Deck 41: Qualitative Disorders of Platelets and Vasculature

Question 1

Which of the following is a disorder with absent platelet glycoprotein Ib/IX/V and in which the patient has moderate thrombocytopenia,large platelets,and normal aggregometry with all agents except ristocetin?

A)von Willebrand disorder (VWD)
B)Bernard-Soulier syndrome
C)Glanzmann thrombasthenia
D)dense granule deficiency

Answer 1

Bernard-Soulier syndrome

Question 2

Which of the following is true regarding testing for the diagnosis of vascular disorders?

A)Most do not have abnormal clinical laboratory tests.
B)The platelet count and aggregometry are useful.
C)The prothrombin time (PT) and partial thromboplastin time (PTT) are most useful.
D)Evaluation of von Willebrand factor (VWF) is useful.

Answer 2

Most do not have abnormal clinical laboratory tests.

Question 3

Which of the following is normal in a patient regularly taking aspirin?

A)platelet aggregation
B)platelet cyclooxygenase function
C)synthesis of thromboxane A2
D)platelet count

Answer 3

platelet count

Question 4

Which of the following is the most common cause of acquired platelet dysfunction?

A)myeloproliferative disorders
B)Wiskott-Aldrich syndrome
C)drugs, especially aspirin
D)afibrinogenemia

Question 5

What is the mechanism for the platelet dysfunction in multiple myeloma and Waldenström macroglobulinemia?

A)Granules become deficient.
B)Platelets are coated with paraprotein.
C)Nitric oxide is not produced.
D)Cyclooxygenase is acetylated.

Question 6

Which of the following is the most likely diagnosis for a patient with a normal platelet count and no aggregation with any agent except ristocetin?

A)aspirin ingestion
B)gray platelet syndrome
C)vitamin C deficiency
D)Glanzmann thrombasthenia

Question 7

What types of hemostatic complications are found in patients with myeloproliferative disorders?

A)hemorrhagic
B)thrombotic
C)abnormal platelet function
D)all of the above

Question 8

All of the following are common conditions or situations that interfere with platelet function except

A)liver disease
B)uremia
C)allergic purpura
D)cardiopulmonary bypass surgery

Question 9

A 78-year-old patient recently noticed dark blotches on his forearms and on the backs of his hands.He seems to bruise even when a phlebotomy is performed using excellent technique with no problems encountered.No other symptoms exist,and all laboratory tests are normal.Which of the following is the most likely diagnosis?

A)hereditary hemorrhagic telangiectasia
B)Ehlers-Danlos syndrome
C)paraproteinemia and amyloidosis
D)senile purpura

Question 10

Clopidogrel (Plavix)is a drug used therapeutically for patients with a risk of arterial thrombi because it

A)inhibits thrombin.
B)activates the protein C pathway.
C)inhibits platelet function.
D)activates plasminogen.

Question 11

Platelet count and function studies are performed on a patient with a history of easy bruising,and the following results are obtained:
$\begin{array}{ll}\underline { \text { Test }}&\underline { \text { Result }}\\\text { Platelet count } & 295 \times 10^{9} / \mathrm{L} \\\text { Platelet function assay } & \text { Prolonged } \\\text { Platelet aggregation with epinephrine } & \text { Primary but no secondary wave } \\\text { Platelet aggregation with low-dose adenosine } & \text { Primary but no secondary wave }\\\text { diphosphate (ADP) }\\\text { Platelet agoregation with ristocetin }& \text { Normal }\\\end{array}$
What is the most likely diagnosis for this patient?

A)Bernard-Soulier disease
B)dense granule deficiency
C)Glanzmann thrombasthenia
D)gray platelet syndrome

Question 12

The qualitative platelet disorders and vascular disorders typically exhibit what type of symptoms?

A)superficial bleeding
B)deep tissue bleeding
C)hemarthrosis
D)thrombosis