Antibiotics versus control for toxoplasma retinochoroiditis

BACKGROUND: Acute toxoplasma retinochoroiditis causes transient symptoms of ocular discomfort and may lead to permanent visual loss. Antibiotic treatment primarily aims to reduce the risk of permanent visual loss, recurrent retinochoroiditis and the severity and duration of acute symptoms. There is uncertainty about the effectiveness of antibiotic treatment. OBJECTIVES: To compare the effects of antibiotics versus placebo or no treatment for toxoplasma retinochoroiditis. SEARCH STRATEGY: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 1), MEDLINE (January 1950 to February 2011), EMBASE (January 1980 to February 2011), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to February 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (February 2011) and ClinicalTrials.gov (www.clinicaltrials.gov) (February 2011). We also searched the archived National Research Register (NRR) and the UK Clinical Research Network Portfolio Database (UKCRN) on 23 January 2008. Dissertation Abstracts was last searched in June 2001, PASCAL was last searched in March 2000 and proceedings of the Association for Research in Vision and Ophthalmology was searched from 1980 to 2001, we also searched international symposia on uveitis. We searched the reference lists of identified articles and contacted pharmaceutical companies for unpublished trials. There were no language or date restrictions in the search for trials. The electronic databases were last searched on 7 February 2011. SELECTION CRITERIA: We included randomised controlled trials that compared any systemic antibiotic treatment against placebo or no treatment. Trials that included immunocompromised patients were excluded. DATA COLLECTION AND ANALYSIS: The primary outcomes for this review were visual acuity at least three months after treatment and risk of recurrent retinochoroiditis. Secondary outcomes were improvement in symptoms and signs of intraocular inflammation, size of lesion and adverse events. Effect measures were pooled using a random-effects model. MAIN RESULTS: Three trials which randomised a total of 173 participants met the inclusion criteria. All trials were methodologically poor. None reported the effect of treatment on visual acuity. Two studies reported results for recurrent retinochoroiditis: one (124 participants) found a significant reduction in participants in Brazil with chronic recurrent disease who were treated for 14 months (risk ratio (RR) 0.29, 95% confidence interval (CI) 0.10 to 0.81); the other (20 participants) found no evidence of an effect in participants with acute toxoplasma retinochoroiditis (RR 1.00, 95% CI 0.07 to 13.87). Two studies reported an improvement in intraocular inflammation in treated compared with untreated participants and one study reported no difference. Two studies found an increased risk of adverse events in treated participants. AUTHORS' CONCLUSIONS: There is a lack of evidence to support routine antibiotic treatment for acute toxoplasma retinochoroiditis. There is weak evidence to suggest that long-term treatment may reduce recurrence of retinochoroiditis in patients with chronic recurrent toxoplasma retinochoroiditis due to more virulent South American strains of Toxoplasma gondii. Placebo controlled trials of patients with acute and chronic toxoplasma retinochoroiditis affecting any part of the retina are required to determine the effectiveness of antibiotic treatment.