Acute Neuro-Retinitis Secondary to a Recently Acquired Ocular Toxoplasmosis in a Young Immunocompetent Patient

A 27-year-old male patient with no medical history presented with a painless unilateral vision loss in the right eye, counting fingers at 5 meters, with active vitreous inflammation, stage II papilledema, whitish lesion on the superior-temporal border of the optic disc and a poor macular reflex, without any active or scarring chorioretinal lesion in the periphery. Multimodal imaging showed intra- and subretinal macular edema with early hypo-fluorescence followed by progressive centripetal filling of the peripapillary lesion and finally papillary diffusion. The visual field revealed an inferotemporal defect. Blood work showed hyperleukocytosis with positive toxoplasma serology, the rest of the workup was negative, especially no immunosuppression. The diagnosis of toxoplasmic anterior optic neuropathy was made due to the papillary and peripapillary involvement without a distant active or scarring lesion, with positive toxoplasma IgG and IgM serology. Trimethoprim/sulfamethoxazole antibiotic treatment with systemic corticosteroid therapy was initiated in our patient with an excellent outcome, including restoration of visual acuity to 10/10, complete vitreous clearance, complete resolution of the papillary and macular edema, and the peripapillary lesion without visible scarring, but leaving a persistent defect of the corresponding retinal nerve fibers. This clinical case thus illustrates a toxoplasmic anterior optic neuropathy with direct papillary involvement complicated by macular edema, a rare and atypical clinical entity of ocular toxoplasmosis, especially in a young immunocompetent subject, reflecting the clinical polymorphism of this pathology.