From the Guidelines
Bernard-Soulier Syndrome (BSS) and Glanzmann Thrombasthenia (GT) are distinct inherited platelet disorders with different underlying mechanisms, clinical presentations, and diagnostic approaches, as outlined in the 2015 guidance from the SSC of the ISTH 1. The key differences between BSS and GT lie in their underlying receptor defects: BSS is characterized by defects in the GPIb-IX-V complex, while GT is caused by defects in the platelet GPIIb/IIIa receptor (integrin αIIbβ3) 1. Some of the key features of these disorders include:
- BSS: giant platelets, reduced platelet counts, and mucocutaneous bleeding, including epistaxis, gingival bleeding, and menorrhagia
- GT: normal platelet count and morphology, but severely impaired platelet function, with poor aggregation in response to multiple agonists Diagnosis of these conditions involves platelet function tests, including flow cytometry screening using antibodies against specific glycoproteins, such as GPIIb/IIIa (CD41), GPIIIa (CD61), GPIb (CD42b), and GPIb/IX (CD42a) 1. The most effective diagnostic approach for BSS and GT involves a combination of first-step tests, including flow cytometry and light transmission aggregometry (LTA), followed by second-step tests, such as LTA with an expanded agonist panel and measurement of serum TxB2 1. Treatment for both disorders focuses on managing bleeding episodes, with options including:
- Platelet transfusions
- Antifibrinolytics like tranexamic acid
- Recombinant factor VIIa for severe bleeding It is essential for patients with BSS and GT to avoid aspirin and NSAIDs, which can further impair platelet function 1.
From the Research
Comparison of Bernard-Soulier Syndrome (BSS) and Glanzmann Thrombasthenia (GT)
- Both BSS and GT are rare inherited platelet disorders characterized by defects in platelet glycoproteins, leading to bleeding complications 2, 3, 4.
- The main difference between the two disorders lies in the specific platelet glycoproteins affected: GT is caused by a defect in the GPIIb/IIIa complex, while BSS is caused by a defect in the GPIb-IX-V complex 4.
Clinical Features and Management
- Patients with both BSS and GT often experience mucocutaneous bleeding, leading to anemia and transfusion requirements 5.
- Management of BSS and GT focuses on prophylactic treatment prior to high-risk procedures and treatment in response to non-surgical bleeding events 3.
- Platelet transfusion is frequently needed for controlling spontaneous bleeding and is always needed when trauma occurs or surgery is performed, but it carries a risk of alloimmunization against HLA antigens and/or platelet glycoproteins 2, 4.
- Alternative treatments include antifibrinolytic agents, desmopressin, recombinant factor VIIa, and female hormones 2, 4, 6.
Complications and Associated Conditions
- Iron deficiency anemia is a common complication of recurrent bleeding events in patients with BSS and GT, and routine monitoring for iron deficiency may help improve bleeding management and reduce bleed burden 6.
- Alloimmunization against platelet glycoproteins can occur in patients with BSS and GT, leading to refractoriness to platelet transfusion therapy 4.
- Pregnancy and menorrhagia can be challenging to manage in patients with BSS and GT, and may require specialized care and treatment 2, 3.