Written by Dr Mirjam van der Wel, Principal Veterinarian at Vets Incorporated, Westering
Blood clotting is essential for survival.
When a blood vessel gets broken, a whole cascade of events take place to stop the bleeding (this is known as haemostasis).
The blood vessel constricts to slow down the blood and a number of proteins (also known as blood clotting factors) start the finely orchestrated process of creating a blood clot. With the help of these proteins, platelets change shape so they can stick to each other, the blood cells and to the wall of the broken blood vessel. Other proteins make fibrin strands which form a net to hold the platelets and the blood cells together as a clot, which in turn plugs the hole in the vessel and stops the bleeding.
Once the clot is stable, other proteins stop the clotting process and finally dissolve the clot.
Haemophilia is the most common inherited blood clotting deficiency in dogs.
Haemophilia A is a deficiency of clotting factor VIII, haemophilia B (less common) of factor IX.
Haemophilia is linked to the X chromosome.
Males have only one X chromosome (XY), so they either have haemophilia or they don’t.
Females have two X chromosomes (XX). They can be clear (normal genes on both X chromosomes), a carrier with no symptoms (abnormal gene on just one of the X chromosomes), or affected when there’s an abnormal gene on both X chromosomes.
Practically speaking, the disease is carried by females but mostly affects the males.
The disease is seen in various breeds of dogs (most commonly in the German Shepherd) and also in mixed breed dogs.
Dogs may show the effects of haemophilia in varying degrees, depending on how much of the clotting factor the body produces.
Affected dogs may show some of the following symptoms:
-
Prolonged bleeding from the umbilical cord
-
Excessive bleeding from the gums when the dog is teething
-
Excessive bleeding after injury or surgery (e.g. spaying/castrating)
-
Lameness due to bleeding in a joint or swelling caused by bleeding into muscles
-
Internal bleeding into abdomen, chest or central nervous system and organ bleeding
-
Bloody urine or stool
-
Easy bruising
These symptoms are suggestive of a bleeding disorder (and that’s not just haemophilia) and your vet will need to run further tests to determine what’s going on.
There’s no cure for haemophilia and the symptoms will need to be managed.
Mild cases may only need treatment after injuries or surgery.
The more severely affected dogs will need regular transfusions of blood and blood products and a lifestyle that prevents trauma.
Due to the debilitating nature of haemophilia, affected animals are often euthanised.
Breeding with haemophiliac dogs (including the carriers) should be avoided.
Always consult with your veterinarian if your pet seems unwell.
