BOF: Clotting (Haemophilia)
- Aug 8, 2016
- 2 min read
A 60 year old woman was diagnosed with chronic lymphocytic leukaemia 18 months ago, stage A/0 with no treatment required and very well on active monitoring. She is admitted with easy bruising and prolonged epistaxis with no clear bleeding point. Bloods reveal a mild anaemia with haemoglobin 10.9 gdl⁻¹, normal platelet count and neutrophil count with a lymphocytosis of 24x10⁹/ L⁻¹, positive direct antiglobulin test (IgG and complement), LDH 800 iu L⁻¹ and total bilirubin 34 umol L⁻¹. Which ONE of the following would BEST support the diagnosis of acquired von Willebrand’s disease as a cause of her bleeding?
a) Family history of von Willebrand’s disease.
b) Long history of easy bruising and and menorrhagia prior to the menopause.
c) Normal APTT.
d) VWF:Ag - <0.1 UdL⁻¹
e) VWF:RiCof - 25 UdL⁻¹ not corrected by the addition of normal plasma.
Answer:
e) VWF:RiCof - 25 UdL⁻¹ not corrected by the addition of normal plasma.
Explanation:
Acquired von Willebrand’s disease (VWD) is caused by dysfunction or loss of von Willebrand’s factor in a patient with no personal or family history of VWD or bleeding disorder. It may be caused by reduced synthesis, increased destruction (immune or mechanically mediated), increased proteolysis or adsorption onto VWF receptor bearing malignant cells. As such it is associated with drugs, lympho and myeloproliferative diseases including MGUS, non-haematological malignancy, autoimmune diseases, angiodysplasia or structural cardiac defects. Mixing studies can reveal the presence of an inhibitor (as in this case) but are unreliable unless they involve the Gp1b receptor interaction, and in the presence of a suggestive personal or family history of bleeding, von Willebrand’s screening tests will not differentiate acquired from congenital except with profoundly low values suggesting congenital defects
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