Haemolysis Flashcards
What is haemolysis?
Premature death of red cells
What are the different causes of haemolysis?
Immune- autoimmune and alloimmune
Mechanical red cell destruction
Membrane defects
Abnormal red cell metabolism
Abnormal haemoglobin
Explain the immune causes of haemolysis
Autoimmune-
Cold (IgM)- idiopathic, infective, or lymphoproliferative causes
Warm (IgG)- idiopathic, infective, autoimmune conditions, or drug related causes
Alloimmune-
Transfusion Reactions:
Immediate- IgM, intravascular
Delayed- IgG, extravascular
Name some causes of mechanical red cell destruction
Disseminated intravascular coagulation
Haemolytic uraemic syndrome (haemolytic anaemia, thrombocytopenia, AKI)
TTP
Leaking heart valve
Infections like malaria
Burns related
Name some causes of membrane defects
Liver diseases like zieve syndrome
Vitamin E deficiency
Paroxysmal noctural haemoglobinuria
Hereditary spherocytosis
Name some causes of abnormal red cell metabolism
G6PD deficiency
Failure to generate ATP
Name some causes of abnormal haemoglobin
Sickle cell disease
Why are red cells susceptible to destruction?
Shape
No mitochondria- limited metabolic reserve
No nucleus so can’t regenerate proteins
What are the types of haemolysis?
Compensated- Hb maintained due to increased red cell production, in response to increased destruction
Decompensated/haemolytic anaemia- Hb falls due to exceeded bone marrow capacity for production
How is haemolysis classified?
Extravascular-
Red cells taken up by reticuloendothelial system (spleen and liver)- normal process but happens in excess
Causes hyperplasia at destruction site hence leading to hepatosplenomegaly
Releases protoporphyrin -> jaundice
Intravascular-
Red cells destroyed within circulation, releases free Hb into blood
Haemoglobinuria, Haemosiderinuria, Methaemalbuminaemia
Abnormal products
What is the bone marrow response to haemolysis
Reticulocytosis
Erythoid hyperplasia
How does haemolysis present?
Depends on cause and type
General anaemia symptoms, hepatosplenomegaly
Investigations for haemolytic anaemia
Blood test- check for LDH and bilirubin
Blood film- increased reticulocytes and spherocytosis, Heinz bodies (G6PD), red cell fragments
Direct Coombs test- identifies autoantibodies bound to red cells
How is haemolysis managed?
1mg/kg steroids + folic acid daily
Immunosuppression
Splenectomy
