Von Willebrand disease — branching viva

Examiner opening (Examiner)

You are the general paediatric registrar in the outpatient clinic. A fourteen-year-old girl is referred with heavy menstrual bleeding that has caused iron deficiency anaemia, lifelong easy bruising, and prolonged epistaxis. Her platelet count is normal and her activated partial thromboplastin time is mildly prolonged. Talk me through your assessment and diagnostic plan. [1]

Exemplar opening (Candidate)

This girl's presentation is the classic picture of von Willebrand disease, the most common inherited bleeding disorder. Heavy menstrual bleeding severe enough to cause iron deficiency, lifelong easy bruising and prolonged epistaxis, with a normal platelet count and a normal or mildly prolonged activated partial thromboplastin time, together point to a defect of primary haemostasis rather than a clotting-factor deficiency. I will confirm the diagnosis with the von Willebrand factor panel: von Willebrand factor antigen for quantity, von Willebrand factor activity for function (ristocetin cofactor activity or a newer glycoprotein Ib-binding assay), and factor VIII activity. Because von Willebrand factor levels fluctuate and blood group O lowers the level by about 25 to 30 percent, I will repeat the panel if the first result is borderline and the bleeding history is convincing. I will take a structured bleeding history with a bleeding assessment tool and a three-generation family history, because the inheritance is usually autosomal dominant. [1] [2]