Platelets: Qualitative & Quantitative Disorders Flashcards Preview

Hemostasis/Coag > Platelets: Qualitative & Quantitative Disorders > Flashcards

Flashcards in Platelets: Qualitative & Quantitative Disorders Deck (26):
1

State three functions of von Willebrand Factor (vWF)

-carrier protein for Factor VIII (VIII:C)
-participates in Platelet's adhesion to subendothelial collagen
-Facilitates a normal aggregation response to ristocetin

2

Discuss von Willebrand disease: Pathogenesis

Clinical disorder due to deficiency of von Willebrand factor

3

Discuss von Willebrand disease: Bleeding time results

Increased

4

Discuss von Willebrand disease: closure time results (PFA)

Increased

5

Discuss von Willebrand disease: platelet adhesion result

Abnormal

6

Discuss von Willebrand disease: platelet aggregation with ristocetin

Abnormal ristocetin induced aggregation

7

Discuss von Willebrand disease: platelet count

can be normal or abnormal - not a hallmark

8

Discuss von Willebrand disease: APTT result

Prolonged due to decrease VIII:C

9

Discuss Bernard-Soulier syndrome: Pathogenesis

Missing GPIb/IX receptor complex: Platelets cannot adhere to subendothelium via vWF

10

Discuss Bernard-Soulier syndrome: bleeding time result

Prolonged

11

Discuss Bernard-Soulier syndrome: platelet aggregation with ADP & ristocetin

ADP: normal
Ristocetin: Abnormal

12

Discuss Bernard-Soulier syndrome: platelet adhesion result

Abnormal

13

Discuss Bernard-Soulier syndrome: platelet count

Decreased

14

Discuss Bernard-Soulier syndrome: platelet morphology

Giant platelets

15

Discuss Glanzmann's thrombasthenia: Pathogenesis

Missing GPIIb/IIIa receptor complex: platelets cannot bind to fibrinogen and bridge/attach to one another---aggregate

16

Discuss Glanzmann's thrombasthenia: bleeding time result

Prolonged

17

Discuss Glanzmann's thrombasthenia: platelet adhesion result

Normal

18

Discuss Glanzmann's thrombasthenia: platelet aggregation with ADP and Ristocetin

ADP: abnormal
Ristocetin: normal

19

Discuss Glanzmann's thrombasthenia: platelet count

Normal

20

Discuss Glanzmann's thrombasthenia: platelet morphology

Normal

21

List five acquired qualitative platelet disorders

-drug therapy (most common cause)
-Renal disease-uremia
-Dysproteinemias
-liver disease
-platelet antibodies

22

List four general causes for thrombocytopenia.

-decreased platelet production
-ineffective thrombopoiesis
-abnormal distribution of platelets
-increased destruction of platelets

23

Destruction occurs by processes other than the immune system (consumption, mechanical destruction).

Non-immune mediated platelet destruction

24

Platelets become sensitized with antibody and RES, especially the spleen, destroys them

immune mediated platelet destruction

25

List three causes of non-immune mediated platelet destruction for thrombocytopenia

-Thrombotic thrombocytopenic purpura (TTP)
-Hemolytic uremic syndrome (HUS)
-Disseminated intravascular coagulation (DIC)

26

List three causes of immune mediated platelet destruction for thrombocytopenia

-Idiopthic thrombocytopenic purpura (ITP)
-drug-induced -> Heparin-induced thrombocytopenia (HIT)
-Neonatal alloimmune thrombocytopenia