hemolysis

Question 1

what is hemolysis?

Answer 1

premature red cell destruction

Question 2

why are red cells particularly susceptible to damage? (3)

Answer 2

biconcave shape
limited metabolic reserve - no mitochondria
no nucleus (no new proteins)

Question 3

what metabolism do red cells depend on?

Answer 3

glucose metabolism

Question 4

what is compensated hemolysis?

Answer 4

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

Question 5

what is most commonly seen?

Answer 5

haemolytic anaemia

Question 6

what is hemolytic anaemia?

Answer 6

increased rate of red cell destruction exceeding bone marrow capacity for red cell production - Hb falls

Question 7

what are the consequences of hemolysis? (2)

Answer 7

erythroid hyperplasia

excess red cell breakdown products eg. bilirubin

Question 8

bone marrow response to haemolysis?

Answer 8

reticulocytosis

erythroid hyperplasia

Question 9

what stains reticulocyte ribosomal RNA?

Answer 9

new methylene blue

Question 10

what is extravascular hemolytic anaemia?

Answer 10

taken up by reticuloendothelial system (spleen and liver predominantly)

Question 11

what is intravascular hemolytic anaemia?

Answer 11

red cells destroyed within the circulation

Question 12

what is the common form of hemolytic anaemia?

Answer 12

extravascular

Question 13

chronic extravascular hemolytic anaemia may present with?

Answer 13

splenomegaly +/- hepatomegaly

Question 14

what type of. products are released in extravascular red cell destruction?

Answer 14

normal products in excess

Question 15

what products are released in extravascular red cell destruction?

Answer 15

unconjugated bilirubinaemia

urobilinogenuria

Question 16

what is the presentation of unconjugated bilirubinaemia?

Answer 16

jaundice and gall stones

Question 17

what is intravascular red cell destruction?

Answer 17

red cells are destroyed in the circulation spilling their contents

Question 18

what products are released in intravascular red cell destruction?

Answer 18

haemoglobinaemia
methaemalbuniaemia
haemolgobinuria
haemosiderinuria

Question 19

what happens to hemoglobinuria?

Answer 19

pink urine turns black on oxidation

Question 20

what type of products are released in intravascular red cell destruction?

Answer 20

abnormal products

Question 21

which type of haemolysis is life threatening?

Answer 21

intravascular

Question 22

what conditions cause intravascular hemolysis? (4)

Answer 22

ABO incompatible blood transfusion
G6PD deficiency
Severe falciparum malaria (Blackwater Fever)
Rarer still PNH,PCH

Question 23

what is the most common red cell enzyme deficiency?

Answer 23

G6PD deficiency

Question 24

what conditions cause extravascular hemolysis?

Answer 24

essentially all other causes of hemolysis

Question 25

what investigations confirm hemolytic state? (5)

Answer 25

``` FBC (+ BLOOD FILM) Reticulocyte count Serum unconjugated bilirubin Serum haptoglobins Urinary urobilinogen ```

Question 26

what excludes someone haemolysing?

Answer 26

FBC and blood film

Question 27

what do you see on the blood film if red cell membranes are damaged?

Answer 27

spherocytes

Question 28

what do you see on the blood film if there is oxidative damage?

Answer 28

Heinz bodies

Question 29

what do you see on the blood film If there is mechanical damage?

Answer 29

red cell fragments

Question 30

what is a specialist investigation for hemolysis?

Answer 30

direct coombs' test and others

Question 31

what is the most common cause of premature destruction of normal red cells?

Answer 31

autoimmune, or mechanical | valve disease

Question 32

autoimmune hemolysis?

Answer 32

antibodies developed to own red cell

Question 33

what is alloimmune hemolysis?

Answer 33

antibodies developed to foreign red cells

Question 34

what are warm autoantibodies?

Answer 34

IgG

Question 35

what are cold autoantibodies?

Answer 35

IgM

Question 36

what is the commonest cause of warm autoimmune hemolysis?

Answer 36

idiopathic

Question 37

what are other warm autoimmune hemolysis?

Answer 37

``` Idiopathic (commonest) Autoimmune disorders (SLE) Lymphoproliferative disorders (CLL) Drugs (penicillins, etc) - high doses given IM Infections ```

Question 38

what are causes of cold autoimmune hemolysis?

Answer 38

idiopathic infections (EBV, mycoplasma) Lymphoproliferative

Question 39

what is the commonest form of autoimmune hemolysis?

Answer 39

warm (IgG) hemolysis

Question 40

what is the purpose of direct coombs' test?

Answer 40

identifies antibody (and complement) bound to own red cells

Question 41

alloimmune hemolysis can be?

Answer 41

``` immune response (antibodies produced) passive transfer of antibody ```

Question 42

what is an example of alloimmune immune response hemolysis?

Answer 42

hemolyticc transfusion reaction

Question 43

how can you differentially if the HTR is predominantly intravascular or extravascular?

Answer 43

Immediate IgM - intravascular | delayed IgG - extravascular

Question 44

what are examples of passive transfer of antibody in alloimmune hamemolysiss?

Answer 44

hemolytic disease of the newborn

Question 45

what are causes of acquired haemolysis - mechanical red cell destruction?

Answer 45

``` Disseminated intravascular coagulation Haemolytic uraemic syndrome (eg E. coli O157) TTP Leaking heart valve Infections e.g. Malaria ```

Question 46

what are examples of membrane defects?

Answer 46

``` Liver Disease (Zieve’s Syndrome) Vitamin E deficiency Paroxysmal Nocturnal Haemoglobinuria ```

Question 47

what is a genetic cause of red cell membrane abnormalities?

Answer 47

hereditary spherocytosis

Question 48

people with normal levels of G6PD are also under

Answer 48

oxidative stress then they are on dapsone therapy

Question 49

what is an example of abnormal hemoglobin?

Answer 49

sickle cell disease

Question 50

what is affected in sickle cell disease>

Answer 50

physical properties of haemoglobin (abnormal polymerisation) resulting in shortened red cell survival

Question 51

where is the mutation in sickle cell disease?

Answer 51

caused by a point mutation in beta globin chain

Question 52

why isn't the presence of spherocytes diagnostic in hereditary spherocytosis?

Answer 52

it can be seen in severe burns | immune hemolytic anaemias