111 Disorders of Platelets and Vessel Wall

Question 1

Average lifespan of platelets (H20 C111 P823)

Answer 1

7-10 days

Question 2

In vitro artifact resulting from platelet agglutination via antibodies when the calcium content is decreased by blood collection in EDTA (H20 C111 P823)

Answer 2

Peudothrombocytopenia

Question 3

Patients with isolated thrombocytopenia who are at least this age should have their bone marrow examined (H20 C111 P823)

Answer 3

60 years

Question 4

Clinical manifestation that is thought to denote an increased risk of life-threatening hemorrhage in the thrombocytopenic patient (H20 C111 P823)

Answer 4

Wet purpura

Question 5

Most common cause of thrombocytopenia (H20 C111 P823)

Answer 5

Drugs

Question 6

Drugs usually induce thrombocytopenia after a median length of 21 days. However, this drug class differs in that it can induce thrombocytopenia within 24 h of intial exposure. (H20 C111 P825)

Answer 6

Gp IIb/IIIa inhibitory drugs, e.g. abciximab

Question 7

Nadir platelet counts in HIT are rarely below: (H20 C111 P825)

Answer 7

20,000/µL

Question 8

Most patients develop HIT after exposure to heparin for how many days? (H20 C111 P825)

Answer 8

5-14 days

Question 9

Most widely available test to detect HIT antibodies (H20 C111 P825)

Answer 9

ELISA with PF4/polyanion complex

Question 10

An increased risk of thrombosis is present for at least how long after diagnosis of HIT (H20 C111 P825)

Answer 10

1 month

Question 11

In addition to wet purpura, this sign may also herald life-threatening bleeding in ITP (H20 C111 P825)

Answer 11

Retinal hemorrhages

Question 12

If anemia is present in a patient with ITP, this test should be done (H20 C111 P826)

Answer 12

Direct antiglobulin testing / Coombs test (to rule out Evans syndrome)

Question 13

This platelet count is required to maintain vascular integrity (H20 C111 P823)

Answer 13

~5,000-10,000/µL

Question 14

IVIgG has more efficacy than anti-Rh0(D) in these patients (H20 C111 P826)

Answer 14

Postsplenectomized patients

Question 15

Oral TPO receptor agonist that is effective in raising platelet counts in patients with ITP (H20 C111 P826)

Answer 15

Elthrombopag

Question 16

SC TPO receptor agonist that is effective in raising platelet counts in patients with ITP (H20 C111 P826)

Answer 16

Romiplostim

Question 17

Common feature of the many forms of autosomal dominant thrombocytopenia (H20 C111 P826)

Answer 17

Large platelets

Question 18

Functional platelet disorder due to absence of Gp Ib-IX-V (H20 C111 P826)

Answer 18

Bernard-Soulier syndrome

Question 19

Inherited TTP (H20 C111 P826)

Answer 19

Upshaw-Shulman syndrome

Question 20

Mainstay of treatment of TTP (H20 C111 P827)

Answer 20

Plasma exchange

Question 21

Markedly elevated platelet counts above this value is a risk factor for bleeding (H20 C111 P827)

Answer 21

> 1.5 million/µL

Question 22

Glanzmann thrombasthenia is an autosomal recessive disorder that is characterized by the absence of: (H20 C111 P827)

Answer 22

Platelet Gp IIb/IIIa receptor

Question 23

Humanized monoclonal antibody against C5 that has efficacy in preserving renal function in HUS (H20 C111 P827)

Answer 23

Eculizumab

Question 24

Inherited disorders of platelet dysfunction would require transfusion of: (H20 C111 P828)

Answer 24

HLA-matched leuko-depleted platelet concentrates

Question 25

Inherited disorders of platelet dysfunction with milder bleeding symptoms would frequently respond to: (H20 C111 P828)

Answer 25

DDAVP

Question 26

The platelet defect in uremia may be improved by increasing hematocrit to: (H20 C111 P828)

Answer 26

27-32%

Question 27

DDAVP increases the levels of this coagulation factor (H20 C111 P828)

Answer 27

Factor VIII

Question 28

Most common inherited disorder (H20 C111 P828)

Answer 28

Von Willebrand disease

Question 29

The normal range for VWF proteins of patients with this blood type overlaps that which has been considered diagnostic for VWD (H20 C111 P828)

Answer 29

Type O

Question 30

Most common type of VWD (H20 C111 P828)

Answer 30

Type 1 VWD

Question 31

VWD type 2N is also termed: (H20 C111 P828)

Answer 31

Autosomal hemophilia

Question 32

Syndrome characterized by aortic stenosis and angiodysplasia of the GI tract causing bleeding (H20 C111 P829)

Answer 32

Heyde syndrome

Question 33

Usual dose of IV DDAVP (H20 C111 P829)

Answer 33

0.3 µg/kg