Red Cell Survival Flashcards
How much red blood cells are in the adult human body?
5.5 x 10(12) /L red cells
Where is each red cell synthesised and how long does it survive in circulation for?
Synthesised in the bone marrow
120 days
What does red cells contain and why?
Contain haemoglobin
Binds oxygen and delivers it to tissues to aid oxidative phosphorylation in cells
What is haemolytic anaemia?
If the rate of destruction of red cells is greater than the production
What are immature red cells called?
Reticulocytes
What do immature red cells contain?
Remnants of mRNA
What does it mean when an individual is given penicillin G and suffers a rash with decreasing levels after 15 days?
Second exposure = haemolytic response
Confirmed by increase in reticulocytes
What is a direct antiglobulin test (DAT)?
AKA direct Coombs test
adding anti-lgG to detect lgG that is attached to the RBCs
also detects C3 complement fragments on the RBC surface
Why does the antibody bind to the red cell?
antibody’s (IgG) and memory cells are synthesised
Antibody increases in the plasma and binds to penicillin coated red cells
What happens once the coated cells have an antibody bonded to them?
Red cells are engulfed by macrophages
OR binds complement which leads to lysis of the red cells
How does bone marrow respond?
Increases the rate of red cell production and releases reticulocytes into the circulation
What is the treatment for this?
Stop penicillin treatment
Administer steroids to suppress the immune system
Plasmapheresis and blood transfusion
What is dapsone?
An antibacterial agent used for treating mycobacterium tuberculosis
What cause dapsone cause?
Oxidation of haemoglobin to a form called methaemoglobin (if not corrected this is non functional haemoglobin)
How are Heinz bodies formed?
Dapsone induced denaturalising of methaemoglobin
