G6PD Deficiency
What is the biochemical consequence of G6PD deficiency? - Answer G6PD is an
enzyme in the hexose monophosphate shunt that helps reduce oxidized species
generated as part of RBC metabolism. Without reductive capacity, hydrogen peroxide
accumulates within RBCs, which damages lipids in the RBC membrane, leading to
hemolysis.
Why is hemolysis not a common problem in these patients? - Answer These patients
are usually heterozygotes, so, on average, their RBCs contain 50% of the normal
enzyme level. Under normal conditions, these cells can handle routine oxidative
stresses, but in circumstances of greatly increased stress, such as infections or certain
drug exposures, oxidation leads to hemolysis.
What conditions can precipitate hemolytic episodes in patients with G6PD deficiency? -
Answer Medications are most common (e.g., anticonvulsants, phenazopyridine,
phenylhydrazine, and sulfa drugs); fever, infection, and certain foods (e.g. fava beans)
How is the diagnosis of G6PD deficiency made? - Answer RBC G6PD levels can be
measured.
What is the pathognomonic finding on blood smear? - Answer HEINZ BODIES and
BITE CELLS on smear
What is important about the timing in measuring the G6PD level? - Answer The level
should not be measured during or shortly after a hemolytic episode because the older
RBCs containing decreased amounts of G6PD will have lysed, leaving only the younger
cells containing higher levels of G6PD.
What is the biochemical consequence of G6PD deficiency? - Answer G6PD is an
enzyme in the hexose monophosphate shunt that helps reduce oxidized species
generated as part of RBC metabolism. Without reductive capacity, hydrogen peroxide
accumulates within RBCs, which damages lipids in the RBC membrane, leading to
hemolysis.
Why is hemolysis not a common problem in these patients? - Answer These patients
are usually heterozygotes, so, on average, their RBCs contain 50% of the normal
enzyme level. Under normal conditions, these cells can handle routine oxidative
stresses, but in circumstances of greatly increased stress, such as infections or certain
drug exposures, oxidation leads to hemolysis.
What conditions can precipitate hemolytic episodes in patients with G6PD deficiency? -
Answer Medications are most common (e.g., anticonvulsants, phenazopyridine,
phenylhydrazine, and sulfa drugs); fever, infection, and certain foods (e.g. fava beans)
How is the diagnosis of G6PD deficiency made? - Answer RBC G6PD levels can be
measured.
What is the pathognomonic finding on blood smear? - Answer HEINZ BODIES and
BITE CELLS on smear
What is important about the timing in measuring the G6PD level? - Answer The level
should not be measured during or shortly after a hemolytic episode because the older
RBCs containing decreased amounts of G6PD will have lysed, leaving only the younger
cells containing higher levels of G6PD.
