What is Hemophilia?
Hemophilia can often be seen in puppies, who can exhibit prolonged bleeding and even die within weeks after birth. Dogs that are less severely affected can survive into adulthood, but will have intermittent episodes of bleeding. The severity of the condition depends on the degree of the coagulation deficiency. Hemophilia is more commonly seen in purebred dogs, and occurs more often in the males.
Hemophilia is an inherited disorder involving a deficiency of the clotting activity in the blood. Hemophiliac dogs suffer from spontaneous and prolonged bleeding from various areas, such as trauma sites, umbilical cords after birth, and the nose, mouth and eyes. Internal bleeding in body cavities such as the chest or abdomen can cause swelling that can lead to death.
Symptoms of Hemophilia in Dogs
Dogs affected with hemophilia can suffer spontaneous episodes of bleeding that are often quite prolonged. They can also exhibit prolonged bleeding after surgery. Spontaneous bleeding into joints and muscles can lead to swelling and lameness, while the acute blood loss can result in hypovolaemic shock. Symptoms you may see in your dog include:
- Sudden death within the first few weeks of life
- Prolonged bleeding from umbilical vessels
- Spontaneous bleeding
- Bleeding from mouth, particularly during the growth of adult teeth in puppies
- Skin hematomas, or a swelling composed of clotted blood
- Excessive and prolonged bleeding at any trauma or surgery site
- Bleeding into joints or body cavities
- Swelling in joints or muscles
- Red, round, pinpoint spots appearing on skin
- Discolored skin
- Nose bleeds
- Blood collecting inside the eye, covering the iris and pupil
- Partial or complete loss of vision
- Dark and sticky feces containing blood
There are two types of hemophilia seen in dogs.
- Hemophilia A is a deficiency of coagulation factor VIII, and is the most common inherited clotting disorder in dogs. It can affect most dog breeds
- Hemophilia B is a deficiency of coagulation factor IX. This type is rarer than hemophilia A, and has been known to affect over 25 breeds of dogs
Causes of Hemophilia in Dogs
Hemophilia results from a deficiency of the coagulation Factors VIII and IX. These genes are responsible for the normal blood clotting activity that stops the body from bleeding out. When a mutation or abnormality occurs in these genes, it can disrupt the coagulation process, preventing blood clotting and resulting in uncontrolled bleeding.
This deficiency comes about from a spontaneous gene mutation that can be transmitted through generations. This sex-linked recessive gene is carried on the X chromosome, which means that it is transmitted by the females, who are often asymptomatic carriers. Male puppies born to an affected dam have a 50% chance of developing hemophilia, while the female puppies carry a 50% chance of becoming carriers.
Diagnosis of Hemophilia in Dogs
Hemophilia is often noticed in dogs after routine surgery if post-operative bleeding becomes excessive or prolonged. A diagnosis will depend on the specific symptoms, the results of testing, and possibly, a pedigree analysis.
Testing includes performing coagulation assays on blood samples. Tests such as an APTT, or activated partial thromboplastin time, can detect a clotting disorder, but cannot diagnose the particular type of hemophilia present. Measuring a different blood protein or the activity of Factor VIII can help to determine the type of hemophilia your dog may have. The levels of Factor IX can also be measured in the blood.
Treatment of Hemophilia in Dogs
There is no cure for hemophilia. The main method of treatment for bleeding episodes in dogs involves repeated substitution therapy. This means intravenous whole blood or plasma transfusions until the bleeding can be controlled. Whole blood transfusions are generally given to more severe cases involving life-threatening anemia. Your dog may also be given blood products containing clotting factors. Gene therapy that uses adeno-associated viral vectors may also be a possible treatment.
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Recovery of Hemophilia in Dogs
Recovery for puppies who show signs of hemophilia can be poor, as many experience internal bleeding early on that can be lethal. In older dogs, the bleeding can be excessive, and if left untreated, can also be fatal. If your dog has a less severe case, he may experience intermittent bleeding episodes throughout his lifetime that need to be promptly treated before too much blood loss has occurred.
Prevention of this inherited gene dysfunction is through selective breeding by excluding affected dogs. Once hemophilia is diagnosed in a puppy, it can alert you to the presence of the gene in the mother. Whether she is an asymptomatic carrier or shows signs of the condition, she should not be bred further, nor should any females born of male carriers. Keeping updated pedigree records can help stop the further spread of this mutation.