Meningoencephalitis of unknown origin (MUO) is one of the most common inflammatory diseases of the central nervous system (CNS). The study evaluates the possible increase and the potential role of acute phase proteins (APPs) and other inflammatory serum parameters as biomarkers predicting the short-term outcome of dogs with meningoencephalitis of unknown origin (MUO). A retrospective cohort study was designed. The APP profile and other markers of systemic inflammation of forty-eight client-owned dogs with a new diagnosis of MUO were compared between 7-day survival and non-survival dogs diagnosed with MUO. Thirty-nine (81%) dogs were alive at the end of the 7-day follow-up period, while 9 (19%) dogs died or were euthanized because of MUO. None of the 11 markers of inflammation studied were different between the survived and non-survived dogs; for this reason, none of them could be used as a predictor of the short-term outcome based on the results of the present study. This confirms that even though MUO is often associated with a severe inflammatory status of the central nervous system (CNS), this condition is probably isolated exclusively to the CNS.

A four-year-old Scottish Shepherd dog was referred for acute onset of disorientation, blindness and chronic diarrhoea. The neurological examination was consistent with a multifocal neurolocalisation involving the prosencephalon and the brainstem. The ophthalmological exam showed bilateral chorioretinitis with retinal detachment. The brain MRI showed periventricular and left caudate nucleus lesions, increased thickness of the left III, IV, VI and opthalmic branch of V cranial nerves and bilateral multifocal lesions in the temporal and masseter muscles. Cerebrospinal fluid examination showed mild mixed pleocytosis. Faecal and urine cultures were positive for Prototheca zopfii genotype 2. Despite starting itraconazole therapy, the dog’s conditions deteriorated and the owner elected euthanasia. Protothecosis should be suspected in young dogs with multifocal neurological signs, blindness and chronic diarrhoea.MRI study of the central nervous system (CNS), together with blood exam, cytology and cultures, is a useful tool to evaluate the CNS in disseminated form of Prototheca infection.