Info
🌱 來自: Huppert’s Notes
Qualitative Platelet Disorders🚧 施工中
Qualitative Platelet Disorders
• Definition: Normal platelet count but abnormal platelet function (i.e., normal platelet number but bleeding time is elevated)
• Etiologies:
- Von Willebrand Disease (vWD): Mixed platelet/coagulation disorder
• Pathophysiology: Defect or absence in vWF, which helps platelets aggregate when functioning appropriately. vWF is also a carrier for factor VIII.
• Clinical features: Prolonged PTT, mucocutaneous bleeding, heavy menstrual or post-partum bleeding
- Bernard-Soulier:
• Pathophysiology: Autosomal recessive disorder. ↓GpIb defect in platelet to vWF adhesion.
• Clinical features: Blood smear – platelets abnormally large, platelet count mildly low. Clinically, patients have bleeding out of proportion to their platelet number (which is often normal)
- Glanzmann’s thrombasthenia:
• Pathophysiology: Autosomal recessive disorder. ↓GpIIb/IIIa defect in platelet-to-platelet aggregation.
• Clinical features: Normal platelet count, no platelet clumping, mucocutaneous bleeding
- Acquired: Medications (ASA, NSAIDs, antibiotics), uremia (toxins affect vWF/XIII), liver disease, bone marrow disorders, dysproteinemias (multiple myeloma), antiplatelet antibodies, cardiopulmonary bypass (partial degranulation of platelets)
• Treatment: Platelet transfusions, DDAVP