Case report: A 74-year-old white male presented with one day of a brown hue, light flashes, eye pain, color vision change, and visual hallucinations in the left eye. He denied temporal headache and jaw claudication. Visual acuity was 20/20 in both eyes with no afferent pupillary defect, but the left optic nerve showed chalky, pale edema from 07:00- 13:00 clock hour confirmed by optical coherence tomography. Non-arteritic anterior ischemic optic neuropathy was the leading differential, but because of the risk of impending vision loss he was sent for same-day laboratory testing. Erythrocyte sedimentation rate (73, [ref 0-15mm/hr]) and C-reactive protein (122, [ref <5mg/L]) were markedly elevated. He was admitted, received three days of intravenous corticosteroids, and a temporal artery biopsy performed four days after presentation was positive for GCA. He was transitioned to oral prednisone 60 mg daily. At two-week follow-up, the optic nerve edema had resolved, inflammatory markers had normalized, visual acuity remained 20/20, and a residual inferior arcuate defect persisted in the left eye.

Conclusion: GCA can be presented without the classic symptoms. Any edematous optic nerve in a patient over 50 years of age warrants investigation for GCA, and elevated inflammatory markers should prompt initiation of intravenous corticosteroids while awaiting temporal artery biopsy