Von Willebrand disease is an inherited condition that leads to increased bleeding times. In the event of trauma, it is important that the doctor knows when a patient has Von Willebrand disease. For this reason, many patients wear bracelets engraved with "Von Willebrand Disease" to alert the doctor to their condition.
Initial Blood Clotting
When a blood vessel is ruptured, the vessel wall undergoes several changes to respond to bleeding. The vessel wall contracts and several chemicals are released that encourage blood clotting to stop the bleed. Among the changes that take place, platelets change shape and stick together to form a clot, stopping minor bleeds. An important chemical is Von Willebrand Factor, which is released into injured vessels and enables platelets to stick together. Without this chemical, the initial blood clot does not form and minor bleeding continues.
Further Clotting
Chemicals in the blood react to form a more stable clot. These chemicals are known as factors, and they activate each other in a cascade of reactions, resulting in a stable clot. One of the key factors is factor VIII, which is transported by Von Willebrand Factor. If Von Willebrand Factor is defective, as in the case of Von Willebrand Disease, the cascade of reactions is halted and a clot may take a long time to form or may not form at all.
Von Willebrand Disease
Von Willebrand Disease, or VWD, was discovered by Erik von Willebrand in 1924 and is an inherited genetic condition, the most common inherited bleeding disorder. It is caused by a mutation on chromosome 12; therefore, unlike hemophilia, it affects both sexes. The gene causing VWD is dominant, meaning only one parent with the faulty gene passes on the condition. There are three variants of VWD, type one being the most common and type three being the most serious. Patients with VWD experience extended bleeding times particularly after surgery, and often suffer from frequent nose bleeds and bruising. Females often suffer from heavy periods.
Treatment
For the majority of cases, no treatment is administered for VWD. However, sometimes VWD can be treated with desmopressin. This increases clotting by releasing clotting factors into the blood stream and by constricting blood vessels. In his review of drug therapy for Von Willebrand Disease in the New England Journal of Medicine, Pier Mannucci reports that patients with type 1 VWD are more likely to be responsive to desmopressin than other types of VWD. In their textbook of clinical medicine, Kumar and Clarke write about factor VIII concentrates containing Von Willebrand Factor and so can be given to patients with severe bleeding. Patients who cannot be given desmopressin may be given cryoprecipitate, which is plasma containing high concentrations of factor VIII and VWF. This is not frequently given, since viruses cannot be inactivated in this treatment.
Bracelet for Von Willebrand Disease
Patients with Von Willebrand Disease may decide to wear a bracelet which in the circumstance of an accident will alert a health-care provider to their condition. This ensures awareness of the increased danger of excessive bleeding. Often, patients will have "Von Willebrand Disease" engraved on the bracelet.
References
- Kumar and Clark's Clinical Medicine 7; "Haematological Disease"; Parveen Kumar, Michael Clarke; 2009
- "The New England Journal of Medicine"; Treatment of Von Willebrand’s Disease; Pier Mannucci; Augus 12 2004
