G6PD Flashcards
Definition?
What kind of disease?
What does it cause?
X linked recessive (mostly men) enzymopathy
Due to decreased glucose-6-phosphate dehydrogenase =destruction of RBC
How is defective G6PD enzymes different to normal enzymes?
Shorter half life - doesn’t last as long
Pathology
What is G6PD used for?
Metabolic processes produce free radicals (eg. H2O2)
Free radicals damage cells by destroying DNA, proteins and cell membranes
Glutathione (anti oxidant) - neutralizes free radicals (H2O2 to H2O)
G6PD involved in glutathione synthesis
Defective G6PD enzymes = low glutathione = lots of free radicals = high RBC damage by haemolysis
Symptoms
Mostly asymptomatic unless precipitated/triggered
(Due to high free radicals production)
Causes that trigger symptoms
Food & drinks = fava beans, soy products & red wine
Anti malarials = quinine
Meds = aspirin, ibuprofen
Nitrofurantoin
What type of haemolysis do RBCs undergo in G6PD anemia?
Intravascular
When an attack is taking place, what symptoms occur?
Rapid anemia + Jaundice
What causes jaundice to occur?
Pathology
Hb = Globin + Heme
Heme —> bilirubin—> taken up by liver cells —> secreted in bile (normally)
Haemolysis = excess bilirubin
—> stay in blood = jaundice (bilirubin deposits in skin/eyes)
—> urobilin = urine (tea like colour)
Diagnosis?
Tests?
FBC + blood film
Normal in between attacks
Attack = normocytic normochromic with high reticulocytes
Heinz bodies + bite cells
Why do you see Heinz bodies?
Free radicals directly damage Hb (carry O2) , these proteins precipitate inside RBC
Why do we see bite cells?
Splenic macrophages try remove them by eating them
Treatment?
Avoid precipitants/triggers
Blood transfusion when attack occurs
Where is this disease most common and why is it good for that particular region?
Africa + Asia
Protect against malaria
