Acquired and inherited platelet dysfunction in small animals

Acquired and inherited platelet dysfunction, or thrombocytopathy, is encountered in small animal practice but is difficult to diagnose, especially in the clinical setting. Platelet dysfunction can be secondary to renal, hepatic, rickettsial, viral, neoplastic, or immune-mediated disease. The severity of the resulting thrombocytopathy is variable. Many patients do not present with clinical signs of hemorrhage until further deterioration of hemostasis develops. Many drugs cause platelet dysfunction and may complicate these and other disease processes. Acquired thrombocytopathy may potentially resolve with the resolution of the primary disease inducing platelet dysfunction or by withdrawing the offending drug. Von Willebrand's disease is the most common inherited thrombocytopathy and the most common inherited hemostatic defect found in mixed-breed and purebred dogs. Other inherited thrombocytopathies are rarely described and, when present are often associated with specific canine breeds. Effective therapy in inherited thrombocytopathies is difficult. Transfusion of sufficient units of platelet-rich plasma is logistically impractical. Transfusion of whole blood or plasma products theoretically may enhance existing platelet function, especially in von Willebrand factor-deficient patients. The use of drugs known to compromise platelet function should be avoided.