Secondary thrombocytopaenia due to hyperfibrinolysis in a dog (Canis lupus familiaris) with pericardial effusion

Abstract An 8‐year‐old, male, neutered pug was referred for investigation of a 1‐week history of ascites. On presentation, petechiae and ecchymoses were identified. Haematology including blood smear evaluation revealed a mild thrombocytopaenia with platelet clumping, not low enough to cause clinical bleeding. Prothrombin and activated partial thromboplastin time were within normal limits. Fibrinogen was below the lower detection limit of the analyser and D‐dimers were mildly elevated. A buccal mucosal bleeding time was within normal limits excluding thrombocytopathia. A point‐of‐care direct immunochromatographic serological assay for Angiostrongylus vasorum was negative. Diagnostic imaging showed pericardial effusion with cardiac tamponade and no evident mass. Hyperfibrinolysis was suspected. Treatment with tranexamic acid and pentoxifylline was started during patient hospitalisation and the dog received a transfusion of cryoprecipitate. Once stable, a pericardiocentesis was performed. Cytology of the pericardial fluid was consistent with a haemorrhagic effusion. Within 48 hours of pericardiocentesis, the dog's clinical signs resolved. At reassessment 6 weeks later, there was no evidence of recurrent pericardial effusion suggestive of an idiopathic aetiology; furthermore, the bleeding diathesis remained resolved.