Treponemal Endovasculitis leading to branch artery occlusion: a rare manifestation of ocular syphilis.

Ocular syphilis, a re-emerging cause of uveitis, commonly features retinal vasculitis, but branch retinal artery occlusion (BRAO) is a rare, irreversible damaging complication. We present a 47-year-old woman with bilateral syphilitic panuveitis, retinal vasculitis and an inferior BRAO, emphasising the diagnostic value of multimodal imaging. She presented with progressive bilateral blurred vision, exhibiting bilateral nongranulomatous anterior uveitis, vitritis, peripheral vascular sheathing, and multiple chorioretinal lesions. Optical coherence tomography revealed inner retinal thinning consistent with inferior BRAO, and fluorescein angiography showed diffuse vascular leakage consistent with syphilitic retinal vasculitis. Serologic testing confirmed active syphilis. Intravenous penicillin G and topical anti-inflammatory therapy resolved inflammation and with full visual recovery in the right eye. The left eye stabilized with mild persistent visual impairment due to ischemic retinal atrophy. Multimodal imaging for accurate diagnosis is indispensable in cases of unexplained uveitis or retinal vasculitis and timely penicillin treatment-indicated only after syphilis is confirmed through appropriate diagnostic testing-is critical to prevent vision loss.