Qualitative platelet disorder Flashcards
Platelets are defective in function but count is usually normal
DISORDERS OF PRIMARY HEMOSTASIS:
QUALITATIVE PLATELETS DISORDERS
Petechiae, ecchymosis, epistaxis, gingival bleeding, purpura
Associated with platelet defect or vascular disorder
Superficial Bleeding
Hematoma and hemarthroses (bleeding of the joints)
Associated with plasma coagulation factor deficiencies
Deep Tissue Bleeding
Capillary Fragility Test (Tourniquet Test or Vitamin C Resistant Test)
Abnormal
Platelet Function Test
Abnormal
bleeding time
Prolonged
Platelet Adhesiveness Test
Abnormal
Platelet Aggregation Test
Abnormal
Clot Retraction Time
Abnormal
Aka Hemorrhagiparous Thrombocytic Dystrophy / Giant Platelet Syndrome
Rare autosomal-recessive disorder
Defect in quantitative decrease or abnormal function of the GPIb/IX/V complexes
BERNARD-SOULIER SYNDROME
Characterized by thrombocytopenia, giant platelets (Size: 8 - 20 um), and failure of the platelets to bind GPIb ligands (von Willebrand factor and thrombin)
NOTE: Diathesis - habit of the body
Possible Therapy:
Platelet transfusion – using apheresis platelets (to reduce the rate of alloantibodies)
Desmopressin acetate (DDAVP) – shortens the bleeding time
Recombinant factor VIIa – stops the bleeding
Oral contraceptive – for menorrhagia
BERNARD-SOULIER SYNDROME
Thrombocytopenia
Von Willebrand factor
Abnormal platelet interactions with thrombin
Abnormal platelet coagulant activity
Abnormal platelet interactions with P-selectin (for cell adhesion and found in activated subendothelial)
Abnormal platelet interactions with leukocyte integrin αмβ2 (for cell adhesion)
BERNARD-SOULIER SYNDROME
chromosome:
GP1b (vWF – for adhesion)
Chromosome 17
BERNARD-SOULIER SYNDROME
- GP1bβ Chromosome 22
Chromosome 22
BERNARD-SOULIER SYNDROME
GPIX
Chromosome 3
BERNARD-SOULIER SYNDROME
