Hema 4 Part 4 - QUALITATIVE PLATELET DISORDERS Flashcards
(35 cards)
QUALITATIVE PLATELET DISORDERS
INHERITED DEFECTS
ACQURIED
Inherited defects include
adhesion defects
aggregation defects
release defects
Adhesion defects include
giant platelet syndrome
Von willebrand’s disease
What is Bernard-Soulier Syndrome also known as?
Giant platelet syndrome
What is the inheritance pattern of Bernard-Soulier Syndrome?
Autosomal recessive
What is the primary defect in Bernard-Soulier Syndrome?
Lack of membrane receptor GpIb/IX/V
What are the key characteristics of Bernard-Soulier Syndrome?
Presence of giant platelets
Severe bleeding in homozygotes
What are the laboratory findings of Bernard-Soulier Syndrome?
BT (Bleeding Time): Prolonged
PLT (Platelet Count): Abnormal
Clot Retraction: Normal
Normal aggregation with: ADP, epinephrine, collagen, arachidonic acid
Does not respond to Ristocetin agglutination
What characterizes Von Willebrand’s Disease?
A: A decrease in production of vWF or production of a dysfunctional protein
What is the main functional defect in Von Willebrand’s Disease?
A: Impaired platelet adhesion and aggregation due to defective vWF
What are the FOUR main types of platelet disorders?
- Adhesion Defects (e.g., Bernard-Soulier Syndrome, Von Willebrand’s Disease)
- Aggregation Defects (e.g., Glanzmann’s Thrombasthenia, AFIBRINOGENEMIA)
- Release disorders
- Inherited disorders of other receptors and signaling pathway
What is the inheritance pattern of Glanzmann’s Thrombasthenia?
A: Autosomal recessive
What is the primary defect in Glanzmann’s Thrombasthenia?
A: Lack of Gp IIb-IIIa, which is necessary for platelet aggregation
What are the types of Glanzmann’s Thrombasthenia?
- Type 1: Undetectable or trace amounts (<5%) of Gp IIb-IIIa
- Type 2: Up to 15% of normal Gp IIb-IIIa
- Type 3: Qualitative defect with levels 50–100% of normal
What are the laboratory findings of Glanzmann’s Thrombasthenia?
A:
Platelet count: Normal
CTBT (Clotting Time and Bleeding Time) and CR (Clot Retraction): Prolonged
Platelets aggregate/agglutinate only in the presence of Ristocetin
What are Release Disorders in platelet function?
A: Abnormal secondary platelet aggregation that requires ADP.
in storage pool defects what are under it?
Alpha granule storaget pool defect
Dense granule storage pool defect
Granule release or platelet secretory mechanism abnormalitites
What are Storage Pool Defects?
: A group of platelet disorders characterized by a lack of alpha or beta granules.
What is Gray Platelet Syndrome (α-Storage Pool Disease)?
A: A disorder caused by a lack of alpha granules
What is Quebec Platelet Disorder?
A:
A rare autosomal dominant disorder associated with proteolysis of alpha granule proteins due to increased levels of platelet urinary-type plasminogen activator.
giant alpha granules that most cant release contents
Jacobsen’s syndrome
What is Dense Granule Storage Pool Defect?
A: A disorder where platelets are morphologically normal but lack dense granules.
What are the laboratory findings in Dense Granule Storage Pool Defect?
Aggregation with ristocetin: Normal
Aggregation with ADP and collagen: Greatly reduced
Absent or blunted secondary aggregation with epinephrine
What is TAR Syndrome?
A: A disorder characterized by isolated hypoplasia of the megakaryocyte lineage, thrombocytopenia, and bilateral radial aplasia.
