Bleeding Disorders - von Willebrand Disease

It’s been too long since I have done a blog and I feel it is well needed. Today I will talk about another bleeding disorder that the Haemophilia Society support sufferers of, Von Willebrand Disease (VWD). This is a disorder caused by missing or defective von Willebrand Factor (VWF). VWF is a clotting protein that binds factor VIII (previously mentioned in relation to Haemophilia A) and platelets in the blood vessel walls to plug a cut or abrasion.

You can think of blood clots like composite materials (steel-reinforced concrete, glass-fibre, cardon-fibre, etc.), to make a strong material you need both parts, but if one is missing or there is a lack of one, you will not get a final product that can complete the task required. In blood terms, Factor VIII is the steel bars/fibres that provide the strength to the clot and VWF is the concrete/resin required to hold the fibres together and stick to the blood vessel walls.

VWD affects up to 1% of the US population and is carried on chromosome 12 and occurs equally between genders. The symptoms/side effects of being deficient in VWF is similar to other bleeding disorders. These include nosebleeds, easy bruising and excessive bleeding during and after invasive procedures such as surgery or tooth extractions. Women will have additional complications with heavy menstrual periods that last longer than normal and hemorrhaging after childbirth.

There are four types of VWD. The main three are based on qualitative or quantitative defects in VWF but there is a fourth type, acquired VWD, which is not hereditary. Typically the plasma of patients with VWD typically have least than 50% of normal VWF.

DDAVP (Desmopressin Acetate) that is used as a treatment for Haemophiliacs is also used for sufferers of VWD. This is because it raises levels of both VWF and Factor VIII. This does act as an antidiuretic though causing the body to retain water. This means the fluid restrictions are placed on the patient for the 24 hours post treatment. Tranexamic acid is also a treatment for both disorders as it prevents the breakdown blood clots.

There are a few clotting factor concentrates that are rich in VWF and are recommended for patients with VWD and are given via intravenous infusion. Back in December, the US Food and Drug Administration (FDA) approved the first recombinant VWF product that contains only VWF, not including Factor VIII. This medication, Baxalta’s Vonvendi, is approved to treat on-demand and for control of bleeding in adults 18 and over.

I hope you, like myself, have learnt something from this post. I hadn’t really known too much regarding this disorder, the types, treatment or that it can be acquired.

Until next time!