Make Your Diagnosis Progressive Cerebellar Ataxia in an Adult Dog

History Scout, a previously healthy, 6-year-old, spayed English springer spaniel show dog, was presented with a 2-month history of progressive incoordination and head tilt. Signs progressed despite treatment with amoxicillin/clavulanic acid for presumptive otitis media or interna. Slight resolution of the head tilt was observed after an anti-inflammatory dose of prednisone. Metronidazole had not been administered. Examination showed a right head tilt, wide-based stance, nodding movement of the head and body (ie, titubation), intention tremors, ambulatory cerebellar ataxia (worse on the right), absent right menace response, mild right facial paresis, and a positional ventrolateral strabismus in the right eye. Neuroanatomical localization was to the right cerebellomedullary angle.