CHAPTER 21: ANEMIAS CAUSED BY DEFECTS OF DNA METABOLISM

Question 1

(1) Which of the following findings is consistent with a diagnosis of megaloblastic anemia?

a. Hyposegmentation of neutrophils
b. Decreased serum lactate dehydrogenase level
c. Absolute increase in reticulocytes
d. Increased MCV

Answer 1

d. Increased MCV

Question 2

(2) A patient has a clinical picture of megaloblastic anemia. The serum folate level is decreased, and the serum vitamin B12 level is 600 pg/mL (reference interval is 200–900 pg/mL). What is the expected value for the methylmalonic acid assay?

a. Increased
b. Decreased
c. Within the reference interval

Answer 2

c. Within the reference interval

Question 3

(3) Which one of the following statements characterizes the relationships among macrocytic anemia, megaloblastic anemia, and pernicious anemia?

a. Macrocytic anemias are megaloblastic.
b. Macrocytic anemia is pernicious anemia.
c. Megaloblastic anemia is macrocytic.
d. Megaloblastic anemia is pernicious anemia.

Answer 3

c. Megaloblastic anemia is macrocytic.

Question 4

(4) Which of the following CBC findings is most suggestive of a megaloblastic anemia?

a. MCV of 103 fL
b. Hypersegmentation of neutrophils
c. RDW of 16%
d. Hemoglobin concentration of 9.1 g/dL

Answer 4

b. Hypersegmentation of neutrophils

Question 5

(5) In the following description of a bone marrow smear, find the statement that is inconsistent with the expected picture in megaloblastic anemia. “The marrow appears hypercellular with a myeloid-to-erythroid ratio of 1:1 due to prominent erythroid hyperplasia. Megakaryocytes appear normal in number and appearance. The WBC elements appear larger than normal, with especially large metamyelocytes, although they otherwise appear morphologically normal. The RBC precursors also appear large. There is nuclear-cytoplasmic asynchrony, with the nucleus appearing more mature than expected for the color of the cytoplasm.”

a. Erythroid nuclei that are more mature than cytoplasm
b. Larger than normal WBC elements
c. Larger than normal RBCs
d. Normal appearance of megakaryocytes

Answer 5

a. Erythroid nuclei that are more mature than cytoplasm

Question 6

(6) Which one of the following findings would be inconsistent with elevated titers of intrinsic factor blocking antibodies?

a. Hypersegmentation of neutrophils
b. Low levels of methylmalonic acid
c. Macrocytic RBCs
d. Low levels of vitamin B12

Answer 6

b. Low levels of methylmalonic acid

Question 7

(7) Which of the following is the most metabolically active form of absorbed vitamin B12?

a. Transcobalamin
b. Intrinsic factor–vitamin B12 complex
c. Holotranscobalamin
d. Haptocorrin–vitamin B12 complex

Answer 7

c. Holotranscobalamin

Question 8

(8) Folate and vitamin B12 work together in the production of:

a. Amino acids
b. RNA
c. Phospholipids
d. DNA

Answer 8

d. DNA

Question 9

(9) The macrocytosis associated with megaloblastic anemia results from:

a. Reduced numbers of cell divisions with normal cytoplasmic development
b. Activation of a gene that is typically active only in megakaryocytes
c. Reduced concentration of hemoglobin in the cells so that larger cells are needed to provide the same oxygen-carrying capacity
d. Increased production of reticulocytes in an attempt to
compensate for the anemia

Answer 9

a. Reduced numbers of cell divisions with normal cytoplasmic development

Question 10

(10) Which one of the following groups has the highest risk for pernicious anemia?

a. Malnourished infants
b. Children during growth periods
c. Persons older than 60 years of age
d. Pregnant women

Answer 10

c. Persons older than 60 years of age