How does von Willebrand's disease (VWD) differ from Bernard-Soulier syndrome? Correlate the pathophysiology of both disorders in your response. Name at least two laboratory tests that differentiate each
What will be an ideal response?
Answer: von Willebrand's disease results from a deficiency in VWF, which has several essential functions in coagulation as (a) carrier protein for factor VIII: C and (b) interaction of platelet glycoprotein Ib/IX to subendothelial collagen that results in platelet adhesion. As a result of this, VWD patients exhibit signs of primary hemostatic pathway anomalies, which include mucocutaneous systemic bleeding and petechiae.
Bernard-Soulier syndrome is an inherited qualitative disorder that results in a defective glycoprotein Ib/IX receptor. As a result, the BSS patient exhibits signs of primary hemostatic pathway anomalies, much like with VWD. From a clinical standpoint, VWD and BSS appear very similar.
In regard to the screening tests, both disorders yield similar results. Standard screen for primary hemostatic anomalies is abnormal in both cases.
The main difference between the two is in multimer analysis and factor VIII: C levels. Because VWF is needed as a carrier protein for factor VIII: C, a patient with VWD will show decreased activity with factor VIII: C. Conversely, BSS will show normal levels. In addition, multimer analysis will be abnormal (because it assesses VWF multimers) in most cases of VWD, whereas in BSS, it will be normal.