Secondary polycythaemia, hyperviscosity syndrome and unilateral adrenocortical adenoma in a dog

A 14-year-old Collie cross dog was presented because of trembling, incoordi nation, polydipsia and polyuria. Marked congestion of the mucous membranes was the most notable clinical finding. Haematological examination revealed absolute polycythaemia and subsequent demonstration of an inappropriately h igh erythropoietin concentration confirmed secondary polycythaemia with no evidence of hypoxia. The dog was treated by repeated phlebotomy for six mon ths. The polyuria and polydipsia continued, but was not investigated furthe r. The dog was euthanased six months after initial examination. Necropsy co nfirmed mild interstitial nephritis and an enlarged right and an atrophic l eft adrenal gland. Histopathology confirmed the mass as a functional adreno cortical adenoma.