Sudden behavior change in a cat.

A 5-year-old, spayed female, domestic short-haired cat had a 10-day history of sudden behavioral changes followed by seizures. Blood parameters were in the reference ranges, and radiographs failed to detect a mass lesion in the brain. Euthanasia was followed by rabies testing, which was negative. Gross lesions were absent. Histologic changes were present only in the brain and consisted of foci of hippocampal pyramidal cell loss, mild gliosis, pallor of the associated neuropil, and neovascularization.