Ocular Syphilis With Unilateral Optic Papillitis and Outer Retinopathy Complicated by Diabetic Retinopathy.

Syphilis has been increasing in adult infections in recent years, and ocular syphilis includes not only uveitis but also a variety of optic nerve and retinal lesions. We report a case of syphilis that caused unilateral optic papillitis and outer retinopathy complicated by diabetic retinopathy and improved with antibiotic treatment. The patient was a 61-year-old woman. During follow-up after vitreous surgery for proliferative diabetic retinopathy, her left visual acuity had decreased, fundus examination revealed redness and swelling of the left optic disc, and a visual field test revealed a central scotoma. Fluorescein angiography (FA) revealed leakage from the optic disc, and magnetic resonance imaging (MRI) revealed high signal intensity and contrast enhancement in the left optic nerve. No signs of uveitis, and the patient was diagnosed with optic neuritis and one course of steroid pulse therapy was performed. Due to improvement of the left optic disc swelling and MRI contrast enhancement, the oral steroids were gradually tapered and discontinued after about one month due to improvement in left optic disc swelling and MRI contrast enhancement. Meanwhile, blood tests during steroid administration revealed quantitative positive syphilis lipid antibodies and treponemal antibodies, and optical coherence tomography (OCT) revealed disruption in the left ellipsoid zone. Early acquired syphilis was diagnosed, and oral penicillin antibiotics were started. Five weeks after starting antibiotics, the outer retinal disruption showed signs of improvement. Ocular syphilis presents with characteristic retinal disorders, but in cases where the onset is optic disc edema, early diagnosis is difficult, and careful differentiation is required.