Haemolysis

Question 1

what is haemolysis?

Answer 1

red cell destruction

Question 2

two types of haemolysis

Answer 2

1. compensated

2. decompensated (haemolytic anaemia)

Question 3

consequences of haemolysis

Answer 3

bone marrow= erythroid hyperplasia and reticulocytosis

excess breakdown products e.g. bilirubin

Question 4

what does reticulocytosis look like on blood film?

Answer 4

polychromasia

reticulocytes stain blue due to the presence of RNA

Question 5

haemolysis classification based on site

Answer 5

1. extravascular

2. intravascular

Question 6

what does extravascular haemolysis cause?

Answer 6

hyperplasia at site of destruction (hepatosplenomegaly)
release of protoporphyrin
normal products in excess

Question 7

what does protoporphyrin cause?

Answer 7

unconjugated bilirubin- jaundice + gall stones

urobilinogenuria

Question 8

what is intravascular haemolysis?

Answer 8

red cells are destroyed within the circulation spilling their contents

Question 9

what do products of intravascular haemolysis cause?

Answer 9

haemoglobinaemia (free Hb)
methaemalbuminaemia
haemoglobinuria (pink urine that turns black on standing)
haemosiderinuria

Question 10

what is pink urine that turns black on standing seen in?

Answer 10

intravascular haemolysis due to haemoglobinuria

Question 11

what is the consequence of intravascular haemolysis?

Answer 11

abnormal products can be life-threatening

Question 12

causes of intravascular haemolysis

Answer 12

ABO incompatible blood transfusion
G6PD deficiency
severe falciparum malaria

Question 13

diagnosis of hereditary spherocytosis

Answer 13

positive Schumm’s test

schistocytes

Question 14

blood film of G6PD deficiency

Answer 14

bite cells
blister cells
Heinz bodies

Question 15

immune causes of premature red cell destruction

Answer 15

autoimmune haemolysis (warm IgG versus cold IgM)
alloimmune haemolysis

Question 16

mechanical causes of premature destruction of red cells

Answer 16

DIC
HUS (E. coli 0157)
TTP
leaking heart valve/ MAHA
malaria
burns

Question 17

what are microspherocytes?

Answer 17

red cells sheared when pass through capillaries damaged by burns

Question 18

diagnosis of warm IgG and cold IgM AI haemolysis

Answer 18

DAT

Question 19

what is alloimmune haemolysis

Answer 19

immune response to Ab produced (transfusion reaction) or passive transfer of antibody (HDFN)

Question 20

acquired causes of abnormal cell membrane in RBC

Answer 20

1. Zieve’s syndrome
2. vitamin E deficiency
3. paroxysmal nocturnal haemoglobinuria

Question 21

triad in Zieve’s syndrome

Answer 21

haemolysis
alcoholic liver disease
hyperlipidaemia

Question 22

genetic causes of abnormal RBC membrane

Answer 22

hereditary spherocytosis

Question 23

what is hereditary spherocytosis?

Answer 23

defect in RBC membrane proteins causing reduced deformability, increased transit time in spleen and the oxidant environment causes extravascular destruction

Question 24

diagnosis of hereditary spherocytosis

Answer 24

polychromasia

red cells have lost central pallor

Question 25

cause of abnormal red cell metabolism

Answer 25

GP6D deficiency

Question 26

diagnosis of haemolysis

Answer 26

FBC, reticulocyte count, serum unconjugated bilirubin, serum haptoglobins
urinary urobilinogen
blood film
DAT

Question 27

what is haptoglobins?

Answer 27

protein produced by the liver that attaches to free Hb in blood

Question 28

what do spherocytes on blood film indicate?

Answer 28

membrane damage

Question 29

what do red cell fragments on blood film indicate?

Answer 29

mechanical damage

Question 30

what do Heinz bodies on blood film indicate?

Answer 30

oxidative damage

Question 31

what is DAT?

Answer 31

Direct Coomb’s test (looks at antigens on red cell surface)