Polyneuropathy and primary erythrocytosis in a cat

Abstract

AbstractA 22‐month‐old, male, neutered, domestic longhair cat presented with a 2‐month history of progressive paraparesis and severe muscle atrophy; neuromuscular dysfunction was suspected on neurological exam. A manual packed cell volume was 73%, and serial measurements following fluid therapy remained high. Investigations for secondary causes of erythrocytosis were unremarkable, so a diagnosis of primary erythrocytosis was made. Electromyography showed spontaneous activity within all tested muscles of the pelvic limbs. Motor nerve conduction velocity for the sciatic‐tibial nerve was prolonged, and the compound muscle action potential measured at the hip was reduced. Phlebotomy achieved a reduction of the packed cell volume to 52%, and oral hydroxyurea was started. An improvement in the degree of paraparesis was seen 3 weeks after discharge, and this continued until the cat was normal at 4 months. Fluctuations in the packed cell volume necessitated adjustments in hydroxyurea dosage, but no relapse of paraparesis occurred during the 18‐month follow‐up period.