Haemolysis

Question 1

Define haemolysis

Answer 1

premature RBC destruction

Question 2

Why are RBCs susceptible to damage

Answer 2

biconcave shape
no mitochondria
no nucleus

Question 3

define compensated haemolysis

Answer 3

increased red cell destruction is compensated by increased red cell production
Hb is maintained

Question 4

which is more common compensated or decompensated haemolysis

Answer 4

decompensated

Question 5

what is decompensated haemolysis also known as

Answer 5

haemolytic anaemia

Question 6

define haemolytic anaemia

Answer 6

increased red cell destruction exceeding bone marrow’s capability to produce red cells

Question 7

list consequences of haemolysis

Answer 7

erythroid hyperplasia

excess RBC breakdown products

Question 8

can you measure red cell survival directly?

Answer 8

no, rely on consequences of haemolysis

Question 9

what is the bone marrow’s response to haemolysis

Answer 9

reticulocytosis

erythroid hyperplasia

Question 10

Reticulocytes have a nucleus, true or false

Answer 10

FALSE

they contain RNA fragments

Question 11

what are some causes of reticulocytosis

Answer 11

haemolysis
haemorrhage
Iron treatment in Fe deficiency anaemia

Question 12

how can haemolysis be classified

Answer 12

according to site of destruction

• extravascular
• intravascular

Question 13

where does extravascular haemolysis occur

Answer 13

in the reticuloendothelial system

- mainly spleen and liver

Question 14

where does intravascular haemolysis occur

Answer 14

within the circulation

Question 15

which is more common intra or extravascular haemolysis

Answer 15

extravascular

Question 16

signs of extravascular haemolysis

Answer 16

hepatomegaly 
splenomegaly 
jaundice 
gallstones 
urobilinogenuria

Question 17

products of extravascular haemolysis are normal/abnormal

Answer 17

normal products present in excess

Question 18

signs of intravascular haemolysis

Answer 18

haemoglobinaemia
methaemalbuminaemia
haemoglobinuria
haemosiderinuria

Question 19

what is a feature of haemoglobinuria

Answer 19

pink urine that turns black on voiding

often mistaken for haematuria

Question 20

products of intravascular haemolysis are normal/abnormal

Answer 20

abnormal

Question 21

causes of intravascular haemolysis

Answer 21

ABO incompatible blood transfusion
G6PD deficiency
severe falciparum malaria
PNH, PCH

Question 22

causes of extravascular haemolysis

Answer 22

everything else

eg autoimmune haemolytic anaemia

Question 23

How can you confirm haemolytic state

what are the findings

Answer 23

FBC - low Hb
Blood film 
Reticulocytes - high 
Unconjugated bilirubin - high 
Serum haptoglobin - low 
Urinary urobilinogen - high

Question 24

what can blood film show in haemolysis

Answer 24

membrane damage - spherocytes
mechanical damage - red cell fragments
oxidative damage - Heinz bodies
other - HbS

Question 25

what are some causes of haemolysis according to site of red cell defect

Answer 25

premature RBC destruction: immune or mechanical
membrane defects: congenital or acquired
metabolism defects: congenital or acquired
Hb abnormality

Question 26

how can immune causes of haemolysis be classified

Answer 26

autoimmune

alloimmune

Question 27

define autoimmune haemolysis

Answer 27

antibodies are made against own RBCs

Question 28

define alloimmune hameolysis

Answer 28

antibodies are made against foreign RBCs

Question 29

how can autoimmune haemolysis be further categorised

Answer 29

warm - IgG

cold - IgM

Question 30

what are some causes of autoimmune haemolysis

Answer 30

idiopathic 
viral infection 
drugs 
lymphoproliferative disorders
autoimmune conditions

Question 31

what test is done for autoimmune haemolysis

Answer 31

direct anti-globulin test DAT

Question 32

How can alloimmune haemolysis be further categorised

Answer 32

immune response

passive transfer

Question 33

describe immune response in alloimmune haemolysis

Answer 33

immediate reaction with IgM - usually intravascular

delayed reaction with IgG - usually extravascular

Question 34

describe passive transfer in alloimmune haemolysis

Answer 34

example - pregnancy

haemolytic disease of the newborn

Question 35

list mechanical causes of haemolysis

Answer 35

DIC 
HUS
TTP 
mechanical heart valve (MAHA)
infections: malaria

Question 36

what is a congenital cause of red cell membrane defect

Answer 36

hereditary spherocytosis

leads to extravascular haemolysis

Question 37

what are acquired causes of red cell membrane defects

Answer 37

Vitamin E deficiency
Liver disease - Zieve’s syndrome
Paroxysmal nocturnal haemoglobinuria - acquired molecular defect

Question 38

congenital cause of red cell metabolism defect

Answer 38

G6PD deficiency

Question 39

acquired cause of red cell metabolism defect

Answer 39

dapsone treatment

Question 40

cause of abnormal Hb resulting in haemolysis

Answer 40

sickle cell disease

Question 41

what is hereditary spherocytosis

Answer 41

genetic condition with abnormalities of the protein in the red cell membrane resulting in a loss of the biconcave shape and decreased membrane ability to squeeze through small vessels

Question 42

complications of hereditary spherocytosis

Answer 42

splenomegaly

extravascular haemolysis - these cells are recognised as abnormal and need removal

Question 43

symptoms of hereditary spherocytosis

Answer 43

anaemia - pallor, fatigue
jaundice - extravascular haemolysis
splenomegaly and LUQ pain
black pigment gallstones

Question 44

spherocytes have a large/small RDW and high/low reticulocytes

Answer 44

large

high reticulocytes

Question 45

management of hereditary spherocytosis

Answer 45

folic acid supplements

blood transfusion if emergency