Classification Criteria for Toxoplasmic Retinitis.

PURPOSE: To determine classification criteria for toxoplasmic retinitis. DESIGN: Machine learning of cases with toxoplasmic retinitis and 4 other infectious posterior uveitides / panuveitides. METHODS: Cases of infectious posterior uveitides / panuveitides were collected in an informatics-designed preliminary database, and a final database was constructed of cases achieving supermajority agreement on diagnosis, using formal consensus techniques. Cases were split into a training set and a validation set. Machine learning using multinomial logistic regression was used on the training set to determine a parsimonious set of criteria that minimized the misclassification rate among the infectious posterior uveitides / panuveitides. The resulting criteria were evaluated on the validation set. RESULTS: Eight hundred three cases of infectious posterior uveitides / panuveitides, including 174 cases of toxoplasmic retinitis, were evaluated by machine learning. Key criteria for toxoplasmic retinitis included focal or paucifocal necrotizing retinitis and either positive polymerase chain reaction assay for Toxoplasma gondii from an intraocular specimen or the characteristic clinical picture of a round or oval retinitis lesion proximal to a hyperpigmented and/or atrophic chorioretinal scar. Overall accuracy for infectious posterior uveitides / panuveitides was 92.1% in the training set and 93.3% (95% confidence interval 88.2, 96.3) in the validation set. The misclassification rates for toxoplasmic retinitis were 8.2% in the training set and 10% in the validation set. CONCLUSIONS: The criteria for toxoplasmic retinitis had a low misclassification rate and seemed to perform sufficiently well for use in clinical and translational research.

[Ocular toxoplasmosis: our experience]. / La toxoplasmosi oculare: contributo di una casistica personale.

Ocular toxoplasmosis can be a progressive and recurring disease that can threaten visual function. Retinochoroiditis develops gradually weeks to years after subclinical congenital toxoplasmosis; this is the preponderant form, which is frequently bilateral; with healing, white or dark-pigmented scars may result. Toxoplasmosis acquired in older children and adults rarely progresses to retinochoroiditis; it is generally unilateral. We report the results of a clinical study concerning 16 patients with ocular toxoplasmosis observed for the first time in the period from 1992 to 2004 and followed up until today. The patients came to the Department of Infectious Diseases of the Second University of Naples. We studied 16 patients, 10 of whom were females; 11 cases presented ocular signs of congenital toxoplasmosis, while in 5 cases ocular impairment was related to an acquired toxoplasmosis. Only one case of congenital toxoplasma chorioretinitis was symptomatic at birth: it was complicated by microphthalmia and strabismus, calcifications in the brain and epilepsy; 10 congenital cases were asymptomatic at birth and were recognized after several years because of a reactivation of infection. In 5 patients congenital chorioretinitis was bilateral, with presence of scars in the contralateral eye. The 5 cases of acquired toxoplasma retinitis were ascertained by anamnestic, serologic and ophthalmologic examinations; in 4 of them the lesion was typical and unilateral; the 5th case was a 6-year-old boy with acquired toxoplasma bilateral neuroretinitis. 13/16 cases of ocular toxoplasmosis were treated with the combination of pyrimethamine, sulfadiazine; they were followed up and re-treated if necessary. The therapy was curative in each case. Our experience confirms that late-onset retinal lesions and relapse can occur many years after birth but that the overall ocular prognosis is satisfactory when congenital damage is recognized early and treated appropriately. Prevention of congenital and acquired toxoplasmosis is very important in controlling ocular toxoplasmosis.

Presumed toxoplasmosic anterior optic neuropathy.

PURPOSE: To describe the clinical findings and course of toxoplasmic anterior optic neuropathy and to differentiate primary and secondary involvement. METHODS: Retrospective observational case series from a tertiary referral institution. Clinical and photographic charts of 13 patients with toxoplasmosis with direct optic nerve head involvement were reviewed and data were collected throughout the length of follow-up. RESULTS: Toxoplasmic anterior optic neuropathy was divided into two types. Type I was defined as secondary infectious involvement of the optic nerve head from an adjacent focus of chorioretinitis that resolved with chorioretinal scarring. Type II was defined as primary involvement of the optic nerve head that resolved without chorioretinal scarring. Visual acuity improved after treatment in both Type I and Type II patients; however, the visual prognosis was worse in Type I patients due to macular involvement. Eighty-three percent of Type II patients had a final visual acuity equal to or better than 20/25 compared to 50% of Type I patients. Visual field defects were present in all patients, most frequently arcuate or altitudinal (62%). Delay in diagnosis was common (54%), especially in Type II patients (71%). Vitreous inflammation was absent on the initial examination in 31% of the patients. CONCLUSION: Toxoplasmic anterior optic neuropathy is an uncommon manifestation of ocular toxoplasmosis. Delays in diagnosis are common because of the frequent lack of typical chorioretinitis or vitreous inflammation. Adjacent macular involvement strongly influences visual outcome.

Outer retinal layer toxoplasmosis.

It is widely held that ocular toxoplasmosis (1) involves inner retinal layers and (2) shows marked vitreous cellular reaction. This article reports on punctate outer retinal layer toxoplasmosis, a subset of ocular toxoplasmosis characterized by grey-white lesions of deep retina and retinal pigment epithelium, and associated with little or no overlying vitreous reaction. Acute lesions may resolve and become fine punctate white dots. Recognition of this uncommon presentation of toxoplasmosis is important, since this may allow for potentially efficacious therapy.