EMZYMOPATHIES AND MEMBRANOPATHIES

Question 1

What is the structure of the red cell? A biconcave disc

Answer 1

allowing flexibility and efficient navigation in narrow capillaries.

Question 2

Why is red cell metabolism important? It generates ATP (via anaerobic glycolysis) to maintain shape

Answer 2

volume

Question 3

What are the key enzymes in red cell metabolism? Glucose-6-phosphate dehydrogenase (G6PD) and pyruvate kinase.

Question 4

What is the role of G6PD in red cells? It reduces NADP to NADPH

Answer 4

which keeps glutathione in its reduced form to prevent oxidative injury.

Question 5

What is the most common cause of red cell membrane disorders? Defects in cytoskeletal proteins like spectrin

Answer 5

ankyrin

Question 6

What is the pathophysiology of spherocytosis? Deficiency or structural defects in spectrin reduce surface-to-volume ratio

Answer 6

creating less flexible spherical red cells prone to extravascular hemolysis.

Question 7

What is the pathophysiology of elliptocytosis? Mutations in spectrin disrupt the cytoskeletal lattice

Answer 7

resulting in elliptical-shaped red cells prone to hemolysis.

Question 8

What are clinical features of red cell membrane disorders? Anemia

Answer 8

jaundice

Question 9

How is hereditary spherocytosis diagnosed? Reduced fluorescence in eosin-5-maleimide staining

Answer 9

spectrin deficiency on electrophoresis

Question 10

What is the treatment for hereditary spherocytosis? Folic acid supplementation

Answer 10

splenectomy for severe cases

Question 11

What triggers hemolysis in G6PD deficiency? Oxidative stress from infections

Answer 11

drugs (e.g.

Question 12

What are the clinical syndromes in G6PD deficiency? Acute hemolytic anemia

Answer 12

neonatal jaundice

Question 13

What are Heinz bodies? Aggregates of denatured hemoglobin

Answer 13

visible with special stains

Question 14

What are key findings in G6PD deficiency during a hemolytic episode? Anemia

Answer 14

bite cells

Question 15

How is G6PD deficiency diagnosed? Enzyme assay

Answer 15

although levels may be falsely normal during a hemolytic crisis; repeat testing later is advised.

Question 16

What is the inheritance pattern of G6PD deficiency? X-linked recessive.

Question 17

What is pyruvate kinase (PK) deficiency? An autosomal recessive enzyme defect causing impaired ATP production and rigid red cells

Answer 17

leading to extravascular hemolysis.

Question 18

What are clinical features of PK deficiency? Milder anemia than G6PD deficiency

Answer 18

splenomegaly

Question 19

What is the treatment for PK deficiency? Folic acid supplementation

Answer 19

transfusions if needed

Question 20

What complications are common in red cell enzymopathies? Iron overload

Answer 20

gallstones

Question 21

What is unconjugated hyperbilirubinemia? An increase in unconjugated bilirubin due to excessive hemolysis

Answer 21

leading to jaundice.

Question 22

What are gallstones in hemolytic anemia composed of? Pigmented bilirubin stones due to chronic hemolysis.

Question 23

What is the conclusion about membrane and enzyme disorders? These inheritable intracorpuscular defects cause hemolytic anemia

Answer 23

with membrane defects causing extravascular hemolysis and enzyme defects causing mixed hemolysis.