9. Introduction to Hemolytic Anemias: Intracorpuscular Defects: I. Hereditary Defects of the Red Cell Membrane

Question 1

1.What happens when normal donor red cells are transfused into a patient with an intracorpuscular red cell defect?

a. Donor cells are destroyed.
b. Donor cells have normal survival.
c. Depends on the severity of the defect.
d. Depends on the severity of the anemia.

Answer 1

b. Donor cells have normal survival.

Question 2

2. Which of the following tests is not used to determine increased red cell destruction?

a. Unconjugated (indirect) bilirubin
b.Serum haptoglobin
c.Schumm’s test
d.Reticulocyte count

Answer 2

d.Reticulocyte count

Question 3

3.An anemic patient investigated for a hemolytic state has the following laboratory findings: hemoglobin, 8 g/dL; hematocrit, 23%; reticulocyte count, 8%; polymorphs on peripheral smear. What is the RPI?

a.8
b.4
c. 2
d. 1

Answer 3

c. 2

Question 4

4. What tests are useful in the classification of the cause of red cell hemolysis?

a.Coombs test
b.Hemoglobin level and electrophoresis
c.Reticulocyte count
d. Red cell enzyme studies and iron-binding capacity

Answer 4

a.Coombs test

Question 5

5.Which of the following red cell membrane protein defi-ciencies does not cause hereditary spherocytosis?

a.Ankyrin
b. Protein 4.1
c. Protein 4.2
d. Band 3

Answer 5

b. Protein 4.1

Question 6

6.Which of the following laboratory tests would not be typical of hereditary spherocytosis?

a. Increased osmotic fragility
b. spherocytes on peripheral smear
c. Decreased MCHC
d. Increased RPI

Answer 6

c. Decreased MCHC

Question 7

7.Which is the most frequent functional abnormality affecting membrane skeleton proteins in common hereditary elliptocytosis?

a. Defective binding of spectrin to ankyrin
b. Defective spectrin tetramer assembly
c. Defective binding of ankyrin to protein 3
d. Deficiency of protein 4.1

Answer 7

b. Defective spectrin tetramer assembly

Question 8

8.Which of the following abnormalities is (are) thought to cause the severe fragmentation and microspherocytes characteristic of hereditary pyropoikilocytosis ?

a. Susceptibility of spectrin to thermal denaturation
b. Defective membrane spectrin tetramer assembly and spectrin deficiency
c. Unstable membrane lipids
d. Membrane ankyrin deficiency

Answer 8

b. Defective membrane spectrin tetramer assembly and spectrin deficiency

Question 9

9. Which of the following findings are not typical of South-east Asian ovalocytosis?

a. A deletion of nine amino acids in band 3
b. Resistance to infection by malaria parasite
c. A defiiency of band 3
d. Rigid spoon-shaped ovalocytes

Answer 9

c. A defiiency of band 3

Question 10

10. Which disorders are classified as disorders of membrane cation permeability?

a. Hereditary stomatocytosis and hereditary xerocytosis
b. Sideroblastic anemia and myelofibrosis
c. Autoimmune hemolytic anemia and microangiopathic hemolytic anemia
d. Ehlers-Danlos syndrome and Bernard-Soulier syn-drome

Answer 10

a. Hereditary stomatocytosis and hereditary xerocytosis