Disorders of Platelet Adhesion (GP Ib/IX/V Function

Question 1

rare disorder of platelet adhesion that usually manifests in infancy or childhood with hemorrhage characteristic of defective platelet function: ecchymoses, epistaxis, and gingival bleeding

Answer 1

Bernard-Soulier (Giant Platelet) Syndrome

Question 2

In many respects this BSS resembles the defect seen in_. In contrast to it, however, this abnormality cannot be corrected by the addition of normal plasma or cryo- precipitate, consistent with a defect that resides in platelets.

Answer 2

VWD

Question 3

BSS

_ have enlarged platelets, thrombocytopenia, and usually decreased platelet survival

Answer 3

Homozygotes

Question 4

BSS

On peripheral blood films platelets typically are _ in diameter (normal 2 to 3 um), but they can be as large as _

Answer 4

5-8 um;

20 um

Question 5

Four glycoproteins are required to form the GP Ib/IX/V complex:

the complex these pro- teins are present in the ratio of _

Answer 5

GP Iba
GP IbB
GP IX
GP V

2:2:2:1

Question 6

The most frequent forms of BSS involve defects in _ synthesis or expression. It is essential to normal function because it contains binding sites for VWF and _.

Answer 6

GP Iba; thrombin

Question 7

The lack of response to _ is due to the lack of GP Ib/IX/V complexes and the inability of BSS platelets to bind VWF.

Answer 7

ristocetin

Question 8

BSS

Antifibrinolytic therapy may be useful to treat _ bleeding.

BSS patients tend to do better when _ are used for transfusion because this limits the number of donors to which the patient is exposed, and the rate of alloimmunization tends to be lower.

Answer 8

mucosal;

apheresis platelets

Question 9

platelets used to treat BSS should be_ (to reduce alloimmunization). Other treatments that have been used include desmopressin acetate (DDAVP) and, more recently, recombinant factor VIIa

Answer 9

pre-storage leukoreduced

Question 10

Inherited Giant Platelet Syndromes

• with abnormal microtubule distribution
• which platelets are spherical and have a prominent surface-connected canalicular system

Answer 10

May-Hegglin anomaly;

Epstein syndrome

Question 11

Giant platelets with velocardiofacial syndrome

Giant platelets with abnormal surface glycoproteins and mitral valve insufficiency

Familial macrothrombocytopenia with GP IV abnormality

Montreal platelet syndrome

May-Hegglin anomaly

Fechtner syndrome

Sebastian syndrome

Hereditary macrothrombocytopenia

Epstein syndrome

Mediterranean macrothrombocytopenia

Answer 11

Inherited Giant Platelet Syndromes