8. Aplastic Anemia Including Pure Red Cell Aplasia and Congenital Dyserythropoietic Anemia and Paroxysmal Noctural Hemoglobinuria (PNH)

Question 1

1.How is aplastic anemia best defined?
a.A condition in which bone marrow production of red cells, white blood cells,and platelets has failed
b.A condition in which severe anemia is seen
c.A condition in which platelets are decreased
d.A condition in which there is pancytopenia with a hypercellular bone marrow

Answer 1

a.A condition in which bone marrow production of red cells, white blood cells,and platelets has failed

Question 2

2.Which is the most common cause of aplastic anemia?
a.Drug ingestion
b.Toxin exposure
c.Idiopathic or unknown
d.Ionizing radiation

Answer 2

c.Idiopathic or unknown

Question 3

3.Which of the following represents the most complete list of etiologies causing aplastic anemia?

a.Secondaryand congenital
b. Idiopathic and congenital
c. Secondary and idiopathic
d. Secondary,idiopathic,and congenital

Answer 3

d. Secondary,idiopathic,and congenital

Question 4

4.Which of the following has not been associated with an acquired type of aplastic anemia?

a.Ionizing radiation
b.Increased chromosomal breakage
c.Chemical agents
d.Drugs

Answer 4

b.Increased chromosomal breakage

Question 5

5.The aplastic anemia associated with benzene exposure is characterized by which of the following statements?
a. Always occurs while the exposure to benzene is occurring
b. Is always irreversible
c.Always causes fatal,severe aplastic anemia
until several years following the benzene exposure
d. May cause a spectrum of disease that may not manifest until several years following the benzene exposure

Answer 5

d. May cause a spectrum of disease that may not manifest until several years following the benzene exposure

Question 6

6.Which of the following statements about chloramphenicol-induced aplastic anemia is true?

a.The onset of the bone marrow aplasia is not pre-dictable by the dose or the duration of drug exposure
b.Low doses of chloramphenicol never lead to aplastic anemias
c.People who receive chloramphenicol are 500 times more likely to develop aplastic anemia than the gen-eral population
d. The longer a patient receives chloramphenicol,the more likely it is that he or she will develop aplastic anemia

Answer 6

a.The onset of the bone marrow aplasia is not pre-dictable by the dose or the duration of drug exposure

Question 7

7.Which of the following drugs is not associated with the development of aplastic anemia?
a. Chloramphenicol
b.Phenylbutazone
c.Aspirin
d. Chemotherapeutic agents

Answer 7

c.Aspirin

Question 8

8.Ionizing radiation causes aplastic anemia by which of the following mechanisms?
a.A dose-dependent destruction of bone marrow stem cells
b.An idiosyncratic delayed development of bone marrow aplasia
c. Disruption of chemical bonds to form free radicals that damage bone marrow cells
d.All of the above

Answer 8

d.All of the above

Question 9

9.What is the most common congenital disorder associated with aplastic anemia?
a.Fanconi’s anemia
b.Thrombocytopenia-absent radius (TAR) syndrome
c.Congenital dyserythropoietic anemia,type 1
d.Diamond-Blackfan anemia

Answer 9

a.Fanconi’s anemia

Question 10

10.Which of the following is not seen in the peripheral blood of patients with aplastic anemia?
a.Normochromic,normocytic anemia
b.Increased reticulocyte count
c.Relative lymphocytosis
d.Decreased neutrophils

Answer 10

b.Increased reticulocyte count

Question 11

11.What is the appearance of the bone marrow in aplastic anemia?
a.Hypercellular
b.Normocellular
c.Hypocellular
d.Fibrotic

Answer 11

c.Hypocellular

Question 12

12. The differential diagnostic considerations for bone mar-row hypoplasia do not include which of the following disorders?

a.Severe malnutrition
b.Myeloproliferative disorder
c.Aplastic anemia
d.Recent chemotherapy

Answer 12

b.Myeloproliferative disorder

Question 13

13.What is the treatment of choice for severe aplastic ane-mia in patients who are younger than age 50?
a. Multiple transfusions
b.Androgens
c.Bone marrow transplantation
d.Erythropoietin therapy

Answer 13

c.Bone marrow transplantation

Question 14

14.What is the definition of pure red cell aplasia?
a. Lack of hematopoietic precursors in the bone marrow
b.Abnormal, giant normoblasts in the bone marrow
c.Lack of erythroid precursors with normal white blood cell and megakaryocytic precursors
d. Dysplastic red cell precursors with normal white cell and megakaryocytic precursors

Answer 14

c.Lack of erythroid precursors with normal white blood cell and megakaryocytic precursors

Question 15

15.What features do the congenital dyserythropoietic ane-mias (CDAs)have in common?
a.Anemia, microcytosis, erythroid hyperplasia, and abnormal erythrobasts
b. Anemia, erythroid hyperplasia with abnormal erythroblasts, and indirect hyperbilirubinemia
c. Anemia, lysis in acidified serum, and indirect hyper-bilirubinemia
d.Anemia, macrocytosis,erythroid hyperplasia with abnormal erythroblasts,and indirect hyperbilirubinemia

Answer 15

b. Anemia, erythroid hyperplasia with abnormal erythroblasts, and indirect hyperbilirubinemia

Question 16

16.Which statement best describes paroxysmal nocturnal hemoglobinuria?
a.Acquired hemolytic anemia associated with cellular membrane abnormalities
b.Congenital hemolytic anemia associated with the inflammatory response
c.A premalignant condition that almost always results in development of acute leukemia.
d.A common disorder that frequently resolves with time.

Answer 16

a.Acquired hemolytic anemia associated with cellular membrane abnormalities

Question 17

17.What causes the red cell defect of PNH?
a.Rare red cell antigens
b.Lack of GPI-anchored proteins on the erythrocyte membrane
c.Excessive amounts of complement components C5 to C9
d.Glucose-6-phosphate dehydrogenase enzyme deficiency

Answer 17

b.Lack of GPI-anchored proteins on the erythrocyte membrane

Question 18

18.Which of the following is a correct description of the sugar water test (sucrose hemolysis test)?
a.PNH cells are lysed by complement after exposure to low-ionic-strength sugar water.
b. PNH cells are lysed by antibody and complement after heating to 56C in sugar water solution (5%).
c. Patient’s serum is acidified to enhance complement binding and lysis of patient cells.
d.Patient’s serum is heat-inactivated and treated with HCI; complement is added; patient cell lysis occurs

Answer 18

a.PNH cells are lysed by complement after exposure to low-ionic-strength sugar water.

Question 19

19. What is a correct description of Ham’s test (acidified serum lysis test)?
    a. PNH cells are lysed by complement after exposure to low-ionic-strength sugar water.
    b. PNH cells are lysed by antibody and complement after heating to 56C in sugar water solution(5%).
    c. Patient’s serum is acidified to enhance complement binding and lysis of patient cells.
    d.Patient’s serum is heat inactivated and treated with HCI; complement is added; patient cell lysis occurs.

Answer 19

c. Patient’s serum is acidified to enhance complement binding and lysis of patient cells.

Question 20

20. The basis of the flow cytometric test for diagnosis of PNH is which of the following?
    a. PNH will have increased amounts of complement detected on the cell surface.
    b. PNH cells are easily lysed and will show decreased number when analyzed.
    c. An affected patient will show decreased levels of CD55 and CD59 binding in a subset of cells.
    d. All of the patient cells will show decreased levels of GPI-anchored proteins on the erythrocyte membrane.

Answer 20

c. An affected patient will show decreased levels of CD55 and CD59 binding in a subset of cells.