Acute progress of necrotizing meningoencephalitis in a dog; serial clinical observation, magnetic resonance imaging, and histopathological findings

A 13-month-old intact female poodle dog presented with an acute history of circling and seizure episodes. On the basis of the results of neurologic examination combined with magnetic resonance imaging and cerebrospinal fluid analysis (CSF), meningoencephalitis of unknown etiology (MUE) was suspected. Therapy with mycophenolate mofetil plus prednisolone was initiated, following which the clinical signs showed improvement for only one month before gradually worsening again. Acute progression of the clinical disease was observed, and the patient was euthanized 91 days after initial presentation. This case was definitively diagnosed as necrotizing meningoencephalitis (NME) according to the results of post-mortem histopathological examination. This report describes the clinical findings, serial magnetic resonance imaging (MRI) characteristics, and histopathological changes in a case of acute NME.