A 9-year 9-month-old male beagle dog was suspected to have optical deficits. The dog therefore underwent ophthalmologic examinations. During follow-up, at 10 years and 4 months of age, paralysis of the extremities developed. The prognosis was hence considered to be poor. The dog was examined pathologically after euthanasia.
The ophthalmologic examination revealed binocular mydriasis and the disappearance of ophthalmologic reflex reactions, indicating vision loss. Fundus examinations showed yellow coloration around the optic disk. On pathological examination, cupping of the optic disc and peripapillary atrophy were observed. In addition, the bilateral optic nerves exhibited infiltration of inflammatory cells (lymphocytes, plasma cells and macrophages), and atrophic degeneration of fibers. In the brain and the spinal cord as well, infiltrations of inflammatory cells the same as those observed on the optic nerves were extensive and perivascular. In particular, Th5 of the thoracic cord showed remarkable granulomatous inflammation.
These results suggested that this dog had first developed the “ocular type” of granulomatous meningoencephalomyelitis (GME), resulting in vision loss. Subsequently, the inflammation had apparently progressed to the “disseminated type” of GME, resulting in paralysis of the extremities.