You may have never heard of Von Willebrand’s Disease in dogs but it is the most common bleeding disorder in dogs. It's inherited and similar to hemophilia whereby the dog's blood is unable to clot due to a deficiency of a protein called von Willebrand factor (vWf).
There are three types; I,II, & III with the most common and least severe being Type I. It's been diagnosed in up to 50 breeds and is often not discovered until a bleeding event occurs such as surgery, a nose bleed, nail clipping, excessive bleeding during heat cycles, etc,.
Von Willebrand’s Disease
Von Willebrand’s disease, often referred to as Von Willebrand disease, von Willebrand's Disease, VWD, and vWD, is the most common blood clotting disorder found in domestic dogs. The condition is caused by a deficiency in the production of Von Willebrand’s factor, a necessary component in the blood clotting process. Von Willebrand’s Disease is named for the Finnish pediatrician Dr. Erik Von Willebrand, who first identified the disease in 1924 after working with a number of affected families in the Aland Islands. Von Willebrand’s disease is one of the few conditions caused by genetic mutations which are nearly identical across multiple species, and is not only the most common blood clotting disorder in domestic dogs but also in human beings. In fact, research into Von Willebrand’s disease in human beings has greatly influenced understanding of the disease in dogs and vice versa.
Blood is one of the most important parts of the canine body. The fluid carries oxygen and nutrients throughout the entire body, and can be thought of as a highway providing the body with what it needs to function. In order to constantly supply the body, blood must constantly flow through the circulatory system. Were it not for blood clotting, this would mean that if a part of the circulatory system is punctured or severed blood would continue to flow out of that break until the dog died from blood loss. Luckily, the blood clotting system exists to prevent exactly that. Blood clotting is a very complex process that is designed to stop the blood from flowing out of an injury to the circulatory system. In very simple terms, tiny cells known as platelets travel through the blood stream waiting for an injury to occur. When an injury is located, the platelets become, “sticky,” or “activated.” They then adhere to the walls of the circulatory system and to each other, forming a, “wall,” known as a, “white clot.” At the same time, a number of free moving proteins and other molecules are also traveling through the blood stream, molecules which form the thrombin system. When bleeding occurs, these molecules activate. Once activated, these molecules begin to form long strands known as fibrin. Fibrin strands stick to the circulatory system’s walls to form a web-like structure. Fibrin webs begin to, “catch,” red blood cells and stick them together, forming a, “red clot.” The fibrin webs also strengthen the, “white clots,” formed by platelets and join them to, “red clots.” The combination of “white clots” and “red clots” forms what is known as a mature clot. Mature clots form a, “wall,” which more blood cannot flow through, therefore protecting the body from additional blood loss.
Von Willebrand’s factor is one of the many proteins involved in the blood clotting process. In normal dogs….