2.2 Platelet and Vascular Disorders

Question 1

Thrombotic thrombocytopenic purpura (TTP) is characterized by:

Answer 1

Increased PLT aggregation

Question 2

Thrombocytopenia may be associated with:

Answer 2

Hypersplenism

Question 3

Aspirin prevents PLT aggregation by inhibiting the action of which enzyme?

Answer 3

Cyclo-oxygenase

Question 4

Normal PLT adhesion depends on:

Answer 4

Glycoprotein Ib

Question 5

Which of the following test results is normal in a patient with classic von Willebrand disease?

A. PLT aggregation
B. APTT
C. PLT count
D. Factor VIII:C and von Willebrand factor (VWF) levels

Answer 5

PLT count

Question 6

Bernard–Soulier syndrome is associated with:

Answer 6

Thrombocytopenia and giant PLTs

Question 7

When performing PLT aggregation studies, which set of PLT aggregation results would most likely be associated with Bernard–Soulier syndrome?

Answer 7

Normal PLT aggregation to collagen, ADP, and epinephrine (EPI); decreased aggregation to ristocetin

Question 8

Which set of PLT responses would be most likely associated with Glanzmann thrombasthenia?

Answer 8

Normal PLT aggregation to ristocetin; decreased aggregation to collagen, ADP, and EPI

Question 9

Which of the following is a characteristic of acute immune thrombocytopenic purpura?

Answer 9

Spontaneous remission within a few weeks

Question 10

TTP differs from DIC in that:

Answer 10

APTT is normal in TTP but prolonged in DIC

Question 11

Several hours after birth, a baby boy develops petechiae and purpura and hemorrhagic diathesis. The PLT count is 18 × 109/L. What is the most likely explanation for the low PLT count?

Answer 11

Neonatal alloimmune thrombocytopenia

Question 12

Which of the following is associated with post-transfusion purpura (PTP)?

Answer 12

Immune-mediated thrombocytopenia/alloantibodies

Question 13

Hemolytic uremic syndrome (HUS) is associated with:

Answer 13

Escherichia coli 0157:H7

Question 14

Storage pool deficiencies are defects of:

Answer 14

PLT granules

Question 15

Lumi-aggregation measures:

Answer 15

PLT aggregation and adenosine triphosphate (ATP) release

Question 16

Neurological findings may be commonly associated with which of the following disorders?

Answer 16

TTP

Question 17

Which of the following is correct regarding acquired TTP?

Answer 17

Autoimmune disease

Question 18

Hereditary hemorrhagic telangiectasia is a disorder of:

Answer 18

Connective tissue

Question 19

Which of the following prevents PLT aggregation?

A. TXA2
B. Thromboxane B2
C. Prostacyclin
D. Antithrombin (AT)

Answer 19

Prostacyclin

Question 20

Which defect characterizes Gray syndrome?

Answer 20

Alpha granule defect

Question 21

The P2Y12 ADP receptor agonist assay may be used to monitor PLT aggregation inhibition to which of the following drugs?

Answer 21

Clopidogrel (Plavix)

Question 22

Which of the following instruments can be used to evaluate PLT function?

A. PLT aggregometer
B. VerifyNow
C. PFA-100
D. All of the above

Answer 22

All of the above

Question 23

Which of the following PLT aggregating agents demonstrates a monophasic aggregation curve when used in the optimal concentration?

Answer 23

Collagen