Haemolysis

Question 1

What is meant by haemolytic anaemia?

Answer 1

Decompensated haemolysis

- Increased rate of red cell destruction exceeding bone marrow capacity for red cell production

Question 2

List two consequences of haemolysis?

Answer 2

1. Erythroid hyperplasia (increased done marrow red cell production)
2. Excess red cell breakdown products such as bilirubin

Question 3

In what two ways does the bone marrow respond to haemolysis?

Answer 3

1. Reticulocytosis

2. Erythroid hyperplasia

Question 4

Where does extravascular haemolysis usually take place?

Answer 4

Spleen and liver

Question 5

Where does intravascular haemolysis take place?

Answer 5

Within the circulation

Question 6

In intravascular or extravascular haemolysis more common?

Answer 6

Extravascular

Question 7

What is released in excess in extravascular haemolysis?

Answer 7

Protoporphyrin

- unconjugated bilirubin

Question 8

In which condition would you see pink urine, which turns black when left standing?

Answer 8

Intravascular haemolysis due to haemoglobinuria

Question 9

Are the products of intravscular haemolysis normal or abnormal?

Answer 9

Abnormal

Question 10

What investigations would you do if you suspected haemolysis?

Answer 10

1. FBC and blood film
2. Reticulocyte count
3. Serum unconjugated bilirubin
4. Serum haptoglobins
5. Urinary urobilinogen

Question 11

Are serum haptoglobins increased or decreased in someone who has haemolysis?

Answer 11

Decreased

Question 12

What cells on a blood film suggest oxidative damage?

Answer 12

Heinz cells

Question 13

What cells on a blood film suggest mechanical damage?

Answer 13

Red cell fragments

Question 14

What types of autoimmune haemolysis are caused by IgG antibodies?

Answer 14

Autoimmune disorders such as SLE
Lymphoproliferative disorders such as B cell lymphoma
Penicillins

Question 15

What types of autoimmune haemolysis are caused by IgM antibodies?

Answer 15

Infections (EBV)

Question 16

What test do you do to identify IgG antibodies to red cells?

Answer 16

Direct Coombs Test

Question 17

What two ways could you get alloimmune haemolysis?

Answer 17

1. Immune response, the antibody is produced - eg to a haemolytic transfusion reaction
2. Passive transfer of antibody as seen in haemolytic disease of the newborn, ABO incompatibility, Rh D

Question 18

Is the immediate haemolytic transfusion reaction mediated by IgM or IgG?

Answer 18

IgM (intravascular)

Question 19

Is the delayed haemolytic transfusion reaction mediated by IgM or IgG?

Answer 19

IgG (extravascular)

Question 20

What three conditions can cause acquired haemolysis due to membrane defects in the red blood cells?

Answer 20

1. Liver disease (Zieve’s syndrome)
2. Vitamin E deficiency
3. Paroxysmal Nocturnal Haemoglobinuria

Question 21

Deficiency of which enzyme causes a failure of red blood cells to cope with oxidant stress?

Answer 21

Glucose 6 phosphate dehydrogenase deficiency

Question 22

What kind of mutation causes sickle cell anaemia?

Answer 22

Point mutation is the beta globin chain

Question 23

What are the haematological findings in haemolysis?

Answer 23

Raised unconjugated bilirubin
Decreased haptoglobin
Increased lactate dehydrogenase
Increased urobilinogen
Reticulocytosis + polychromasia

Question 24

What % of cell of should be reticulocytes?

Answer 24

2%