Haemolysis

Question 1

what is hameolysis?

Answer 1

premature red cell destruction

Question 2

what are the features of red blood cells that make them more susceptible to damage?

Answer 2

Biconcave shape
Limited metabolic reserve (no mitochondria)
Can’t generate new proteins once in the circulation (no nucleus)

Question 3

haemolysis can be…

Answer 3

compensated or decompensated

Question 4

what is compensated haemolysis?

Answer 4

Increased red cell destruction compensated by increased red cell production
= Hb Maintained

Question 5

what is decompensated haemolysis?

Answer 5

decompensated haemolysis

o Increased rate of red cell destruction exceeding bone marrow capacity for red cell production = Hb Falls

Question 6

what are the consequences of haemolysis?

Answer 6

o Erythroid hyperplasia (increased bone marrow red cell production)
o Excess red cell breakdown products eg bilirubin

Question 7

what is the bone marrow response to haemolysis?

Answer 7

1. Reticulocytotic

2. Erythroid hyperplasia

Question 8

how does reticulocytosis appear on blood film?

Answer 8

• Non nucleated

* polychromsia (ribosomal RNA)

Question 9

what are the different classifications of haemolysis?

Answer 9

Extravascular 
Intravascular
Premature destruction
Abnormal cell membrane
Abnormal Red Cell Metabolism 
Abnormal Haemoglobin

Question 10

where does extravascular haemolysis occur?

Answer 10

reticuloendothelial system (liver and spleen)

Question 11

what are the causes of extravascular haemolysis?

Answer 11

majority of causes of haemolysis?

Question 12

what are the blood products in extravascular haemolysis?

Answer 12

normal products in excess

Question 13

which forms of bilirubin are found in extravascular haemolysis?

Answer 13

• Unconjugated bilrubinaemia

* Urobilinogenuria

Question 14

where does intravascular haemolysis occur?

Answer 14

within the circulation

Question 15

what are the blood products in intravascular haemolysis?

Answer 15

abnormal

Question 16

what are the causes of intravascular haemolysis?

Answer 16

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

Question 17

the blood products in intravascular haemolysis are found as?

Answer 17

• Haemoglobinaemia (free Hb in circulation)
• Methaemalbuminaemia
• Haemoglobinuria:
• Haemosiderinuria

Question 18

premature destruction of normal red cells is an

Answer 18

acquired process

Question 19

premature destruction of red cells can be either:

Answer 19

immune or mechanical

Question 20

what are the two types of immune premature destruction of normal red cells?

Answer 20

Autoimmune and

Alloimmune Haemolysis

Question 21

what are the causes of warm autoimmune haemolysis?

Answer 21

o	Idiopathic (commonest)
o	Autoimmune disorders (SLE)
o	Lymphoproliferative disorders (CLL)
o	Drugs (penicillins, etc)
o	Infections

Question 22

what are the causes of cold autoimmune haemolysis?

Answer 22

o Idiopathic
o Infections (EBV, mycoplasma)
o Lymphoproliferative disorders

Question 23

what are the causes of immune response alloimmune haemolysis?

Answer 23

Haemolytic transfusion reaction
 Immediate (IgM) predominantly intravascular
 Delayed (IgG) predominantly extravascular

Question 24

what are the causes of passive transfer of antibody in alloimmune haemolysis?

Answer 24

Haemolytic disease of the newborn - Rh D, ABO incompatibility, Others eg anti-Kell

Question 25

what are the mechanical causes of Premature destruction of normal red cells?

Answer 25

Disseminated intravascular coagulation
Hemolytic uremic syndrome (eg E. coli O157)
TTP
Leaking heart valve (microangiopathic hemolytic anaemia)
Infections e.g. Malaria
Burns

Question 26

what are the acquired causes of haemolysis caused by abnormal cell membranes?

Answer 26

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

Question 27

what are the congenital causes of haemolysis caused by abnormal cell membranes?

Answer 27

• Reduced membrane deformability
• Increased transit time through spleen
• Oxidant environment in spleen causes extravascular red cell destruction
• Hereditary Spherocytosis

Question 28

what are the congenital causes of abnormal red cell metabolism leading to haemolysis?

Answer 28

• Reduced membrane deformability
• Increased transit time through spleen
• Oxidant environment in spleen causes extravascular red cell destruction
• Hereditary Spherocytosis

Question 29

what condition causes abnormal haemoglobin that can lead to haemolsyis?

Answer 29

Sickle Cell Disease

Question 30

what type of anaemia is haemolytic anaemia?

Answer 30

normocytic or macrocytic

Question 31

how can haemolytic anaemia be diagnosed?

Answer 31

1. Confirm Haemolytic State

2. Identify Cause

Question 32

how is the haemolytic state confirmed in haemolytic anaemia?

Answer 32

• FBC (+ Blood Film)
• Reticulocyte Count
• Serum unconjugated bilirubin
• Serum haptoglobins
• Urinary urobilinogen

Question 33

how is the cause of haemolytic anaemia identified?

Answer 33

• History and examination : Genetic/Acquired
• Blood Film
• Specialist investigations (Direct Coombs’ test and others)

Question 34

what are the features on blood film looked at in haemolytic anaemia?

Answer 34

o Membrane damage (spherocytes)
o Mechanical damage (red cell fragments)
o Oxidative damage (Heinz bodies)
o Others e.g.. HbS (sickle cells)