Thrombocytopenia in Dogs

Thrombocytopenia in Dogs

By: Dr. Leah Cohn

Section: Information In-depth

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:

  • Vasculitis. This inflammatory disease of blood vessels is characterized by tiny defects in the lining that can allow blood to leak from the vessels. Platelets are attracted to these defects and attempt to plug the holes. Consequently, vasculitis often also results in thrombocytopenia. Several different disease processes can cause vasculitis, including some types of infection and abnormal immune system function that results in an attack against the vessel walls.

  • Von Willebrand's disease. The is an inherited defect in a body protein that normally facilitates the attachment of platelets to each other and to damaged vessel walls. Animals with this disorder have prolonged bleeding times and sometimes experience excessive bleeding after minor injury or surgical procedures. It is an inherited trait in several breeds of dogs, notably Doberman pinschers.

  • Insufficient quantities of coagulation proteins. Inherited deficiency of a coagulation protein is known as hemophilia. Certain disease processes such as liver failure can result in acquired deficiency of coagulation proteins.

  • Warfarin. Ingestion of this compound, a common ingredient in rat poisons, can result in a life-threatening bleeding disorder. Some of the currently available rat poisons contain ingredients that have the same effect as warfarin but are much more potent and longer acting. These poisons affect vitamin K metabolism such that coagulation proteins cannot be properly activated.

  • Disseminated intravascular coagulation (DIC). This refers to life-threatening bodywide coagulation that occurs as a complication of several serious diseases including infections and cancer. During development of DIC, tiny clots form throughout the body in small blood vessels. Both platelets and coagulation proteins are consumed in the formation of these small clots. Widespread life-threatening bleeding occurs when the body's platelets and coagulation proteins become depleted.

  • Disease in specific organs or body locations. Diseases can cause bleeding that is localized to those areas. For example, bladder stones can cause blood in the urine, nasal tumors can cause bleeding from the nostrils (often primarily on one side), gum disease can cause bleeding around the teeth, and trauma can cause bruising or bleeding.

  • Skin rashes can be mistaken for the tiny pinpoint hemorrhages called petechiae that are found in animals with severe thrombocytopenia. When finger pressure is placed on the red spots in a rash, the redness typically blanches out whereas with petechiae, the redness stays.

     
    Printable Version
     
    Have a Pet Question?
    Send Your Pet Question to Dr. Jon
    and His Staff of Veterinarians Ask Dr. Jon
    Dr. Jon's Newsletter
    Yes! Send Me the Latest Health Information, Pet Tips, Pet Stories and more...
     
     

    Related Articles

    • 1 Bruising and Bleeding in Dogs

      Bruising and bleeding are disorders of primary hemostasis – or clotting – that result in bleeding into the skin or mucous membranes to a degree out of proportion to the trauma. The impact may be mild...

      Read MoreRead More
    • 2 Anemia in Dogs

      Anemia is defined as a low red blood cell count. Anemia can be caused by a number of different processes, including blood loss, red blood cell destruction, and inadequate red blood cell production.

      Read MoreRead More
    • 3 Immune Mediated Hemolytic Anemia in Dogs (IMHA), Autoimmune Hemolytic Anemia

      IMHA is a disease in which the body’s immune system, which is designed to attack and kill germs, attacks and kills the body’s own red blood cells; it occurs more often in dogs than in cats and in middle...

      Read MoreRead More
    • 4 Von Willebrand’s Disease (VWD)

      Von Willebrand’s disease (vWD) is caused by a deficiency of von Willebrand’s factor (vWF), one of the elements that allow blood to form clots. Von Willebrand’s disease can cause prolonged or excessive...

      Read MoreRead More
    • 5 Bleeding Disorders in Dogs

      Bleeding disorders are diseases in which the blood does not clot normally, causing a tendency to bleed abnormally or excessively after minor bumps or cuts. The effects on your pet are related to how much...

      Read MoreRead More
  • Related Articles
    • 1 Bruising and Bleeding in Dogs

      Bruising and bleeding are disorders of primary hemostasis – or clotting – that result in bleeding into the skin or mucous membranes to a degree out of proportion to the trauma. The impact may be mild...

      Read MoreRead More
    • 2 Anemia in Dogs

      Anemia is defined as a low red blood cell count. Anemia can be caused by a number of different processes, including blood loss, red blood cell destruction, and inadequate red blood cell production.

      Read MoreRead More
    • 3 Bleeding Disorders in Dogs

      Bleeding disorders are diseases in which the blood does not clot normally, causing a tendency to bleed abnormally or excessively after minor bumps or cuts. The effects on your pet are related to how much...

      Read MoreRead More
    • 4 Immune Mediated Hemolytic Anemia in Dogs (IMHA), Autoimmune Hemolytic Anemia

      IMHA is a disease in which the body’s immune system, which is designed to attack and kill germs, attacks and kills the body’s own red blood cells; it occurs more often in dogs than in cats and in middle...

      Read MoreRead More
    • 5 Von Willebrand’s Disease (VWD)

      Von Willebrand’s disease (vWD) is caused by a deficiency of von Willebrand’s factor (vWF), one of the elements that allow blood to form clots. Von Willebrand’s disease can cause prolonged or excessive...

      Read MoreRead More
     

    Over 10,000 Veterinarian Approved Articles

    Related Articles
    • 1 Bruising and Bleeding in Dogs

      Bruising and bleeding are disorders of primary hemostasis – or clotting – that result in bleeding into the skin or mucous membranes to a degree out of proportion to the trauma. The impact may be mild...

      Read MoreRead More
    • 2 Anemia in Dogs

      Anemia is defined as a low red blood cell count. Anemia can be caused by a number of different processes, including blood loss, red blood cell destruction, and inadequate red blood cell production.

      Read MoreRead More
    • 3 Bleeding Disorders in Dogs

      Bleeding disorders are diseases in which the blood does not clot normally, causing a tendency to bleed abnormally or excessively after minor bumps or cuts. The effects on your pet are related to how much...

      Read MoreRead More
    • 4 Immune Mediated Hemolytic Anemia in Dogs (IMHA), Autoimmune Hemolytic Anemia

      IMHA is a disease in which the body’s immune system, which is designed to attack and kill germs, attacks and kills the body’s own red blood cells; it occurs more often in dogs than in cats and in middle...

      Read MoreRead More
    • 5 Von Willebrand’s Disease (VWD)

      Von Willebrand’s disease (vWD) is caused by a deficiency of von Willebrand’s factor (vWF), one of the elements that allow blood to form clots. Von Willebrand’s disease can cause prolonged or excessive...

      Read MoreRead More