Inherited Clotting Deficiency in Cats

Some conditions limit the amount of platelets available in the bloodstream. Others damage the platelets so they are unable to stick together properly to form the blood clot. These inherited defects can turn a minor cut into a life-threatening event, depending on how severe they are. The most extreme cases of these congenital issues may result in kittens being stillborn or dying shortly after birth from internal blood loss. Other kittens may bleed abnormal amounts during regular teething. A veterinary assessment will provide recommendations for treatment and care of a cat with an inherited clotting deficiency.

When a cat's blood and cells are functioning properly, the body has a process to handle bleeding (which is caused by the breaking of blood vessels). Affected blood vessels should constrict to slow down the blood flow and reduce the amount of blood lost. Platelets in the blood then flock to the injury site and change their composition from a round to a more spiked shape. This allows the platelets to stick to each other and to the damaged blood vessel. A protein found in the blood then creates “fibrin” tissue, which form long strands that create a net-like effect and trap the conjoined platelets. This response is called “clotting”. If there are any genetic conditions present that hinder the platelets, proteins, or response system in the cat, clotting does not occur properly and the cat can bleed out.

In less severe cases, the problem may not come to light until the cat experiences surgery or major trauma. Sometimes the condition is hard to discover because the bleeding is happening internally or in a location that isn't obvious. Signs to watch for include:

• Delayed bleeding
• Nosebleeds
• Small bruises
• Easy bruising
• Hematomas (deep bruises)
• Spontaneous bleeding
• Prolonged bleeding after a vaccination
• Excessive bleeding while teething
• Black or bloody feces
• Joint bleeding
• Loose, delicate, or stretchy skin
• Pale coat color
• Pale gums
• Lameness

There are a number of genetic conditions that can be passed down that interfere with the clotting process. It seems that the gene code areas responsible for plasma proteins, other proteins and for communication between the cells can mutate and then become hereditary issues. All known conditions are listed below.

Hemophilia A

This is the most common genetic clotting defect in cats. It is generally not as severe as others, and may not be noticed until the cat is older than 6 months of age.

Hemophilia B

This condition is rare and is extremely severe. Many kittens with this defect will die in utero. Most kittens that are born with this problem will be diagnosed shortly after birth as they may spontaneously bleed. Cat breeds that are more susceptible to this condition include Himalayans, Siamese and British Shorthairs. 

Von Willebrand's Disease

This inherited clotting defect is not common in cats. Affected cats may have defective clotting proteins in their bloodstream, or be missing them entirely.

Chediak-Higashi Syndrome

This syndrome is a very rare genetic form of albinism that also leads to mild clotting issues.

The first indication of a genetic clotting problem may make itself known when the cat receives its first vaccinations or undergoes a neutering surgery. In cats that are showing symptoms before this, be prepared to provide the cat's full medical history to the veterinarian, and to answer questions about any and all bleeding the cat has experienced. A complete physical examination will be performed and all bruising will be noted. Blood work in cats with inherited clotting deficiencies will reveal much about the severity of the condition. A complete blood count will show any abnormal white blood cell levels, determine how anemic the cat is and show how many platelets are present in the bloodstream.

A test known as a “buccal mucosal bleeding time” (BMBT) may be used to determine platelet function. A small cut is made on the gums, and then the time it takes for the body to stop the bleeding is recorded. Times longer than 4 minutes suggest clotting issues exist. Blood samples may be taken and then artificially stimulated to clot. Certain tests exist to determine clotting abnormalities such as an activated coagulation time (ACT) test, an activated partial thromboplastin time (aPTT) test or a one stage prothrombin time (OSPT) test. Tests may also be run to check for Willebrand's factor or a concentration of soluble coagulation factors in the blood.

Congenital clotting defects are generally not curable, however, their severity can be lessened in some cases. The appropriate course of treatment will depend on the condition that has been diagnosed. Gauze may need to be packed at the bleeding site prior to treatment to slow bleeding. 

Hemophilia A 

The most common procedure for treating this defect is repeated whole blood or plasma transfusions. Hospitalization is required for blood transfusions. They will need to be continued until the cat stops bleeding.

Hemophilia B 

Fresh or fresh frozen plasma transfusions may be used to treat a cat with this deficiency who is bleeding. 

Von Willebrand's Disease 

A combination of plasma transfusions and certain medications that increase the Willebrand's factor in the blood may be used to treat this disease.

Chediak-Higashi Syndrome 

This syndrome is generally not treatable. Bone marrow transplants and prescription medications have shown some promise in alleviating the severity of the syndrome.

After the cat has been treated for an episode of bleeding, continue to monitor it for cuts or wounds on the body. Administer all medications as prescribed by the veterinarian. Many cats with inherited clotting deficiencies will have a high risk of bleeding out from injuries for the rest of their lives. It may help to keep affected cats indoors to limit the possibility of traumatic injuries. 

Invasive veterinary procedures should be avoided in cats with clotting defects. There are also many medications that should not be given to affected cats, such as heparin, dextran and nonsteroidal antiinflammatory drugs (NSAIDs). The parents and siblings of the cat should also be tested to determine which cats are carriers and which cats have the genetic defect. All related cats should not be bred. There are varying severities of clotting deficiencies. Mild cases often result in a normal life for the cat as long as certain precautions are taken.