Toxoplasmosis: Retinal Infiltrate
The yellow-white area with fuzzy edges is a retinal infiltrate. It consists of inflammatory cells, dead retinal tissue, and, in this case, toxoplasma organisms. Its indistinct margins and overlying vitreous haze distinguish it from the other yellow-white things in the retina (Yellow-White Things in the Retina).
When such an infiltrate heals, it will leave a . If full-thickness retina and choroid have been destroyed, you will be looking straight through to the white sclera. Black pigment usually rings the scar.
Other causes of retinal infiltrates are systemic bacterial sepsis, candidiasis, herpes simplex or zoster, sarcoid, lues, and filariasis.
In immunocompetent hosts, this condition usually represents satellite reactivation of a congenital lesion, evident as an adjacent .
In immunocompromised hosts, toxoplasmosis is usually acquired, and no old scars are seen. The patient probably also has toxoplasmic lesions elsewhere in the brain.
Treatment consists of a regimen made up of various combinations of systemic pyrimethamine (with folinic acid rescue), sulfadiazine, prednisone, and clindamycin.