Diagnosis and Treatment of Primary Erythrocytosis in a Dog: A Case Report

Multifocal cerebral haemorrhage in two dogs with erythrocytosis

“…A presumptive diagnosis of erythrocytosis is based on a history of polydipsia, polyuria, exercise intolerance and episodes of abnormal behavioural and/or neurological deficits in patients with a markedly elevated PCV 1,2,7–10 . Primary and secondary erythrocytosis are distinguished by the presence or absence of an underlying cause for elevated EPO production 1–3,6,10 . Elevated EPO can be caused by chronic hypoxaemia, such as with cardiac disease causing right‐to‐left shunting or chronic pulmonary disease 1,2,5 .…”

“…Additionally, excessive EPO production from neoplastic renal tissue can cause secondary eythrocytosis 29 . While assessment of EPO levels can support a diagnosis of erythrocytosis, there is a considerable overlap in EPO serum concentration in clinically normal dogs and cats, and those with primary or secondary erythrocytosis 1–3,10,30 . Where no underlying cause is identified, primary erythrocytosis is assumed.…”

“…The first case was diagnosed with primary erythrocytosis, with extensive cerebral haemorrhages. Primary erythrocytosis (or polycythaemia vera) has been reported in dogs previously 7–10 . One previous report documented acute forebrain ischaemic infarction in a dog, 9 without documented haemorrhage.…”

“…Clinical signs reported in dogs with erythrocytosis include erythema, epistaxis, uveitis, polyuria, polydipsia and neurological deficits (including behavioural changes, tetraparesis and seizures); all attributed to hyperviscosity syndrome 1,2,7–10 . To date, there is limited information available on erythrocytosis as a cause of neurological dysfunction in the veterinary literature.…”

“…2 Clinical signs reported in dogs with erythrocytosis include erythema, epistaxis, uveitis, polyuria, polydipsia and neurological deficits (including behavioural changes, tetraparesis and seizures); all attributed to hyperviscosity syndrome. 1,2,[7][8][9][10] To date, there is limited information available on erythrocytosis as a cause of neurological dysfunction in the veterinary literature. A case report documented a dog with cerebral infarction caused by primary erythrocytosis, detected on magnetic resonance imaging (MRI) of the head, and subsequently confirmed histopathologically.…”