05 Platelet Disorders

Glanzman's

  • superficial bleeding
  • nl aggregation with ristocetin test

Bernard

  • large platelets on smear
  • abnormal ristocetin assay

WiskottAldrich

Acquired

  • ITP
  • TTP
  • HUS
  • DIC
  • Uremia
  • thrombocytopenia
  • vWF
  • Hayde's

ITP

  • don't live as long as they should = low number
  • macrophages clear antibody bound platelets

  • platelet thrombi: platelet low, coagulation factors not consumed

TTP

  • much more dangerous
  • low platelets, thrombosis
  • thrombus form in small vessels, consumes platelets, thrombocytopenia

  • TTP: build up of platelets and RBC, obstruction

  • small vessel occlusion in CNS

  • thrombi primarily made of platelets, do not consume clotting factor

  • platelet thrombi: platelet low, coagulation factors not consumed

HUS

  • distinguish from TTP: no fever or CNS symptoms (TTP only with kidney)

  • platelet thrombi: platelet low, coagulation factors not consumed

DIC

  • both platelets and fibrin, increased PT, PTT

  • TF activate coagulation cascade
  • sepsis: high levels of cytokines and endotoxins

  • every blood test abnormal

  • platelet thrombi: platelet low, coagulation factors not consumed

Uremia

  • caused by toxins, not platelets

Thrombocytopenia

Von Willebrand

  • heavy periods common early presentation

  • ristocetin test normal in glanzman
  • ristocetin test also abnormal in Bernard

Hayde's

  • aortic stenosis: increased risks of angiodysplasia
  • overactivity of ADAMST13, breaking down multimers, causing VWF to be less efficient