Platelet Qualitative Disorder

Question 1

an instrument designed to measure
platelet function in a suspension of Citrated WB or PRP.

Answer 1

Aggregometer

Question 2

TYPES OF PLATELET AGGREGOMETRY STUDIES

Answer 2

1. Optical platelet aggregometry
2. Whole blood platelet aggregometry
3. Platelet lumi aggregometry

Question 3

Sample used in Optical platelet aggregometry

Answer 3

PRP

Question 4

Testing principle of Optical platelet aggregometry

Answer 4

Light transmittance

Question 5

Baseline 0% Transmission scales down to 100% transmittance.

Answer 5

Optical platelet aggregometry

Question 6

4 PHASES of Optical platelet aggregometry

Answer 6

1. Baseline
2. Primary-wave aggregation
3. ADP/ATP release
4. Second-wave aggregation

Question 7

Sample used in Whole blood platelet Aggregometry

Answer 7

Whole blood (WB)

Question 8

Testing principle of Whole blood platelet Aggregometry

Answer 8

Electrical impedance

Question 9

As platelet aggregate, platelets collects on
the electrodes impeding the current. The change is amplified and recorded.

Answer 9

Whole blood platelet Aggregometry

Question 10

Sample used in Platelet lumi Aggregometry

Answer 10

Whole blood (WB) or PRP

Question 11

Testing principle of Platelet lumi Aggregometry

Answer 11

Chemiluminescence

Question 12

Principle: Luciferin-luciferase enzyme (Reagent) added is oxidized by ATP which generates proportional chemiluminescence

Answer 12

Platelet lumi Aggregometry

Question 13

Particularly sensitive to ATP release

Answer 13

Platelet lumi Aggregometry

Question 14

AGONIST USED IN AGGREGOMETRY with Biphasic curves

Answer 14

• Thrombin
• ADP
• Epinephrine

Question 15

AGONIST USED IN AGGREGOMETRY with Monophasic curves

Answer 15

• Collagen
• Arachidonic Acid
• Ristocetin

Question 16

Receptors of Thrombin

Answer 16

PAR-1,PAR-4;
GP Iba & GP VI

Question 17

Relatively unaffected by membrane disorders or enzyme deficiencies.

Answer 17

Thrombin

Question 18

Receptors for ADP

Answer 18

P2Y1 & P2Y12

Question 19

Most commonly used agonists.

Answer 19

ADP

Question 20

Receptor for EPINEPHRINE

Answer 20

A2- Adrenergic Receptor

Question 21

Cannot induce aggregation in storage pool disorders

Answer 21

EPINEPHRINE

Question 22

Receptors for COLLAGEN

Answer 22

GP Ia/IIa & GPVI

Question 23

Loss of response may indicate membrane abnormality, secretion defect or antiplatelet
drugs

Answer 23

COLLAGEN

Question 24

Receptors for ARACHIDONIC ACID

Answer 24

TPa & TPb

Question 25

Assess platelet eicosanoid pathway

Answer 25

ARACHIDONIC ACID

Question 26

Receptor for RISTOCETIN

Answer 26

GP Ib/IX/ V with vWf

Question 27

For the diagnosis of BSS and vWf

Answer 27

RISTOCETIN

Question 28

Disorders of Platelet Adhesion:

Answer 28

Bernard-Soulier Syndrome (Giant platelet syndrome)

Question 29

Inherited as Autosomal Recessive disorder in which the GP Ib/1X/V complex is missing from the platelet surface or exhibits abnormal function.

Answer 29

Bernard-Soulier Syndrome (Giant platelet syndrome)

Question 30

Inability to bind to VWF accounts for the inability of platelets to adhere to exposed sub endothelium and results to the bleeding characteristics of this disorder.

Answer 30

Bernard-Soulier Syndrome (Giant platelet syndrome)

Question 31

Laboratory features : Giant platelets

Answer 31

Bernard-Soulier Syndrome (Giant platelet syndrome)

Question 32

PLATELET AGGREGATION in PLASMA OR PLATELET GRANULES

Answer 32

- Ionized Calcium - Fibrinogen

Question 33

PLATELET AGGREGATION in PLATELETS

Answer 33

- GP IIb/IIIa - ATP/ADP

Question 34

Disorders of Platelet Aggregation:

Answer 34

Glanzmann Thrombasthenia

Question 35

Deficiency or abnormality of the platelet membrane glycoprotein GPIlb/Illa complex.

Answer 35

Glanzmann Thrombasthenia

Question 36

Laboratory features : Platelet aggregometry. Macrothrombocytopenia and prolonged bleeding time.

Answer 36

Bernard-Soulier Syndrome (Giant platelet syndrome)

Question 37

Normal platelet count and morphology. Abnormal aggregation. Prolonged bleeding time.

Answer 37

Glanzmann Thrombasthenia

Question 38

Clinical Manifestations: Bleeding of all types

Answer 38

Glanzmann Thrombasthenia

Question 39

Dense Granule Deficiency:

Answer 39

1. Hermansky-Pudlak syndrome 1. Chediak- Higashi syndrome 2. Wiskott-ALdrich syndrome 3. Thrombocytopenia-absent 4. radius (TAR) syndrome

Question 40

Alpha Granule Deficiency:

Answer 40

1. Gray Platelet Syndrome

Question 41

Manifestations: - Tyrosinase positive oculocutaneous albinism - Lysosomal dysfunctions - Ceroid-like depositions in the RES - Profound platelet dense granule deficiency. - Severe bleeding is RARE.

Answer 41

Hermansky- Pudlak Syndrome

Question 42

Hallmark: Swiss-cheese platelets. This abnormality consists of marked dilation and tortuosity of the surface-connecting tubular system

Answer 42

Hermansky- Pudlak Syndrome

Question 43

Manifestations: - Partial oculocutaneous albinism - Frequent pyogenic bacterial infections (severe immunology defects). - Giant lysosomal granules - Platelet dense granule deficiency (which leads to hemorrhage ). - Lymphocytic proliferation in the liver, spleen and marrow. - Macrophage accumulation in tissues. - Severe pancytopenia - Usually results to death in early age.

Answer 43

Chediak-Higashi Syndrome

Question 44

- X-linked disease - Affects primarily males. - Mutations in the WAS gene on the short arm of the X chromosome. (Xp11.23)

Answer 44

Wiskott-Aldrich syndrome

Question 45

The WASp gene plays a crucial role in

Answer 45

actin cytoskeleton remodeling

Question 46

Classic form of WAS:

Answer 46

Eczema-thrombocytopenia immunodeficiency syndrome

Question 47

- Immune dysfunction (susceptibility to bacterial, viral and fungal infections). - Microthrombocytopenia - Severe Eczema. - Bleeding episodes (mod-severe).

Answer 47

Eczema-thrombocytopenia immunodeficiency syndrome

Question 48

1. Decreased platelet dense granules. 2. Platelets are small- Microthrombocytes. Other instances where small platelets are hallmark features: TORCH Infections. ( bacterial infection that transmitted vertically from mother to the baby)

Answer 48

Wiskott-Aldrich syndrome

Question 49

- Rare autosomal recessive disorder - Congenital absence of radial bones - Cardiac and skeletal abnormalities - Thrombocytopenia - Structural defects of platelet dense granules.

Answer 49

Thrombocytopenia with absent radii syndrome (TAR)

Question 50

mutation in the NBEAL2 gene (614169) on chromosome 3p21.

Answer 50

Gray Platelet Syndrome

Question 51

Characterized by the specific absence of morphologically recognizable alpha granules.

Answer 51

Gray Platelet Syndrome

Question 52

- Lifelong mild bleeding tendencies. - Moderate thrombocytopenia - Fibrosis of the marrow - Large platelets with gray appearance on a wright-stained smear.

Answer 52

Gray Platelet Syndrome

Question 53

Membranes & precursors of gray platelet syndrome have

Answer 53

P-selectin and GPIIB/IlIA expressions

Question 54

a rare disorder in which both alpha and dense granules are deficient. Inherited in an autosomal dominant manner.

Answer 54

Alpha-Dense storage pool deficiency

Question 55

autosomal dominant bleeding disorder, this results to a deficiency in multimerin. Many alpha granules are degraded by proteases.

Answer 55

Quebec Platelet disorder

Question 56

DRUGS INFLUENCING PLATELET FUNCTIONS

Answer 56

- Aspirin - Clopidogrel - Tirofiban - Atopaxar

Question 57

Inhibits platelet aggregation and secretion in response to ADP, Epinephrine and collagen.

Answer 57

ASPIRIN

Question 58

inhibits prostaglandin synthesis by irreversible acetylation and inactivation of cyclooxygenase (COX-1)thereby inhibiting endoperoxide and thromboxane A2 which are necessary for platelet secretion.

Answer 58

Aspirin

Question 59

a thienopyridine derivative, binds specifically and irreversibly to the platelet P2RY12 purinergic receptor, inhibiting ADP-mediated platelet activation and aggregation.

Answer 59

CLOPIDOGREL

Question 60

a reversible, competitive inhibitor of GP Ilb/Illa receptors, exerting its effects via the prevention of the binding of fibrinogen and other ligands, resulting in the inhibition of platelet aggregation.

Answer 60

TIROFIBAN

Question 61

is a potent protease-activated receptor (PAR-1) antagonist targeting the G-coupled receptor and modulating thrombin-platelet-endothelial interactions.

Answer 61

Atopaxar (E5555)