Hereditary And Acquired Disorders Of Blood Clotting Factors In Dogs

The clotting process involves a lot of different proteins; therefore deficiencies in any of these proteins can result in bleeding abnormalities. The symptoms of severe deficiency of clotting factors or  proteins usually appear early in life, with some animals being stillborn or dying immediately after birth. Actually, most congenital clotting disorders are due to a defective single protein. Newly born animals that are deficient in clotting proteins or vitamin K may suffer due to it. The presence of even 5 to 10% of normal clotting proteins is enough to ensure the survival of a newborn, though it will usually display symptoms of illness before 6 months of age. This period of life is typically when most routine procedures are done e.g. inoculation and dewclaw removal, thus providing an opportunity for your veterinarian to detect any bleeding disorders.

Hypofibrinogenemia, which isan abnormal lack of fibrinogen in the blood, is commonly seen in Saint Bernard and Vizslas breeds. Dysfibrinogenemia, which is a condition related to abnormally functioning fibrinogen, has been noted in an inbred family of Russian Wolfhounds (Borzois). Dogs suffering from the disorder experienced mild bleeding problems like nosebleeds, but any kind of injury or surgery ended in fatal bleeding. The most effective way of stopping the bleeding is to give an intravenous transfusion with fresh or fresh-frozen plasma.

Factor II (prothrombin) disorders are quite uncommon. Prothrombin is a protein that is used in the blood clotting process. Although Boxer dog breeds are said to have normal levels of prothrombin in the body, the protein does perform its functions as required. English Cocker Spaniels are also said to have a Factor II disorder. As an animal becomes older, the symptoms of the disorder, like nosebleeds and bleeding gums, dissipate. However, symptoms like easy bruising and inflamed skin become more prevalent in adults. The treatment available includes transfusion of whole blood or plasma.

Deficiency of Factor VII, another clotting protein, is a condition that affects Miniature Schnauzers, Beagles, English Bulldogs, Boxers, Alaskan Malamutes and dogs of a mixed breed. It is typically not related to abrupt, unexplained bleeding, but dogs affected by it may experience bruising or disproportionate loss of blood following surgery. This particular deficiency is usually inadvertently diagnosed when clotting tests are conducted.

Haemophilia A (Factor VIII deficiency) is by far the most widespread hereditary bleeding disorder in dogs. It is the female of the species that carries the gene for the disease, yet doesn’t show any symptoms, with the males not being so lucky.Puppies that suffer from haemophilia A experience sustained bleeding from the umbilical cord after they are born, bleeding from the gums during teething, and following surgical procedures. Small dogs are also unlikely to display symptoms of illness. Dogs that have less than 5% of normal Factor VIII activity generally display symptoms such as inability to walk due to bleeding joints, inexplicable clot formation, and internal bleeding. On average, those with 5 to 10% of normal activity rarely bleed unexpectedly, although they bleed exceptionally following an injury or surgery. Animals that carry the defective gene tend to have higher levels of Factor VIII (40 to 60% of normal), with clotting tests bringing back normal results. It is more difficult to diagnose animals younger than 6 months of age because their livers haven’t yet generated adequate clotting proteins. Continual transfusion of whole blood or plasma is the common treatment prescribed, and is done until bleeding has been controlled.

Haemophilia B (Factor IX deficiency) is more rare than haemophilia A, and has been discovered in a number of purebred dogs and a mixed-breed dog. Though the female of the species usually carries the disease, it hardly ever shows any signs, which happen to be similar to those of haemophilia A. In fact, some animals show no symptoms until after an injury crisis or surgery. Such situations result in internal bleeding inside the abdomen, the central nervous system, the chest, and muscles. Animals with exceptionally low Factor IX activity i.e. lower than 1% of the norm, typically don’t live very long after birth. Animals having 5 to 10% of normal Factor IX activity may unexpectedly develop blood clots, bleeding in the joints and the body cavity, bleeding gums during teething, or organ bleeding. No symptoms are displayed by carriers with 40 to 60% of normal Factor IX activity, and they give normal results on blood clotting tests. Management of the disease involves transfusion with fresh or fresh-frozen plasma. Though rare, there have been few cases of hereditary clotting protein abnormalities in dogs. These notable cases involved severe deficits in Prekallikrein, Factor X, Factor XI, and Factor XII.

Acquired Disorders Of Clotting Protein (Factors) In Dogs

Since a majority of clotting proteins are manufactured in the liver, any disease that affects the liver can cause diminished levels of clotting proteins, especially Factors VII, IX, X, and XI. Severe liver disease can bring about a condition known as disseminated intravascular coagulation. Liver disease causes elevated levels of fibrinogen and von Willebrand’s factor. Fibrinogen is a blood protein made in the liver and transformed to fibrin in reaction to tissue damage, while von Willebrand’s factor is created outside the liver and facilitates platelets attach to the blood vessel wall and to each other.

Dogs that consume rat poison may develop problems with blood clotting, due to the liver’s reduced production of clotting proteins. It is not common for the affected animals to bleed within the first 24 hours, but may develop blood clots and bruising of surface and deep tissues. Injections and oral doses of Vitamin K are the prescribed treatment, although they may result in side effects like anaemia or allergic reactions. An urgent trip to the veterinarian is recommended if there is any suspicion that your dog has ingested any kind of rat or mouse poison.

Disseminated intravascular coagulation (DIC) is a condition where tiny blood clots develop all over the bloodstream, jamming small blood vessels and damaging the platelets and clotting factors essential for bleeding control. It is usually triggered by severe infections, heat stroke, burns, tumours, or extreme injury. In most cases, the symptoms appear like uncontrolled bleeding and the failure to form a normal clot. Death results from extensive blood clots and collapse of circulation, leading to organ failure. Unfortunately, a persistent type of DIC develops if the animal survives this situation. Your veterinarian will establish and try to rectify the core problem causing this condition. DIC can be fatal, so it’s important to administer intravenous fluids in order to maintain normal circulation.

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