Taking a minute to stop and think about how many functions our blood performs is truly amazing. It transports hormones, warmth, building materials, energy particles and oxygen around the body. The fluid or plasma portion of blood carries the ability to form instant plugs should the need arise when a blood vessel gets injured. To accomplish this, a cascade of reactions involving several types of particles called factors and specialized blood cells called platelets is necessary. This system is complex and sometimes does not function quite up to par. Many different types of bleeding disorders are known. The most common type affects about 1% of the general population and is termed von Willebrand Disease (vWD). Persons with this disease tend to bleed more than normal. Slow stopping nose bleeds, spontaneous bruising and long menstrual periods are often attributed to this affliction. It is now recognized to be a hereditary problem affecting proper platelet functioning with at least four sub-types. The disease is a genetically dominant one, meaning that only one gene is necessary to show clinical symptoms. There is a 25% chance that it will be passed on to an offspring.
When you injure a blood vessel, a special protein called the von Willebrand Factor (vWF) accumulates by the break and attracts sticky platelets into the vicinity. These platelets attract long fibrin strands into the area forming a clot. Von Willebrand Disease results when the body does not produce enough vWF, does not metabolize it quickly, or when it produces a defective type of vWF. For the most part, the disease is not severe and is only of significance during times of intense bleeding such as major trauma, surgery or childbirth. Diagnosis begins with a laboratory test called a Bleeding Time. There are drugs which can increase the levels of vWF if the need arises, but should not be used regularly. Aspirin and various anti-inflammatory medications or herbs should be avoided by afflicted individuals.
There are other more serious but rarer types of bleeding disorders. Hemophilia A is a very similar genetic condition in which the body fails to produce sufficient Factor VIII, and prolonged bleeding results. To respond quickly and efficiently to a host of different situations, the human body evolved to develop elaborate methods to control bleeding and injury. This relies on the production and interaction of about a dozen different proteins called clotting factors. Hemophilia B, commonly known as Christmas Disease, is another condition attributed to a deficiency in Factor IX.
The standard treatment for Von Willebrand Disease is to simply avoid things like aspirin which make it worse. Hemophilia on the other hand requires regular top-ups of the deficient factors. What is really exciting is the advent of gene therapy. Now that we know where the genes are that produce these factors, it is possible to infiltrate the cells that produce clotting factors with laboratory made copies of the proper gene and induce them to manufacture the missing factors naturally. As in all things Canadian, it just has not quite been made practical yet.
● Von Willebrand Disease from eMedicine, article by John D Geil, MD, University of Kentucky Children's Hospital.
● von Willebrand Disease from KidsHealth.
● Von Willebrand's Disease from MedlinePlus Medical Encyclopedia, with illustrations of blood clots.
● von Willebrand Disease Information Sheet from OBGYN.net (Obstetrics, Gynecology, Infertility and Women's Health) - Brief History, FAQ.
● What Is a Bleeding Disorder?
Types of Bleeding Disorder - Hemophilia A (Factor VIII Deficiency)
● Hemophilia B (Factor IX Deficiency)
● von Willebrand Disease - What Is It? from Hemophilia.org Bleeding Disorders Information Center.
● What is von Willebrand's disease? Von Willebrand's disease (vWD) is a common, usually mild, inherited bleeding disorder in people and in dogs. From Canine Inherited Disorders Database.