Polycythemia vera in a cat with cardiac hypertrophy.

Polycythemia vera, a rare and poorly documented disease in cats, was diagnosed in a 4-year-old domestic shorthair cat admitted because of seizures. The diagnosis was made on the basis of high PCV, normal serum erythropoietin concentration (as determined by bioassay, using rabbit bone marrow cells), and elimination of secondary polycythemia as a diagnosis. Cardiac hypertrophy, which might have been secondary to blood hyperviscosity, also was diagnosed. The cat has been treated by periodic phlebotomy and has been without clinical signs of disease for more than 20 months.