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Toxoplasmosis

Figure 1. Color retinography of the right eye showing the inferior pigmented chorioretinal scar, myopic retinochoriodosis, and peripapillary atrophy.

Figure 2. Color retinography of the left eye showing the temporo-inferior pigmented chorioretinal scar in the posterior pole, myopic retinochoriodosis, and peripapillary atrophy.

Description

Toxoplasmosis is caused by Toxoplasma gondii, an intracellular protozoan. The definitive host is the cat, and intermediate hosts include humans, among others. Oocysts are excreted in feline feces and then ingested by the intermediate host in undercooked meat, eggs, or contaminated water supplies. It is also transmitted through the placenta in a woman with active toxoplasmosis. In immunocompetent patients, primary infection is usually subclinical. Regarding ocular manifestations, recurrent episodes of inflammation due to rupture of cysts are frequent. It may cause granulomatous anterior uveitis. The presence of an isolated white and fringed inflammatory focus of retinochoriodosis associated with a pigmented scar is typical. De novo foci not associated with an old scar and multiple lesions are rare in immunocompetent patients, but frequent in immunosuppressed patients. It may cause retinal vasculitis and papilledema. Diagnosis is usually based on clinical examination findings.

Comments

Indication

A 32-year-old woman came to the clinic with a history of ocular toxoplasmosis in childhood and high myopia of 7 diopters in the right eye (RE) and 15 diopters in the left eye (LE). On examination, the visual acuity was one in the right eye and 0.15 in the left eye (Snellen decimal scale). Biomicroscopy showed no abnormalities in the anterior pole, and in the posterior pole, myopic chorioretinal atrophy was noted with an area of inferior chorioretinal atrophy in the RE and an area of chorioretinal atrophy in the posterior pole and nasal periphery in the LE, with no signs of activity (Figures 1 and 2). An oblique insertion of the papilla with peripapillary atrophy and retinochoroidosis were also observed, typical findings of high myopia.