Toxoplasmosis Retinochoroiditis - Reactivation of Infection

This 60-year-old patient was originally seen in June 2015 complaining of a scotoma superior to fixation in the right eye. At that time, his visual acuity was 20/16 in both eyes. The differential diagnosis was branch retinal artery occlusion versus primary acquired toxoplasmosis retinitis. On examination his right eye was normal but his left retina had an area of whitening inferior to the fovea (green arrow). Toxoplasma gondii IgM was negative but IGG was markedly high. These results were consistent with reactivated toxoplasmosis retinitis rather than primary acquired toxoplasma retinitis. He was put on Septra DS twice a day for 5 months. At his visit in December, the infection had regressed leaving a scar in his left eye (white arrow) and his vision remained at 20/16. This is an interesting case because not pre-existing scar was seen, but serologically the evidence supported a reactivated infection.