Info
🌱 來自: Huppert’s Notes
Mixed PlateletCoagulation Disorders🚧 施工中
Mixed Platelet/Coagulation Disorders
Disseminated intravascular coagulation (DIC)
• Pathophysiology: Tissue factor release (e.g., gram negative sepsis, obstetric complications, APML, trauma) or other procoagulant (e.g., cancer). Tissue factor activates coagulation and fibrinolysis, causing platelet consumption, and leading to both bleeding and clotting.
• Clinical features: Can have both bleeding AND clotting
- Bleeding – superficial purpura, GI or intracranial bleed, oozing from incisions
- Clotting – stroke, DVT/PE
• Diagnosis: ↓fibrinogen (used up from clotting; a normal level rules out DIC), ↑D-dimer, ↓platelets, ↓factor V/VIII, ↑bleeding time, ↑PTT/PT, schistocytes on blood smear
• Treatment: Treat underlying condition; supportive care with FFP, platelets, cryoprecipitate
Von Willebrand’s disease (vWD)
• Pathophysiology: Autosomal dominant disorder – vWF deficiency
- vWF: Involved in platelet aggregation, binds to and stabilizes factor VIII (deficiency leads to ↓VIII levels)
- Types: 1) Quantitative problem (low vWF levels), 2) Qualitative problem with vWF, 3) Absent vWF
• Clinical features: Family history of bleeding, cutaneous and mucosal bleeding, menorrhagia
• Diagnosis: ↑Bleeding time, ↑PTT (↓VIII), normal platelet count, ↓vWF antigen, ↓vWF activity (ristocetin cofactor assay, measures affinity of vWF binding to GP1b), ↓factor VIII activity in severe disease
• Treatment: DDAVP (desmopressin) releases vWF in endothelium (type I); vWF concentrate; factor VIII concentrate after trauma or for Type 3. Avoid ASA/NSAIDs.