Management of an aortic thrombus secondary to polycythaemia vera in a dog

A 6‐year‐old, male, neutered American Staffordshire terrier presented with lethargy, anorexia, diarrhoea, hyperaemic conjunctiva and dilated scleral vessels. Bloodwork performed revealed a severe erythrocytosis (haemocrit 71%). The patient underwent a comprehensive diagnostic workup, which ruled out secondary erythrocytosis causes, and treatment was initiated with serial phlebotomies. Two weeks later, the dog presented with acute hindlimb paraparesis, cold extremities and absent femoral pulses. Computed tomography performed confirmed a large aortic thrombus, renal and splenic infarcts, and gastric wall ischaemia. Antithrombotic therapy was started with enoxaparin and clopidogrel, and hydroxyurea was added for presumptive polycythaemia vera. At the time of discharge, the dog was ambulatory with warm hindlimbs and palpable femoral pulses. During initial follow‐ups, the patient was doing well, and serial ultrasonography showed dissolution of the thrombus. Despite an initial favourable response to therapy, the dog was humanely euthanased 3 weeks later for progressive, severe lumbosacral pain refractory to medical management.