Primary Erythrocytosis (Polycythaemia) in a Neutered Male Dog Presenting With Right Hindlimb Lameness
4 affiliations
- 1Veterinary Internal Medicine Service Hospital for Small Animals Royal (Dick) School of Veterinary Studies Easter Bush Campus, University of Edinburgh Edinburgh UK
- 2Veterinary Neurology/Neurosurgery Department Hospital for Small Animals Royal (DIck) School of Veterinary Studies, University of Edinburgh Easter Bush Campus, University of Edinburgh Edinburgh UK
- 3Veterinary Emergency and Critical Care Department Hospital for Small Animals Royal (Dick) School of Veterinary Studies Easter Bush Campus, University of Edinburgh Edinburgh UK
- 4Veterinary Diagnostic Imaging Department Hospital for Small Animals Royal (Dick) School of Veterinary Studies Easter Bush Campus, University of Edinburgh Edinburgh UK
Abstract
A 2‐year‐old male entire Cocker Spaniel was referred for investigation of progressive right hindlimb lameness and polyuria and polydipsia. Investigations conducted by the primary care veterinary surgeon revealed erythrocytosis (haematocrit of 78%, reference interval: 37%–55%) and urine concentration consistent with polyuria and polydipsia (specific gravity 1.014). Upon referral, physical examination revealed a dark red oral mucosa and right hindlimb lameness, characterised by intermittent non‐weight bearing of the limb when standing. Neurological examination only revealed a mild short‐strided gait, and orthopaedic examination was unremarkable. Secondary causes of erythrocytosis were excluded by normal arterial blood gas, low erythropoietin levels and normal thoracic and abdominal imaging, resulting in a diagnosis of primary erythrocytosis (PE). Focal ultrasonography identified a right external iliac venous thrombus, suspected to be the cause of the right hindlimb lameness and presumed to be associated with the PE. Initial management involved repeated phlebotomies, followed by long‐term treatment with hydroxyurea (31 mg/kg twice weekly) and rivaroxaban (2 mg/kg once daily). At the 5‐month recheck, the dog was asymptomatic, with resolution of the iliac thrombus and a normal haematocrit. This case highlights an unusual presentation of PE in a dog, not previously described in the veterinary literature, and re‐examines the discussion on the optimal management of this rare condition, with a focus on the necessity of antithrombotic therapy.
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BibTeX
@article{belch2026primary,
title = {{Primary Erythrocytosis (Polycythaemia) in a Neutered Male Dog Presenting With Right Hindlimb Lameness}},
author = {Robyn Belch and Perrine Henry and Marisa Ferreira and Albert Aguilera Padros and Maria Lazaro Munoz and Ben Lloyd‐Bradley and Ingrid Isaac and Efa Llewellyn and Aran Nagendran},
journal = {Veterinary Medicine and Science},
year = {2026},
month = nov,
doi = {10.1002/vms3.71320},
url = {https://doi.org/10.1002/vms3.71320},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Primary Erythrocytosis (Polycythaemia) in a Neutered Male Dog Presenting With Right Hindlimb Lameness
AU - Robyn Belch
AU - Perrine Henry
AU - Marisa Ferreira
AU - Albert Aguilera Padros
AU - Maria Lazaro Munoz
AU - Ben Lloyd‐Bradley
AU - Ingrid Isaac
AU - Efa Llewellyn
AU - Aran Nagendran
PY - 2026
DA - 2026/11/03
JO - Veterinary Medicine and Science
DO - 10.1002/vms3.71320
UR - https://doi.org/10.1002/vms3.71320
AB - A 2‐year‐old male entire Cocker Spaniel was referred for investigation of progressive right hindlimb lameness and polyuria and polydipsia. Investigations conducted by the primary care veterinary surgeon revealed erythrocytosis (haematocrit of 78%, reference interval: 37%–55%) and urine concentration consistent with polyuria and polydipsia (specific gravity 1.014). Upon referral, physical examination revealed a dark red oral mucosa and right hindlimb lameness, characterised by intermittent non‐weight bearing of the limb when standing. Neurological examination only revealed a mild short‐strided gait, and orthopaedic examination was unremarkable. Secondary causes of erythrocytosis were excluded by normal arterial blood gas, low erythropoietin levels and normal thoracic and abdominal imaging, resulting in a diagnosis of primary erythrocytosis (PE). Focal ultrasonography identified a right external iliac venous thrombus, suspected to be the cause of the right hindlimb lameness and presumed to be associated with the PE. Initial management involved repeated phlebotomies, followed by long‐term treatment with hydroxyurea (31 mg/kg twice weekly) and rivaroxaban (2 mg/kg once daily). At the 5‐month recheck, the dog was asymptomatic, with resolution of the iliac thrombus and a normal haematocrit. This case highlights an unusual presentation of PE in a dog, not previously described in the veterinary literature, and re‐examines the discussion on the optimal management of this rare condition, with a focus on the necessity of antithrombotic therapy.
SN - 2053-1095
ER -