The correct answer is B. Hyperfibrinolysis (ie, accelerated clot breakdown) can cause delayed postoperative bleeding (ie, hemorrhage beginning 36-48 hours postoperatively) in greyhounds.1 Bleeding is characterized by cutaneous bruising that extends from the surgical incision toward the periphery. In a study, 26% of greyhounds experienced delayed postoperative hemorrhage following neutering or ovariohysterectomy.1 No mucosal bleeding or bleeding away from the surgical site occurred.1 In another study, 28% of greyhounds experienced delayed hemorrhage following limb amputation for appendicular osteosarcoma.2 Dogs that experienced delayed bleeding had normal primary and/or secondary hemostasis, and none of the study dogs experienced intraoperative or immediate postoperative bleeding.1 Hemorrhage appears to be self-limiting, although RBC and plasma transfusions may be required in some dogs to treat marked hemorrhage.
Hemophilia A is an X-linked, recessive, inherited coagulation disorder caused by a deficiency of factor 8. Because of hemophilia A’s X-linked inheritance, male dogs are more commonly affected than female dogs. In a study, most affected dogs were crossbreeds, German shepherd dogs, or Labrador retrievers.3 The most common initial signs of hemophilia A include spontaneous bruising or hematoma formation, excessive bleeding after minor trauma or during surgical procedures, gingival bleeding during teething and loss of deciduous teeth, and spontaneous bleeding into a body cavity.3
Von Willebrand disease can occur due to a deficiency or abnormality in the von Willebrand factor, which is stored in platelets and endothelial cells and is essential for platelet adhesion and aggregation at the site of endothelial injury. Many dog breeds are affected by this inherited disorder. The severity of bleeding is variable. Severely affected dogs may have spontaneous mucosal bleeding, whereas less severely affected dogs may only display abnormal bleeding during trauma or surgery.4
Clinically inapparent, idiopathic thrombocytopenia with macrothrombocytosis is an autosomal recessive trait that affects 50% of Cavalier King Charles spaniels.5 Dogs are not clinically affected by this condition, and those with this condition do not have an increased risk for hemorrhage.5,6