Antibiotics compared with no treatment or placebo for the treatment of toxoplasma retinochoroiditis

Toxoplasma retinochoroiditis occurs when a parasite called toxoplasma gondii gets into the retina (the light sensitive layer inside the eye) and the choroid (layer of the eyeball near the retina). This causes inflammation that can scar the retina and reduce vision. Symptoms include a sudden feeling of discomfort in the eye and loss of vision which usually resolve spontaneously within six to eight weeks. The infection can keep returning, increasing the chances of damage. Antibiotics are sometimes used to try and reduce the inflammation and scarring, or to prevent the infection from re-emerging, but it is not known how well they work. The review found three studies with a total of 173 participants of any age which compared antibiotics with no treatment or a placebo. Two studies examined the effect of antibiotics on reducing the recurrence of episodes of the disease. One study found that in Brazilian adults infected with the more aggressive South American strains of the parasite who have frequently recurring eye symptoms, long-term antibiotics over 14 months reduced the number of recurrent episodes of retinochoroiditis. The second study did not find that short-term treatment with antibiotics made any difference. Side effects of giving antibiotics such as decreased white blood cells, loss of appetite, rashes and other allergic reactions, were investigated in two studies involving the antibiotic pyrimethamine: only weak evidence was found that antibiotics increase the risk of side effects. In all studies, there were problems with the design, conduct and analyses, which could have biased the results. There was a lack of evidence about whether antibiotics (short- or long-term) prevent vision loss. More trials are needed, including trials of newer antibiotics.