von Willebrand's disease (VWD)
Last updated: Thursday, 20, January, 2011
|Key Information||Appropriate Tests|
The diagnosis is usually considered because of a personal and/or family history of easy bruising or bleeding. Normal results on initial testing (FBC, APTT) do not exclude VWD.
The diagnosis is established on the basis of assays of factor VIII, von Willebrand factor (VWF), collagen binding assay, ristocetin cofactor and possibly other assays.
In females, blood should be collected during menstruation, normal results mid-cycle or during pregnancy do not exclude the diagnosis.
Studies should be repeated on 2-4 occasions if clinical suspicion is high or if a previous diagnosis of VWD is to be refuted.
von Willebrand's disease type 1
|Quantitative deficiency of VWF (functional and antigen assays). Most respond to DDAVP.|
von Willebrand's disease type 2
'Variant' VWD: a heterogeneous group of disorders including those with absence of multimeric forms of VWF, and those in which VWF has an increased affinity for the platelet receptor.
Some variants (2B) develop thrombocytopenia with desmopressin which should be avoided. Also includes the VWD 2N (Normandy) variant which presents like, and may provide an alternative diagnosis to, haemophilia A.
von Willebrand's disease type 3
|Rare and is associated with a severe deficiency of VWF.|
Pseudo von Willebrand's disease
A disorder of platelets, characterised by increased affinity for VWF.
There is a risk of increasing thrombocytopenia with either desmopressin or cryoprecipitate/factor VIII infusion, which should be avoided.
Acquired von Willebrand's disease especially
|Variable reduction in factor VIII, VWFAg, VWF (functional) assays.|