Recurrent episodes of severe bleeding caused by congenital factor XIII deficiency in a dog

Case Description-A 5-year-old castrated male Toy Poodle cross was evaluated because of lethargy, inappetence, and suspected abdominal hemorrhage. The dog had been evaluated on 4 other occasions for episodes of excessive bleeding associated with trauma or surgical procedures. Clinical Findings-At previous evaluations, results of repeated measurements of prothrombin time, partial thromboplastin time, and buccal mucosal bleeding time were unremarkable; activated clotting time, plasma von Willebrand factor concentration, results of platelet function testing, and plasma factor VII, VIII, IX, X, XI, and XII concentrations were considered normal. At this evaluation, clinicopathologic analyses revealed mild regenerative anemia that progressed over a 4-day period to moderate regenerative anemia and acute inflammation with panhypoproteinemia. Abdominal ultrasonography revealed a large mass (suspected to be a hematoma) near the urinary bladder. Rotational thromboelastometry revealed that clotting times were within reference limits, with abnormal clot formation times and clot firmness. The result of a factor XIII (FXIII) clot solubility assay confirmed FXIII deficiency. Treatment and Outcome-The dog's bleeding diathesis resolved with inpatient care and IV fluid therapy, although plasma transfusions had been required at previous evaluations. Seven months after discharge from the hospital, the dog continued to do well clinically, although it had several additional episodes of excessive bleeding. Clinical Relevance-To the authors' knowledge, this is the first reported case of congenital FXIII deficiency in a dog. In addition to more common inherited coagulopathies, FXIII deficiency should be a differential diagnosis for dogs with episodes of excessive bleeding and apparently normal results of standard coagulation tests.