Giant platelets on a blood smear may indicate which disorder?

Giant platelets on a blood smear may indicate which disorder?

• A. Bernard-Soulier
• B. von Willebrand Disease
• C. Glanzmann thrombocytopenia
• D. Ehlers-Danlos

Answer: (A)

Giant platelets indicate a macrothrombocytopenia due to a platelet adhesion defect. In Bernard-Soulier syndrome, there is a deficiency of the GPIb-IX-V receptor complex, which binds von Willebrand factor to platelets. Without proper adhesion, platelets are produced abnormally and often appear as unusually large on smear, giving the giant-platelet picture. This condition also typically features thrombocytopenia and a bleeding tendency. By contrast, von Willebrand disease involves deficient or defective von Willebrand factor but platelets are usually normal in size and number, with the adhesion defect arising from VWF itself rather than platelet size. Glanzmann thrombocytopenia stems from a defect in the GPIIb/IIIa complex needed for platelet aggregation, and platelets are generally normal in size. Ehlers-Danlos is a connective tissue disorder with bleeding risk not driven by giant platelets, so the smear would not show large platelets.

Giant platelets indicate a macrothrombocytopenia due to a platelet adhesion defect. In Bernard-Soulier syndrome, there is a deficiency of the GPIb-IX-V receptor complex, which binds von Willebrand factor to platelets. Without proper adhesion, platelets are produced abnormally and often appear as unusually large on smear, giving the giant-platelet picture. This condition also typically features thrombocytopenia and a bleeding tendency.

By contrast, von Willebrand disease involves deficient or defective von Willebrand factor but platelets are usually normal in size and number, with the adhesion defect arising from VWF itself rather than platelet size. Glanzmann thrombocytopenia stems from a defect in the GPIIb/IIIa complex needed for platelet aggregation, and platelets are generally normal in size. Ehlers-Danlos is a connective tissue disorder with bleeding risk not driven by giant platelets, so the smear would not show large platelets.