Quiz 6 Flashcards
(30 cards)
What causes a-thalassemia and what does it produce
Caused by mutated a-globin gene producing an excess of B-globin chains
Which form of thalassemia is less damaging
Excess b-globin is less damaging than excessive a globin (therefore a thalassemia is less damaging)
A-thalassemia has abnormal Hb (HbH) causing what?
Slight decrease in O2 capacity and ineffective erythropoiesis
Why is a-thalassemia highly variable
Determined by # of altered genes (4 a-globin genes)
Severity of a thalassemia is determined by what
of a-globin gene deletions
1 deletion of a globin gene produces what
Asymptomatic “silent carrier”
4 deletions of a-globin deletions produces what
No O2 capacity, lethal hydrops fetalis
What is glutathione and what does it do
It is an antioxidant. That protects RBC’s against oxidative stress (hemolysis)
What is needed to make glutathione (GSH)
Glucose 6 phosphate dehydrogenase (G6PD)
G6PD deficiency produces what?
A decrease in glutathione antioxidant (GSH)
Why is G6PD deficiency a problem
Older RBC’s at risk for damage/hemolysis
Who usually is affected by G6PD deficiency
X linked (males)
What is the most common G6PD
Infections
What can also cause G6PD
Fava beans (favism), and ADRS (antimalarial, antibiotics for ecoli UTI)
G6PD is _____ until exposed
Asymptomatic
With G6PD what are bite cells
Splenic phagocytosis from oxidation
G6PD can produce bite cells or ___
Heinz bodies
What happens 2-3 days after G6PD exposure
Hemolysis
What are some G6PD symptoms
Acute onset, fatigue, pallor, splenomegaly, back/abdominal pain, hemosiderinuria
What are risks for G6PD
Males (xlinked), African descent, areas of endemic malaria
What causes paroxysmal nocturnal hemoglobinuria
Acquired PIGA gene mutation on X chromosome (can affect females though)
What does a PIGA mutation deactivate
Deactivates complement inhibitors
When is paroxysmal nocturnal hemoglobinuria accelerated and why
Accelerated when sleeping, decrease in respiration = decrease in pH producing complement mediated hemolysis
What is there an increased risk for in those with PNH
Increased risk for venous thrombosis
