Thrombocytopenia (Low Blood Platelets) in Dogs

Overview of Thrombocytopenia in Dogs

Thrombocytopenia refers to an abnormally low blood-concentration of platelets, which are blood cells that promote blood clotting after injury to the lining of the blood vessels. When the concentration of platelets becomes too low, bruising and bleeding may occur. Dogs with blood platelet concentrations of less than 40,000 per microliter of blood are at risk for spontaneous bleeding.

Abnormally low platelet numbers in blood can be caused by a variety of disease processes. These include failure to produce new platelets in the bone marrow, premature destruction of circulating platelets often by the body’s own immune system, sequestration or storing of platelets in organs, and consumption of platelets at a rate that exceeds production in the bone marrow.

Dogs of either gender, any age and any breed can suffer from thrombocytopenia.

The severity of bleeding associated with thrombocytopenia depends on how low the platelet numbers fall. In general, the lower the platelet count, the more likely bleeding is to occur.

What to Watch For

Symptoms of thrombocytopenia in dogs may include:

Diagnosis of Thrombocytopenia (Low Blood Platelets) in Dogs

Diagnostic tests are needed to recognize thrombocytopenia and exclude other diseases. Tests may include:

Treatment of Thrombocytopenia (Low Blood Platelets) in Dogs

Treatment for thrombocytopenia depends on the underlying cause of the low platelet count.

Home Care and Prevention

Administer as directed all medications prescribed by your veterinarian. Keep your dog calm and confined indoors to prevent bleeding and bruising. Watch for signs of bleeding or bruising and call your veterinarian immediately if such signs occur or worsen.

Prevent tick bites whenever possible because ticks transmit the bacterial agents (rickettsia) that cause ehrlichiosis and Rocky Mountain spotted fever, diseases that cause thrombocytopenia. Use tick preventives and check your dog daily for ticks during warm weather. Other causes of thrombocytopenia are not preventable.

In-depth Information on Canine Thrombocytopenia

Thrombocytopenia does not always lead to excessive bleeding. Normally, there are more than 600,000 platelets per microliter of blood, which is about one millionth of a quart. Platelet numbers in blood must fall to about 10,000 to 40,000 per microliter before spontaneous bleeding becomes likely. Moderate thrombocytopenia may be found in animals with no evidence of bleeding and this finding often serves as a clue to an important underlying disease process.

Thrombocytopathia is a term that refers to abnormal function of platelets. Animals with thrombocytopathia have adequate numbers of platelets in their blood, but the platelets do not function properly. Thrombocytopathia may be inherited or acquired. Acquired defects in platelet function may be due to drugs (such as aspirin), cancer, or organ failure (such as kidney failure, liver failure).

Coagulation refers to the clotting ability of blood, and normal coagulation arises from the combined effects of properly functioning platelets, blood vessel lining cells (endothelium) and protein clotting factors found in the blood and tissues. Deficiency or abnormal function of any of these components can cause spontaneous bleeding. Occasionally, a disease causes defects in more than one of these components simultaneously.

The following disease processes may cause symptoms similar to those seen in dogs with severe thrombocytopenia:

In-depth Information on Diagnosis of Canine Thrombocytopenia

Specific diagnostic tests will be needed for your veterinarian to diagnose thrombocytopenia, determine its underlying cause and determine the effects of thrombocytopenia. Tests may include:

Unfortunately, a highly reliable diagnostic test is not available for one of the most common causes of severe thrombocytopenia in dogs called immune-mediated thrombocytopenia or idiopathic thrombocytopenic purpura (ITP). Immune-mediated diseases result when the body’s immune system fails to recognize its own cells and tissues and begins to attack them as if they were foreign invaders. In immune-mediated thrombocytopenia, the immune system attacks and destroys platelets. Due to lack of a reliable and specific diagnostic test for this disease, immune-mediated thrombocytopenia usually is diagnosed by ruling out other known causes of thrombocytopenia.

Additional diagnostic tests may be recommended on a case-by-case basis to determine the cause of thrombocytopenia and to insure that your dog receives optimal medical care. Examples of additional tests may include the following:

In-depth Information on Treatment of Canine Thrombocytopenia

Specific treatment of dogs with thrombocytopenia depends on the cause. If the animal is not bleeding and the platelet count is not seriously low, the underlying cause of the thrombocytopenia is usually treated without specifically attempting to treat the thrombocytopenia itself. If the specific cause of thrombocytopenia can be treated successfully, platelet numbers will increase quickly. The best approach is to treat the underlying disease responsible. If thrombocytopenia is severe and likely to result in bleeding, the following may be considered:

Follow-up Care for Dogs with Thrombocytopenia

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be crucial. Administer as directed any medications prescribed by your veterinarian and notify your veterinarian if you are experiencing problems treating your dog.

If your dog is at home while his platelet count is very low, keep the animal calm and confined to minimize the chance of bruising and bleeding. Observe your dog closely for signs of bleeding. Look at the whites of the eyes (sclera), gums, and skin for characteristic red spots (petechiae) or bruises (ecchymoses). Call your veterinarian immediately if you observe any petechiae, bruising, or bleeding or if your dog becomes very lethargic or shows any abnormal behavior.

Return to your veterinarian on a regular basis to re-evaluate the platelet count until platelet numbers approach normal. There is no substitute for an accurate blood platelet count.