Management of bilateral uveitis in a Toxoplasma gondii-seropositive cat with histopathologic evidence of fungal panuveitis

Abstract

A 5-year-old, neutered male Domestic Short-haired cat was referred with a 5-month history of anterior uveitis and cataract in the right eye. Clinical examination confirmed anterior uveitis and immature cataract in the right eye and chorioretinitis in the left eye. Ocular ultrasound showed a retinal detachment in the right eye. Diagnostic testing revealed elevated serum titers for Toxoplasma gondii. Anterior uveitis in the right eye and chorioretinitis in the left eye progressed, resulting in blindness despite a 21-day course of clindamycin and aggressive topical medical management of uveitis. The right eye was enucleated and histopathologic evaluation of the globe revealed panuveitis and multiple organisms morphologically consistent with Histoplasma capsulatum. Systemic treatment with itraconazole was initiated. Vision returned after 3 months of treatment and complete resolution of the retinal hemorrhages with formation of a flat chorioretinal scar was noted after 6 months of therapy. Itraconazole was discontinued 7 months after starting therapy, at which time the funduscopic appearance of the chorioretinal scar had remained static for 1 month. The cat has remained visual without evidence of disease progression for 6 months following discontinuation of itraconazole.

Figure 1

Fundus photograph of the left eye at presentation. A focal, raised, mottled chorioretinal lesion is apparent within the lateral mid‐peripheral tapetal fundus. Also note the multifocal white vitreal opacities closely associated with the chorioretinal lesion (arrows).

Figure 2

Ocular ultrasound image of the right eye at presentation. Complete retinal detachment is present with thickening of the detached retina (arrows).

Figure 3

Fundus photograph of the left eye on day 28. Marked dorsolateral extension of the chorioretinitis and multifocal retinal hemorrhages are present.

Figure 4

Photomicrograph of a section through the dorsal choroid OD revealing intracellular budding yeast‐like organisms measuring approximately 3 µm and consistent with Histoplasma capsulatum (red arrows). Grocott's methenamine silver stain.

Figure 5

Fundus photograph of the left eye 6 months after initiating itraconazole treatment. A flat chorioretinal scar remains in the lateral mid‐peripheral tapetal fundus.