Toxoplasmosis Chorioretinitis

Introduction

Toxoplasma gondii causes unilateral necrotising chorioretinitis, or chorioretinal scar.
- In the active stage, lesions appear yellow
- In the inactive stage, lesions appear white
- Reactivation is typically accompanied by systemic conditions like fever, malaise and lymphadenopathy
- In immunocompromised, scars can cause extensive retinal necrosis and possibly panuveitis

Dead Giveaways

Fundus Appearance:

Shows the new active scar next to the old pigmented scars. The disc is fairly blurry and hyperaemic (papillitis)

OCT Appearance:

Large chorioretinal atrophy is present over the region of scarring, leading to increased choroidal transmission.

diagnostic features

Signs:

"Fluffy" lesions with indistinct margins
Focal vitreous infiltrate near lesion
Periphlebitis
Papillitis or optic disc oedema
Vitritis
Anterior uveitis
Exudation can occur, and lead to macula oedema as well, which will greatly affect visual acuity
On resolution, a scar remains, but with chronicity becomes pigmented