Image of the Month - September 2021

This image series illustrates primary toxoplasmosis chorioretinitis in a young man. Note the focal retinitis lesion on the widefield fundus photo, associated mild vasculitis and hot optic nerve on fluorescein angiography. The toxoplasmosis lesion itself is initially blocking and later forming a peripheral ring of staining on the fluorescein angiography. The causative organism is Toxoplasma gondii, a single cell intracellular protozoan parasite. Toxoplasma chorioretinitis can be due to a primary infection or secondary recurrence. This case is a good example for a primary infection without nearby accompanying old scar as well as confirmatory positive IgM titer. Management for Toxoplasma chorioretinitis consists of week-long antibiotic therapy (multiple regimen exists) as well as steroids. The prognosis is generally favorable with the exception of lesions in the macula or papillomacular bundle.