Haemolysis

Question 1

what is haemolysis

Answer 1

premature red cell destruction

Question 2

why are red blood cells susceptible to damage

Answer 2

biconcave shape
limited metabolic reserve
can’t generate new proteins once in circulation

Question 3

what is compensated haemolytic

Answer 3

increased red cell destruction compensated by increased red cell production i.e. Hb maintained

Question 4

what is hameolytic anaemia

Answer 4

decompensated haemolysis

increased rate of red cell destruction exceeding bone marrow capacity for red cell production i.e. Hb falls

Question 5

consequence of haemolysi

Answer 5

erythroid hyperplasia - increased bone marrow RC production

excess RC breakdown products e.g. billirubin

Question 6

what is the bone marrow response to haemolytic

Answer 6

reticulocytosis

erythroid hyperplasia

Question 7

reticulocytosis other causes

Answer 7

bleeding

iron therapy in iron defic anaemia

Question 8

stain for reticulocytes

Answer 8

supra vital stain staining ribosomal RNA

new methylene blue

Question 9

way of counting reticulocytes

Answer 9

automated reticulocyte counting

Question 10

classification of haemolytic

Answer 10

extravascular - taken up by reticuloendothelial system (spleen and liver predom)

intravascular - red cells destroyed within the circulation

Question 11

extravascular red cell destruction

Answer 11

commoner
hyperplasia at site of destruction
release of protoporphyrin - unconjugated bilirubin - jaundice/gall stones. urobilinogenuria

normal products

Question 12

intravascular red cell destruction

Answer 12

red cells destroyed in circulation spilling their contents

haemaglobinaemia
methaemalbuminaemia
haemaglobinuria: pink urine turns black on standing
haemosiderinuria

Question 13

what type of haemolysis can be life threatening

Answer 13

intravascular

Question 14

causes of intravascular

Answer 14

ABO incompatible blood transfusion
G6PD defic
severe falciparum malaria (blackwater fever)

Question 15

causes of extravascular

Answer 15

all other causes of haemolysis

Question 16

ix confirm haemolytic state

Answer 16

confirm haemolytic state
FBC plus film
reticulocyte count
serum unconj bili
serum haptoglobin
urinary bili

Question 17

ix identify cause

Answer 17

history and exam
blood film: membrane damage (spherocytes), mechanical damage (red cell fragments), oxidative damage (heinz bodies), HbS (sickle cells)

Question 18

site of red cell defect classification

Answer 18

premature destruction of normal red cells (immune or mechanical)

abnormal cell membrane

abnormal red cell metabolism

abnormal Hb

Question 19

immune haemolysis

Answer 19

AI haemolysis

Alloimmune haemolysis

Question 20

AIH types

Answer 20

warm (IgG):
idiopathic. commonest 
AI disorders (SLE)
lymphocytic disorders 
drugs (penicillin etc)
infections 

cold (IgM):
idiopathic
infection (EBV, mycoplasma)
lymphoproliferative disorders

Question 21

what is the direct coombs test

Answer 21

identifies AB (and complement) bound to own red cells

Question 22

Alloimmune haemolysis

Answer 22

immune response (AB produced):
haemolytic transfusion reaction - immediate IgM predom intravas or delayed IgG extra

passive transfer of antibody:
haemolytic disease of the newborn - RH D, ABO incompatibility, anti Kell

Question 23

mechanical red cell destruction

Answer 23

DIC
haemolytic uraemic synd (E Coli 0157)
TTP
leaking heart valve
infection e.g. malaria

Question 24

mechanical valve related

Answer 24

microangiopathic haemolytic anaemia MAHA

Question 25

burns related haemolysis

Answer 25

microspherocytes red cell are sheared as they pass through the damages capillaries severe burns

Question 26

membrane defects acquired

Answer 26

liver disease - zieves synd Vit E defic Paroxysmal nocturnal Haemoglobinuria

Question 27

Zieves syndrome

Answer 27

haemolysis alcoholic liver dx hyperlipidaemia anaemia, polychromatic macrocytes, irregularly contracted cells

Question 28

paroxysmal nocturnal Hb

Answer 28

film ham's test marrow acquired molecular defect - rare

Question 29

membran defects congenital

Answer 29

hereditary spherocytosis

Question 30

abnormal red cell metabolism congenital

Answer 30

GP6D defic - failure to cope with oxidant stress

Question 31

what does dapsone cause in px w Gp6D defic features

Answer 31

haemolytic anaemia keratocyte and irregularly contracted cell Heinz bodies

Question 32

abnormal Hb congenital

Answer 32

Sickle cell dx