Canine meningitis and meningoencephalitis in eastern Australia

Meningoencephalitis is an important cause of neurological signs in dogs and may arise from infectious or noninfectious causes. In this retrospective study, dogs with steroid-responsive meningitis arteritis (SRMA), meningoencephalomyelitis of unknown origin (MUO), and eosinophilic meningoencephalomyelitis (EM), living on the east coast of Australia, were evaluated. Data accessed included signalment, clinical signs, magnetic resonance imaging (MRI) and computed tomography (CT) results. C-reactive protein concentration, complete blood count, cerebrospinal fluid analysis, serological tests, medications, duration of treatment, time to relapse and patient outcomes. Of 89 dogs in total, 45 were classified as SRMA, 24 as MUO and 20 as EM. Cervical pain occurred in all dogs with EM and SRMA, and in 50% of dogs with MUO. Dogs with SRMA were less likely to develop paresis than those with EM and less likely to be ataxic than dogs with MUO. Serum CRP concentrations were significantly higher in SRMA compared with MUO and EM (P < 0.01). Twelve dogs, all with eosinophilic pleocytosis, were diagnosed with CNS infections: angiostrongyliasis (n = 11) and cryptococcus (n = 1). A wide variety of treatment protocols were used, underpinned by immunosuppressive medications, with the duration of treatment not significantly different between groups. The most favourable outcomes for dogs with meningoencephalitides in this study were those with EM, which not only had the shortest treatment durations but also had the longest survival times.