<prompt> Which of the following is true regarding Von Willebrand disease?Type 1 3 are associated with quantitative defects in vWFNormal platelet countDesmopressin stimulates release of VWFAll of the above.  <response>: Ref. Robbins Pathology. 9th edition. Page. 667 Von Willebrands factor is a glycoprotein made in epithelial cells and megakaryocytes which:Acts as a bridging molecule between platelets and the sub-endotheliumHelps platelets bind to each otherIs a carrier of factor VIII, helping to prevent its breakdown in the circulation Types of Von Willebrands disease:Type 1Decreased quantity of VWF Mild to moderate bleedingType 2 several subtypes exist Qualitative defect - abnormal types of VWF Type 3 Trace of VWFAutosomal recessive Severe bleeding disorderPresentation includesProlonged bleeding after injury Easy bruisingProlonged epistaxis Menorrhagia Oral bleeding eg after tooth extraction Investigation VWF antigen levelAt least 2 occasions Will be low or normal in Von Willebrands disease Note it is elevated by exercise and hyperthyroidismIt is decreased by hypothyroidism Von Willebrand factor ristocetin cofactor activityPT, platelet count and fibrinogen levels are usually normalaPPT usually prolongedTreatment Desmopressin DDAVP Increases factor VIII and VWF Useful in type 1, variably useful in type 2, not useful in type 3Tranexamic acid An antifibrinolytic agent Useful in management of epistaxis and menorrhagia Avoid in patients with history of thromboembolic disease or current upper urinary tract bleedingVWFfactor VIII concentrate 