Long-term follow-up of 35 dogs with meningoencephalitis of unknown origin treated with cytosine arabinoside and glucocorticosteroids

BackgroundMeningoencephalitis of unknown origin (MUO) is an idiopathic immune-mediated central nervous system disease. Glucocorticosteroids are the main treatment, often combined with cytosine arabinoside (CA).MethodsThis retrospective, descriptive study evaluated the outcome of a 69-week protocol using glucocorticosteroids and CA (two initial constant rate infusions followed by recurrent subcutaneous injections) in dogs diagnosed with MUO. Outcomes (e.g., treatment success, relapse or death) at 25, 69 and 93 weeks were descriptively analysed and compared to similar protocols reported in the literature. Relapse timing was documented at different treatment stages and glucocorticosteroid dosages.ResultsThirty-five dogs met the inclusion criteria, of which six (17.1%) died within the first 7 days after diagnosis. Overall, 62.9% completed the 93-week follow-up, with 42.9% showing no relapse. Relapse occurred in 40% of dogs, with 20% of these relapsed dogs dying. The majority of dogs relapsed during the treatment protocol.LimitationsLimitations include the study's retrospective and descriptive nature, small sample size and lack of histopathological confirmation.ConclusionThe treatment protocol used in this study does not demonstrate superiority over protocols used in earlier studies. This study emphasises the need for long-term follow-up to detect relapses after treatment discontinuation.