Haemolysis Flashcards
Why are red cells susceptible to damage?
Biconcave shape
Limited metabolic reserve and rely on glycolysis
Cant generate new proteins
What are the characteristics of compensated haemolysis?
Increased red cell destruction compensated by increased red cell production
Haemoglobin maintained
What are the characteristic of decompensated haemolysis?
Increased rate of red cell destruction
Exceeding capacity for red cell production
Hb falls
What are the consequences of haemolysis?
Erythroid hyperplasia
Excess red cell breakdown
What are the bone marrow responses to haemolysis?
Reticulocytosis
Erythroid hyperplasia
Are reticulocytes nucleated?
No
What do reticulocytes show?
Response to bleeding
Response to iron therapy
What stain shows reticulocytes?
New methylene blue stains ribosomal RNA
What is extravascular haemolysis?
Taken up by reticuloendothelial system by liver and spleen
What is intravascular haemolysis?
Red cells destroyed within the circulation
WHat is commoner Extravascular or intravascular haemolysis?
Extra
What is seen in extravascular haemolysis?
Hyperplasia at destruction site (splenomegaly, hepatomealy)
Release of protoporphyrin
What is seen due to release of protoporphyrin?
Unconjugated bilirubinaemia Jaundice Gall stones Urobilinogenuria Normal products in excess
What is seen in intravascular haemolysis?
Haemoglobinaemia Methaemalbuminaemia Haemoglobulinuria Haemosiderinuria Abnormal products LIFE THREATENING
Which is life threatening Extra or intravascular haemolysis?
Intravascular
What can cause intravascular haemolysis?
ABO incompatibility
G6PD deficiency
Severe falciparum malaria
PNH PCH
What investigations are doen for haemolysis?
Confrim haemolytic state -FBC -Reticulocute count -Serum Unconjugated bilirubin -Serum haptoglobins -Urinary urobilinogen Identify cause: -History and examination Blood film Coombs test
What are 4 sites of red cell defect?
Premature destruction of normal red cells
Abnormal cell membrane
Abnormal red cell metabolism
Abnormal haemoglobin
What are causes of IgG autoimmune haemolysis?
Idiopathic Autoimmune disorders Lymphoproliferative disorders Drugs Infections
What are causes of IgM autoimmune haemolysis?
Idiopathic
Infections
lymphoproliferative disorders
What is the purpose of direct coombs test?
Identify antibody bound to own red cells
patients red cells with anti-human IgG
What are causes of alloimmune haemolysis?
Immune response
Passive transfer of antibody
What is an example of immune response in alloimmune haemolysis?
Haemolytic transfusion reaction
Immediate IgM intravascular
Delayed igG extravascular
What is an example of Passive transfer of antibody?
Haemolytic disease of the newborn
RhD
ABO incompatibility
