Clotting Disorders of the Platelets in Dogs

In a bleeding disorder, platelets may not respond as they should in the clotting process. For an example, the immune system can mistakenly destroy platelets, or platelets may not separate as they should. Other disorders result in an abnormally low number of platelets, or a failure to clot. When there is a severe clotting problem, canines with this issue will have excessive bruising, uncontrollable bleeding and other symptoms that can lead to life-threatening situations. This problem can be found in any breed of dog, but there are known predispositions to some of the clotting disorders of the platelets.

Platelets are also known as thrombocytes and play an important role in the bleeding process. Hemostatic disorders are characterized by repeated bleeding occurrences and a lack of ability to stop bleeding once it has started. When there is a problem with the platelets in the clotting process, it can lead to serious consequences for your pet.

Symptoms will vary from disorder to disorder but depending on the condition, your dog may show symptoms indicative of a serious problem. Do not delay in taking your beloved pet to the veterinarian if you see any signs that he may be suffering from a bleeding affliction.

• Bleeding of the gums
• Purplish red spotting on the skin
• Blood in the urine
• Black stool
• Nosebleed
• Large bruises
• Prolonged bleeding after injury, surgery, or injection

Some pets may not show signs of a clotting disorder until an incident such as a surgical event whereby excessive bleeding is discovered.

Types

Clotting disorders of the platelets are classified in two ways.

• Congenital - some canines are born with conditions that can range from a mild bleeding tendency to heavy, uncontrollable episodes after injury or surgery
• Acquired - a dog with an acquired clotting disorder may have an illness associated with bringing on the condition, like kidney or liver disease

Clotting disorders are also recognized as having a count of too many platelets, or a decreased platelet amount, meaning not enough for proper function.

There can be many reasons for a clotting disorder of the platelets. At times, the condition will be a secondary condition to an underlying ailment. Other cases may be evident after a congenital cause is discovered.

Congenital

Bassett thrombopathia

• Platelets fail to react normally during a bleed
• Bassett Hound and Finnish Spitz breeds are predisposed

Von Willebrand disease

• Deficiency of the Von Willebrand factor
• Most common congenital bleeding disorder in canines
• Breeds prone are Scottish Terrier, Standard Poodle, Standard Manchester Terrier, Doberman Pinscher, German Shepherd, Golden Retriever, Miniature Schnauzer, Pembroke Welsh Corgi, Shetland Sheepdog, Bassett Hound, and Rottweiler

Cyclic hematopoiesis

• 12 day cycles where the platelets decrease
• Gray Collies are predisposed

Congenital thrombocytopenia

• Lack of platelets in the fetus because the mother’s body produces antibodies against proteins in the fetus’ platelets

Thrombasthenia

• Protein disruption leading to platelet dysfunction
• Otterhounds and Great Pyrenees are predisposed

Other breeds known to be susceptible to congenital clotting disorders of the platelets are the American Cocker Spaniel, Boxers, Collies, and German Shepherds

Acquired

Thrombocytopenia due to vaccine

• Results in a platelet loss after a vaccine
• Lasts a short time only

Ehrlichial diseases

• Severe drop in platelet count
• It is a tick-borne illness

Also acquired are thrombocytopenia due to medication (suppression of platelets in bone marrow) and thrombocytopenia due to an abnormality within the immune system (platelets are destroyed by antibodies made by the immune system). Other causes for a platelet disorder can be chronic infection, neoplasia, leptospirosis, bone marrow tumor, hepatitis, parvovirus, and anemia.

The diagnosis of a platelet disorder may be obtained in clinically by symptoms, but it is better to definitively diagnose via testing. To commence the diagnostic process, however, the veterinarian will begin with a physical examination of your canine companion. When a platelet clotting problem is suspected, a careful observation of the mucus membranes, eyes, joints, and skin can provide valuable information as to whether a bleeding issue is possible.

A fecal analysis, urinalysis, complete blood count, and serum biochemical study will be a standard part of the visit as well. These tests may be able to determine if there is an underlying illness or systemic disease that is causing the uncontrollable bleeding.

Specific testing may be in order that will give evidence to platelet function, size, decrease or overabundance. These tests could include:

• Platelet aggregation
• Flow cytometry
• Clot retraction
• Secretion studies
• Smear evaluation
• Abnormal function
• Coagulation function
• Platelet count

There is really no treatment for blood disorders; a cure is not to be expected. However, management is possible except in cases where the platelet issue is life-threatening. An example of this would be cyclic hematopoiesis. Most dogs with this clotting disorder die from infection before the age of three.

With other illnesses involving the platelets, there is often no specific treatment, but in the case of a severe bleeding episode, a transfusion of plasma or whole blood could be needed. In any case, your veterinarian will treat a concurrent or underlying disease if needed.

Canines with clotting disorders of the platelets may be subjected to mild bleeding episodes only, while others will have serious episodes after injury or surgery. Your veterinarian can best advise you on how to manage the symptoms. In addition, if a surgical or dental procedure is ever needed the veterinarian will be prepared to deal with an excessive bleeding episode accordingly.