Pre-4: Qualitative Disorders of Platelets Flashcards
Optical Platelet Aggregometry
Sample:
PRP
Optical Platelet Aggregometry
Principle
Light Transmittance
Whole Blood Aggregometry:
Sample
Whole blood
Whole Blood Aggregometry:
Principle
Electrical impedance
Platelet Lumi Aggregometry:
Sample
Both WB & PRP
Platelet Lumi Aggregometry:
Principle
Chemiluminescence
As platelets aggregates form, more light passes through the PRP and the tracing begins to move toward 100% light transmittance.
Optical Platelet Aggregometry
As Platelet aggregate, platelets collect on the electrodes impeding the current. The change is amplified and recorded.
Whole Blood Aggregometry
Reagent added in Platelet Lumi Aggregometry
Luciferin-luciferase enzyme
Biphasic Curve agonists:
Thrombin
ADP
Epinephrine
Monophasic Curve agonists:
Collagen
Arachidonic acid
Ristocetin
RECEPTORS of Thrombin
PAR-1, PAR4;
GPIba & GPVI
Receptors of ADP
P2Y1 & P2Y12
Receptors of Epinephrine
A2- Adrenergic receptor
Receptors of Collagen
GPIa/GPIIa & GPVI
Receptors of Arachidonic acid
TPa and TPb
Receptors of Ristocetin
GPIb/IX/V with vWF
GP Ib/IX/V complex is missing ‘
Bernard-Soulier Syndrome (Giant Platelet Syndrome)
Inability to bind to vWF accounts for the inability of platelet to adhere to exposed sub endothelium and results to the bleeding characteristics
Bernard-Soulier Syndrome (Giant Platelet Syndrome)
Laboratory feature: Giant Platelets
Bernard-Soulier Syndrome (Giant Platelet Syndrome)
Aggregometry: No aggregation to Ristocetin
Bernard-Soulier Syndrome (Giant Platelet Syndrome)
Deficiency/abnormality of GPIIb/IIIa
Glanzmann Thrombasthenia
Dense Granule Deficiency
- Hermansky-Pudlak Syndrome
- Chediak-Higashi Syndrome
- Wiskot-Aldrich Syndrome
- Thrombocytopenia Absent Radius (TAR) Syndrome
Alpha Granule Deficiency
Gray Platelet Syndrome
Chromosome 19 mutation
Hermansky-Pudlak Syndrome
Hallmark: Swiss-chess platelets (marked dilation)
Hermansky-Pudlak Syndrome
Mutations in Chromosome 1
Chediak-Higashi Syndrome
Giant lysosomal granules
Chediak-Higashi Syndrome
X-linked disease
Wiskot-Aldrich Syndrome
Mutations in the WAS gene on the short arm of the X chromosome (Xp11.23)
Wiskot-Aldrich Syndrome
Hallmark: TORCH infections
Wiskot-Aldrich Syndrome
Congenital absence of radial bones
Thrombocytopenia with Absent Radius Syndrome
(TAR)
Cardiac and skeletal abnormalities
Thrombocytopenia with Absent Radius Syndrome
(TAR)
Structural defects of platelet dense granules
Thrombocytopenia with Absent Radius Syndrome
(TAR)
Gray appearance in platelets in Wright’s stain
GRAY PLATELET SYNDROME
Characterized by: Large platelets
GRAY PLATELET SYNDROME
Mutations in the NBEAL2 gene (614169) on chromosome 3p21
GRAY PLATELET SYNDROME
The specific absence of morphologically recognizable alpha granules
GRAY PLATELET SYNDROME
Increased levels of Platelet factor 4 and B-thromboglobulin in the plasma
GRAY PLATELET SYNDROME
A rare disorder in which both alpha and dense granules are deficient
Alpha-Dense Storage Pool Deficiency
Autosomal dominant bleeding disorder which results to a deficiency in multimerin
Quebec Platelet Disorder
a multimeric protein that is stored complexed with factor V in the alpha granules of platelets
Multimerin
