CBL Long Case 1 - Anaemia

Question 1

Define haemolysis [1]

Answer 1

increase in red cell destruction

Question 2

What are the 2 mechanisms of RBC destruction in haemolytic anaemias? [2]

Answer 2

1. intravascular
   
   • destruction of RBCs occurring directly in the circulation
2. extravascular
   
   • destruction of RBCs within the RES system of the spleen, liver and bone marrow

Question 3

What are the causes of intravascular haemolysis? [4]

Answer 3

1. mechanical trauma to the RBC
2. can occur after an ABO incompatible blood transfusion
3. malaria
4. cold (IgM) autoantibodies

Question 4

What are the causes of cold autoimmune haemolytic anaemia? [4]

Answer 4

1. primary (idiopathic)
2. secondary…
   
   • infection by mycoplasma pneumoniae
   • infectious mononucleosis (glandular fever)
   • lymphoproliferative disorders

Question 5

What are the typical laboratory findings in intravascular haemolysis? [6]

Answer 5

1. anaemia
2. reticulocytosis
3. raised unconjugated bilirubin
4. haemoglobinaemia
5. haemoglobinuria
6. haemosiderinuria

Question 6

Describe the pathogenesis of extravascular haemolysis [4]

Answer 6

1. extravascular haemolysis is related to the production of “warm” (incomplete) antibodies, usually IgG
2. IgG attaches to the red cell antigen and damages the RBC membrane
3. the damaged RBCs become spherocytic and are phagocytosed by the RES, particularly in the spleen, resulting in the spleen to be enlarged

Question 7

What are the causes of warm type autoimmune haemolytic anaemia (AIHA)? [8]

Answer 7

1. primary (idiopathic)
2. secondary causes:
   
   • lymphoproliferative disorders such as:
     
     • chronic lymphocytic leukaemia
     • non-Hodgkin’s lymphoma
   • other neoplasms
   • systemic lupus (SLE) and other connective tissue disorders
   • drugs

Question 8

What are the management options for acquired warm type haemolytic anaemia? [4]

Answer 8

1. corticosteroids
   
   • high dose prednisolone
2. blood transfusion
3. folic acid
4. splenectomy