Haemolysis

Question 1

what is haemolysis?

Answer 1

premature destruction of red cells

Question 2

why does bilirubin increase in haemolysis?

Answer 2

RBC breakdown breaks haemoglobin into its constituent parts

porphyrin ring breakdown eventually forms bilirubin

Question 3

why are red cells susceptible to damage?

Answer 3

no nucleus - cant generate new proteins
limited metabolic reserve - rely on glycolysis
biconcave shape

Question 4

what are Hb levels like in compensated haemolysis and why?

Answer 4

normal

haemolysis is compensated by inc RBC production

Question 5

another term for decompensated haemolysis?

Answer 5

haemolytic anaemia

Question 6

what is Hb like in haemolytic anaemia and why?

Answer 6

low

inc rate of haemolysis exceeds BM’s capacity for RBC production

Question 7

what does the bone marrow do in response to haemolysis?

Answer 7

undergoes erythroid hyperplasia (inc BM red cell production) to produce more reticulocytes

Question 8

what can you measure to look for haemolysis?

Answer 8

reticulocytes

breakdown products eg bilirubin

Question 9

reticulocytosis is diagnostic of haemolysis T or F

Answer 9

F

present in bleeding, iron therapy etc

Question 10

what cells are polychromatic and why?

Answer 10

reticulocytes

contain RNA

Question 11

where is the main site of destruction in extravascular haemolysis

Answer 11

liver and spleen

Question 12

where is the main site of destruction in intravascular haemolysis?

Answer 12

circulation

Question 13

is extravascular or intravascular haemolysis more common?

Answer 13

extravascular

Question 14

what happens to the organs at the site of destruction in extravascular haemolysis?

Answer 14

undergo hyperplasia

eg splenomegaly

Question 15

what does the release of protoporphyrin in extravascular haemolysis cause?

Answer 15

unconj bilirubinaemia
jaundice
gallstones
urobilinogenuria

Question 16

what haemolysis type is controlled and therefore does NOT have abnormal breakdown products?

Answer 16

extravascular haemolysis

Question 17

pathophysiology of intravascular haemolysis?

Answer 17

red cells spill their contents into the bloodstream
free Hb in blood and urine
Hb breakdown products combine with other substances to form toxic products in blood and urine

Question 18

colour of urine in haemoglobinuria?

Answer 18

pink, turns black on standing

Question 19

what is the cause methaemalbuminaemia?

Answer 19

Hb breakdown product methaem forms a complex with albumin in the blood

Question 20

causes of intravascular haemolysis?

Answer 20

ABO incompatible blood transfusion
G6PD dfeficiency
malaria

Question 21

Ix haemolysis

Answer 21

FBC
blood film
reticulocyte count
serum unconj bilirubin
serum haptoglobins
urinary urobilinogen

Question 22

what should urine be checked for in haemolysis?

Answer 22

urobilinogen

Question 23

unconjugated or conjugated bilirubin increases in haemolysis?

Answer 23

unconjugated

Question 24

why is haptoglobin checked?

Answer 24

haptoglobin binds prehaemoglobin so if Hb is low from haemolysis this will also be low

Question 25

genetic causes of haemolysis

Answer 25

haemoglobinopathies G6PD deficiency thalassaemia sickle cell (look for HbS)

Question 26

spherocytes indicate...

Answer 26

membrane damage

Question 27

heinz bodies indicate..

Answer 27

oxidative damage

Question 28

what factors can lead a red cell to haemolyse?

Answer 28

premature destruction dysfunctional cell membrane abnormal metabolism abnormal Hb

Question 29

most common form of autoimmune haemolysis?

Answer 29

warm autoimmune haemolytic anaemia

Question 30

what antibody is involved in warm autoimmune HA?

Answer 30

IgG

Question 31

what antibody is involved in cold autoimmune HA?

Answer 31

IgM

Question 32

causes of warm autoimmune HA?

Answer 32

``` idiopathic autoimmune disorder eg SLE chronic lymphocytic leukaemia drugs eg penicillins infection ```

Question 33

causes of cold autoimmune HA?

Answer 33

idiopathic infections eg EBV/mycoplasma lymphoproliferative disorders

Question 34

what happens in a direct coombs test?

Answer 34

given antibodies to see if they bind to your own red cells (which causes agglutination)

Question 35

pathophysiology of autoimmune HA?

Answer 35

producing antibodies against your own RBC antigens

Question 36

causes of alloimmune haemolysis?

Answer 36

transfusion reaction | haemolytic disease of newborn due to rhesus/ABO cause

Question 37

if a transfusion reaction IMMEDIATELY causes haemolysis, what kind of haemolysis will it be and what antibody will cause it?

Answer 37

IgM | intravascular haemolysis

Question 38

if a transfusion reaction causes a DELAYED haemolysis, what kind of haemolysis will it be and what antibody will cause it?

Answer 38

IgG | extravascular

Question 39

causes of acquired haemolysis from MECHANICAL destruction?

Answer 39

coagulation disorder HUS (e.coli 0157) leaky heart valve infections eg malaria

Question 40

microspherocytes are a sign of..

Answer 40

burns related haemolysis (sheared as they pass through damaged capillaries)

Question 41

name the triad of symptoms for zieve's syndrome

Answer 41

haemolysis alcoholic liver disease hyperlipidaemia

Question 42

G6PD deficiency most often affects which members of the population?

Answer 42

MALES

Question 43

consequences of G6PD deficiency?

Answer 43

cant generate ATP | cant cope with oxidant stess

Question 44

bony deformities, chronic anaemia and erythroid hyperplasia...

Answer 44

beta thal major

Question 45

what is alloimmunity?

Answer 45

immune response to a foreign antigen

Question 46

parent had splenectomy, child has splenomegaly...

Answer 46

hereditary spherocytosis