A 79-year-old female presented with a 2-day history of new onset headache and bilateral vision loss. Outpatient ophthalmologic evaluation reported bilateral retinal pallor, retinal hemorrhages, and cherry red spots. She was admitted to the hospital with concerns for bilateral central retinal artery occlusions.

She was afebrile with visual acuity of light perception only bilaterally. CRP and ESR were elevated. High dose IV steroids were initiated for concerns of giant cell arteritis. MRI brain showed restricted diffusion in bilateral dorsolateral thalami and occipital lobes with mild enhancement. MRI orbits were unremarkable. Five days after admission she became febrile and lethargic. Electroencephalogram showed two nonconvulsive seizures which responded to antiseizure medications. Valacyclovir was started due to concern for encephalitis. Repeat MRI brain demonstrated interval development of large areas of T2/FLAIR hyperintensities involving bilateral occipital lobes, thalami, and right temporal lobe. Lumbar puncture showed mild pleocytosis with elevated protein. CSF PCR was positive for HSV-1. Her mental status failed to improve, and she was transitioned to comfort measures and shortly thereafter passed away. Based on clinical course, her initial vision loss was most likely due to bilateral ARN.