Number of reticulocytes increased, and they are 20% bigger than mature cells

Question 8

What could be a cause of pooling of red cells in an enlarged spleen?

Answer 8

Portal cirrhosis

Question 9

Recall 3 possible causes of normacytic normachromic anaemia

Answer 9

1. Recent blood loss
2. Failure of red cell production
3. Pooling in hypersplenism

Question 10

Recall 3 possible causes of rec cell production failure

Answer 10

1. Bone marrow suppression by cancer drugs
2. Bone marrow infiltration by cancer
3. early stages of a deficiency (B12/FA/ renal fx)

Question 11

Recall 5 hereditary causes of haemolytic anaemia

Answer 11

1. Protein deformation
2. Spherocytosis
3. Sickle Cell
4. Pyruvate kinase deficiency
5. G6PD deficiency

Question 12

Recall the aetiology of hereditary spherocytosis leading to haemolytic anaemia

Answer 12

1. Cells lose section of membrane in spleen
2. Premature removal from spleen
3. Bone marrow responds by increasing activity –> polychromasia and reticlocytosis
4. Cells more likely to haemolyse when osmotic pressure applied

Question 13

What is G6PD essential for in erythrocytes?

Answer 13

Prevention of oxidant damage

Question 14

Recall 3 possible extrinsic oxidants that may cause G6PD deficiency

Answer 14

1. Drugs
2. Broad beans
3. Napthalene (moth balls)

Question 15

Who is most at risk of G6PD deficiency and why?

Answer 15

Hemizygous males, as the G6PD gene is on the X chromosomes

Question 16

Describe the blood film of someone with haemolytic anaemia caused by G6PD deficiency

Answer 16

Many irregularly contracted cells

Heinz bodies

Question 17

What causes Heinz bodies?

Answer 17

Denatired DNA

Question 18

Describe the aetiology of autoimmune haemolytic anaemia

Answer 18

Production of AutoIg-M which is directed at red cells

IgM recognised by splenic macrophages and phagocytosed, leading to loss of membrane and spherocytosis

Question 19

Recall the 5 principles of diagnosis for haemolytic anaemia

Answer 19

1. Normachromic
2. Normacytic or macrocytic
3. Morphologically abnormal red cells
4. increased red cell breakdown
5. Increased bone marrow activity

Question 20

Recall the aetiology of biliary system complications in haemolytic anaemia

Answer 20

Heamolysis > bilirubin production increased > jaundice + gall stones

Question 21

What 2 things might be seen on the blood film of someone with haemolytic anaemia?

Answer 21

Spherocytes

Increased #reticulocytes

Question 22

Recall the first line of treatment for haemolytic anaemia

Answer 22

Corticosteroids and other immunosuppressants

Question 23

What measures are elevated in polycythaemia

Answer 23

HCt
Hb
Red cell count

Question 24

WHat is the difference between pseudopolycythaemia and true polycythaemia?

Answer 24

Pseudopolycythaemia - results from decreased plasma vol

True polycythaemia - results from increased red cell number

Question 25

Recall 4 possible causes of polycythaemia

Answer 25

1. Blood doping
2. Too much erythropoietin
3. Renal carcinoma
4. Abnormal bone marrow fx (eg polycythaemia vera)