Canine meningoencephalitis and meningitis: retrospective analysis of a veterinary hospital population

Abstract

Characterization of the etiology of meningoencephalitis and meningitis in dogs through an analysis of a veterinary hospital population. Retrospective study (2011-2016) with evaluation of clinical and diagnostic data of dogs with cerebrospinal fluid (CSF) pleocytosis (> 5/µl). Only dogs with cytological evaluation of CSF or pathological examination of CNS were included. Results of CSF cytology and examination for infectious diseases were reviewed. A total of 62 dogs met the inclusion criteria. 14.5 % (n = 9) were classified as reactive CSF pleocytosis due to other structural CNS disease, such as neoplasia or infarct. Meningoencephalitis or meningitis of unknown origin was diagnosed in 56.5 % (n = 35). In 29.0 % (n = 18), investigations for infectious diseases or presence of bacteria in CSF cytology (n = 5) indicated an infectious etiology. This infectious etiology appeared reliable in 6 dogs (9.7 %) based on the examination findings, in 9 dogs (14.5 %), there was only a suspicion of infectious meningoencephalitis or meningitis and in 3 dogs (4.8 %), the findings were of uncertain significance. The most common cause of CSF pleocytosis was meningoencephalitis or meningitis of unknown origin. Nevertheless, there was evidence of a possible infectious etiology in 29 % of the dogs. For a reliable diagnosis, it is important to assess the CSF cytology and to conduct investigations for infectious diseases. Meningoencephalitis or meningitis of unknown origin requires immunosuppressive therapy. Therefore, CSF cytology and investigations for infectious diseases are important for an exclusion of infectious meningoencephalitis or meningitis.