Medicine & USMLE

Glanzmann Thrombasthenia

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Platelet Disorders
  1. Platelet Plug Formation
  2. Von Willebrand Disease
  3. Bernard-Soulier Syndrome
  4. Glanzmann Thrombasthenia
  5. Immune Thrombocytopenic Purpura (ITP)
  6. Thrombotic Thrombocytopenic Purpura (TTP)
  7. Hemolytic Uremic Syndrome (HUS)
  8. Disseminated Intravascular Coagulation (DIC)

Summary

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Key Points

  • Glanzmann Thrombasthenia
    • Pathogenesis
      • Defect in GpIIb/IIIa receptors
        • Also known as integrin αIIbβ3
        • Impairs platelet aggregation via fibrinogen
        • Blocks formation of platelet plug
    • Genetics
      • Autosomal recessive inheritance
    • Presentation
      • Bleeding
        • Mucosal bleeding (e.g. gingival bleeding, epistaxis, menorrhagia)
        • Microhemorrhages (e.g. petechiae, bruising)
    • Diagnosis
      • Increased bleeding time
        • Due to defective primary hemostasis due to impaired platelet aggregation
      • Normal platelet count
      • No platelet clumping seen on peripheral smear
      • Normal ristocetin test
        • Adherence is normal since vWF and GpIb are unaffected
    • Treatment
      • Supportive
        • May require platelet transfusions during surgery or with severe bleeds