Case Description: A 5.5-year-old male castrated mixed breed dog was evaluated due to an acute onset of neurologic signs, primarily facial spasms, and a marked polycythemia detected by the primary veterinarian. Clinical Findings: Hyperemic mucous membranes, injected sclera, thoracolumbar pain, intermittent facial spasms, and hypertension. Point of care blood work revealed a severe polycythemia. A Complete Blood Count confirmed this finding and revealed significant numbers of nucleated red blood cells. Thoracic radiographs and an abdominal ultrasound were unremarkable. A bone marrow aspirate displayed erythroid, myeloid, and megakaryocyte hyperplasia. Treatment and Outcome: The marked polycythemia and evidence of continued stimulation of the bone marrow pointed to a diagnosis of absolute polycythemia. No evidence of neoplasia, specifically renal neoplasia, was found on diagnostic imaging, leading to a presumptive diagnosis of polycythemia vera. The patient was repeatedly phlebotomized and was discharged on anti-hypertensives and hydroxyurea. Following initiation of treatment, the patient’s clinical signs resolved completely.
Clinical Relevance: Polycythemia vera is an indolent disease that is likely underdiagnosed in veterinary medicine. While the etiology behind polycythemia vera has been elucidated in human medicine, the answer remains less clear in veterinary patients. Increased knowledge about the disease process and presenting signs may lead to more thorough surveillance of patients in the future.