von Willebrand Disease

Published on 22/03/2015 by admin

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Last modified 22/03/2015

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Chapter 471 von Willebrand Disease

The most common hereditary bleeding disorder is von Willebrand disease (VWD), and some reports suggest that it is present in 1-2% of the general population. VWD is inherited autosomally, but most centers report more affected women than men. Because menorrhagia is a major symptom, women may be more likely to seek treatment and thus to be diagnosed. VWD is classified on the basis of whether the protein is quantitatively reduced, but not absent (type 1); qualitatively abnormal (type 2); or absent (type 3) (Fig. 471-1). Mutations in different loci that code for different functional domains of the von Willebrand factor (VWF) protein cause the different variants of VWD.

Clinical Manifestations

Patients with VWD usually have symptoms of mucocutaneous hemorrhage, including excessive bruising, epistaxis, menorrhagia, and postoperative hemorrhage, particularly after mucosal surgery, such as tonsillectomy or wisdom tooth extraction. Because a teenager’s menstrual history is usually put in the context of other family members, excessive menstrual bleeding is not always recognized as being abnormal, because others in the family may be affected with the same disorder. If a menstruating female has iron deficiency, a detailed history of bruising and other bleeding symptoms should be elicited and further hemostatic evaluation undertaken.

Because VWF is an acute-phase protein, stress will increase its level. Thus, patients may not bleed with procedures that incur major stress, such as appendectomy and childbirth, but may bleed excessively at the time of cosmetic or mucosal surgery. Bruising symptoms may diminish during pregnancy, because VWF levels may physiologically double or triple as an acute phase response. Rarely, patients with VWD may have gastrointestinal telangiectasia. This combination results in major bleeding and accounts for numerous hospital admissions for patients with severe disease. In patients with type 3, or homozygous, VWD, bleeding symptoms are much more profound. These patients are usually diagnosed early in life and may have severe epistaxis or menorrhagia that results in major blood loss and possibly shock. Patients with severe type 3 VWD may have joint hemorrhages or spontaneous central nervous system hemorrhages.