Risk of reactivation of toxoplasmic retinitis following intraocular procedures without the use of prophylactic therapy

Association Between Ocular Trauma and Activation of Ocular Toxoplasmosis

PURPOSE

To evaluate the association between ocular trauma and activation of ocular toxoplasmosis.

METHODS

Retrospective review of 686 patients with ocular toxoplasmosis and its association with trauma to the eye or the head within 1 week of activation.

RESULTS

Ten patients with a history of trauma and activation of ocular toxoplasmosis were detected (10/686; 1.45%). Nine patients showed a primary focus of retinitis without a previous scar and one patient had a recurrent form of ocular toxoplasmosis. From these 10 patients, Toxoplasma IgG was positive in eight of them. The median age of the patients was 35.8 years-old (range 17 to 65).

CONCLUSIONS

These cases suggest that trauma can be associated with activation of retinal bradyzoite cysts in ocular toxoplasmosis.

Recurrence of Ocular Toxoplasmosis after Vitrectomy: Case Report and Review

PURPOSE

The purpose of this study is to report one case of ocular toxoplasmosis (OT) recurrence after vitrectomy and review the scientific basis about it.

CASE REPORT

A 58-year-old male patient with previous OT, properly treated, underwent vitrectomy due to macular hole. During follow-up, patient evolved with recurrence of the OT. After 1 year, patient presents visual acuity of 20/200 and extensive macular scar.

CONCLUSION

There is no consensus on using perioperative antiparasitic therapy aiming recurrence prophylaxis. Studies with better statistical design are necessary to evaluate the recurrence risk after ocular surgeries and the possible recommendation of prophylaxis, especially in countries where the strains are more virulent and the recurrence more common.

Risk factors for recurrences and visual impairment in patients with ocular toxoplasmosis: A systematic review and meta-analysis

BACKGROUND

Ocular toxoplasmosis (OT) is caused by the parasite Toxoplasma gondii. OT is the leading cause of posterior uveitis globally; it is a recurrent disease that may result in visual impairment and blindness. This systematic review and meta-analysis aim to summarize and evaluate the risk factors for recurrences, visual impairment, and blindness described in the literature worldwide.

METHODS AND FINDINGS

We performed a systematic literature search in PubMed, Embase, VHL, Cochrane Library, Scopus, and DANS EASY Archive. All studies reporting patients with clinically and serologically confirmed OT presenting any clinical or paraclinical factor influencing recurrences, visual impairment, and blindness were included. Studies presenting secondary data, case reports, and case series were excluded. An initial selection was made by title and abstract, and then the studies were reviewed by full text where the eligible studies were selected. Then, the risk of bias was assessed through validated tools. Data were extracted using a validated extraction format. Qualitative synthesis and quantitative analysis were done. This study was registered on PROSPERO (CRD42022327836).

RESULTS

Seventy two studies met the inclusion criteria. Fifty-three were summarized in the qualitative synthesis in three sections: clinical and environmental factors, parasite and host factors, and treatment-related factors. Of the 72 articles, 39 were included in the meta-analysis, of which 14 were conducted in South America, 13 in Europe, four in Asia, three multinational, two in North America and Central America, respectively, and only one in Africa. A total of 4,200 patients with OT were analyzed, mean age ranged from 7.3 to 65.1 year of age, with similar distribution by sex. The frequency of recurrences in patients with OT was 49% (95% CI 40%-58%), being more frequent in the South American population than in Europeans. Additionally, visual impairment was presented in 35% (95% CI 25%-48%) and blindness in 20% (95% CI 13%-30%) of eyes, with a similar predominance in South Americans than in Europeans. On the other hand, having lesions near the macula or adjacent to the optic nerve had an OR of 4.83 (95% CI; 2.72-8.59) for blindness, similar to having more than one recurrence that had an OR of 3.18 (95% CI; 1.59-6.38). Finally, the prophylactic therapy with Trimethoprim/Sulfamethoxazole versus the placebo showed a protective factor of 83% during the first year and 87% in the second year after treatment.

CONCLUSION

Our Systematic Review showed that clinical factors such as being older than 40 years, patients with de novo OT lesions or with less than one year after the first episode, macular area involvement, lesions greater than 1 disc diameter, congenital toxoplasmosis, and bilateral compromise had more risk of recurrences. Also, environmental and parasite factors such as precipitations, geographical region where the infection is acquired, and more virulent strains confer greater risk of recurrences. Therefore, patients with the above mentioned clinical, environmental, and parasite factors could benefit from using prophylactic therapy.

Ocular toxoplasmosis, an overview focusing on clinical aspects

Toxoplasma gondii is a widespread protozoan parasite infecting approximately one third of the world population. After proliferation of tachyzoites during the acute stage, the parasite forms tissue cysts in various anatomical sites and establishes chronic infection. Nowadays the nature of the interplay between the protozoan and its human host remains elusive. This is clearly evident in ocular toxoplasmosis, in which the parasite establishes an ambivalent relationship with the eye, manipulating the immune response and inducing variable initial lesions and further relapses. This review will focus on epidemiology and environmental, parasite and host related risk factors, clinical manifestations and laboratory findings, treatment and prophylaxis approaches in ocular toxoplasmosis. An image collection of patients referred to the Unit of Ophthalmology of Pisa's Hospital will be presented, too.

Treatment Strategy in Human Ocular Toxoplasmosis: Why Antibiotics Have Failed

Background: There is currently no clear evidence of the effectiveness of antibiotic therapy in acute ocular toxoplasmosis (OT), but its effect as a secondary prophylaxis is undisputed. The majority of uveitis specialists advocate treatment. This meta-analytic review aims to critically analyze determinants of treatment success and to update current treatment strategies for OT in order to explain this discrepancy. Methods: A systematic literature search was performed in NCBI/PubMed, Clinical Trials, Google Scholar and ScienceDirect to retrieve pro- and retrospective studies using the key terms “ocular toxoplasmosis” or “retinochoroiditis” and “immunocompetent” and “treatment” or “therapy” and “human.” Of these, larger case series and prospective clinical studies and cross references identified from meta-analyses were selected by a manual search, and primary and secondary outcome parameters were extracted. Results: Ten case series and clinical trials reported success parameters for treatment outcomes, and four additional for recurrence prophylaxis. Five treatment studies were randomized clinical trials, three comparative and two noncomparative case series. Though several outcome parameters were reported, five of them defined time to healing, four visual gain and one lesion size as primary and secondary outcome parameters, recurrence rate as a secondary outcome parameter was reported once. No conclusive evidence was found for an antibiotic treatment effect. Four prophylaxis studies addressed the prevention of recurrences after treatment. The primary outcome in all studies was the effect of treatment and prophylaxis on recurrences, and all four found a significant effect on the risk of and time to recurrences. Conclusions: Antibiotic treatment of OT aims at controlling parasite proliferation. The absence of an effect on visual acuity and time to healing is thus not surprising. The fact that time to and number of recurrences respond to recurrence of prophylaxis proves the antibiotic effect on parasite activity.

Clinical and Biological Factors Associated With Recurrences of Severe Toxoplasmic Retinochoroiditis Confirmed by Aqueous Humor Analysis

PURPOSE

To investigate clinical and biological factors influencing recurrences of severe toxoplasmic retinochoroiditis (TRC) confirmed by aqueous humor analysis.

DESIGN

Retrospective case series.

METHODS

Retrospective analysis of 87 subjects with severe TRC, proven by positive Goldmann-Witmer coefficient (GWC), Toxoplasma gondii (T. gondii) immunoblot, or T. gondii-specific polymerase chain reaction (PCR) in aqueous humor. Cases with immunosuppression or retinal scars without previous recorded episode were excluded. Time-dependent, clinical, treatment-related, and biological factors were explored by univariate and multivariate shared frailty survival analyses.

RESULTS

Among 44 included subjects (age, 40.4 ± 17.6 years; follow-up, 8.3 ± 2.7 years), 22 presented recurrences. There was 0.11 recurrence/patient/year and mean disease-free interval was 5.0 ± 2.9 years. The risk of recurrence was higher immediately after an episode (P < .0001). Among recurrent cases, the risk of multiple recurrences was higher when the first recurrence occurred after longer disease-free intervals (P = .046). In univariate analysis, the recurrence risk declined with higher number of intense bands on aqueous T. gondii immunoblot (P = .006), and increased when venous vasculitis was present initially (P = .019). Multivariate analysis confirmed that eyes with more intense bands on immunoblot had fewer recurrences (P = .041). There was a near-significant risk elevation after pyrimethamine/azithromycin treatment (P = .078 and P = .054, univariate and multivariate). Intravenous corticosteroid administration, oral corticosteroid administration, aqueous GWC, and T. gondii PCR did not influence recurrences (P = .12, P = .10, P = .39, and P = .96, respectively).

CONCLUSIONS

Recurrences of severe TRC are not random and may be influenced by clinical and biological factors possibly related to blood-retinal barrier alterations. These results may contribute to identifying biomarkers for TRC reactivation.

Anatomical and functional outcomes of pars plana vitrectomy for inflammatory epiretinal membrane surgery in healed toxoplasmosis infection

Epiretinal membrane over macula secondary to toxoplasmosis compromises vision. We describe the outcome of pars plana vitrectomy and epiretinal membrane removal after adequate treatment of acute infection. The average age of all four male patients was 36 years (range 20–60 years). Following surgery there was an average three or more lines visual acuity improvement, restoration of foveal contour with reduction in central macular thickness. One patient developed choroidal neovascular membrane postsurgery and was effectively treated with intravitreal bevacizumab. Surgery for ERM secondary to healed toxoplasmosis infection has good anatomical outcome and reasonable visual improvement, when the surgery is done in a quiet eye.

Decision-making and management of uveitic cataract

The visual outcome of uveitic cataract surgery depends on the underlying uveitic diagnosis, the presence of vision-limiting pathology and perioperative optimization of disease control. A comprehensive preoperative ophthalmic assessment for the presence of concomitant ocular pathology, with particular emphasis on macula and optic nerve involvement, is essential to determine which patients will benefit from improved vision after cataract surgery. Meticulous examination in conjunction with adjunct investigations can help in preoperative surgical planning and in determining the need for combined or staged procedures. The eye should be quiescent for a minimum of 3 months before cataract surgery. Perioperative corticosteroid prophylaxis is important to reduce the risk of cystoid macular edema and recurrence of the uveitis. Antimicrobial prophylaxis may also reduce the risk of reactivation in eyes with infectious uveitis. Uveitic cataracts may be surgically demanding due to the presence of synechiae, membranes, and pupil abnormalities that limit access to the cataract. This can be overcome by manual stretching, multiple sphincterotomies or mechanical dilation with pupil dilation devices. In patients <2 years of age and in eyes where the inflammation is poorly controlled, intraocular lens implantation should be deferred. Intensive local and/or oral steroid prophylaxis should be given postoperatively if indicated. Patients must be monitored closely for disease recurrence, excessive inflammation, raised intraocular pressure, hypotony, and other complications. Complications must be treated aggressively to improve visual rehabilitation. With proper patient selection, improved surgical techniques and optimization of peri- and post-operative care, patients with uveitic cataracts can achieve good visual outcomes.

OUTCOMES AFTER PARS PLANA VITRECTOMY FOR EPIRETINAL MEMBRANES ASSOCIATED WITH TOXOPLASMOSIS

PURPOSE

To evaluate outcomes and complications of pars plana vitrectomy in patients with epiretinal membrane secondary to toxoplasmic retinochoroiditis.

METHODS

Retrospective evaluation of the records of 14 patients who underwent pars plana vitrectomy for epiretinal membrane secondary to toxoplasmic retinochoroiditis. The best-corrected visual acuity, intraoperative and postoperative complications, and macular optical coherence tomography were analysed. All patients received postoperative prophylactic treatment with trimethoprim/sulfamethoxazole.

RESULTS

Fourteen patients, 5 men and 9 women, were included. Mean follow-up period after surgery was 6.07 ± 2.64 months. Preoperative mean best-corrected visual acuity was 20/200, and postoperative mean best-corrected visual acuity was 20/60. There were no intraoperative complications. Three patients developed posterior capsule opacification, and one patient developed cataract.

CONCLUSION

Pars plana vitrectomy is a safe and effective procedure in patients with epiretinal membrane secondary to toxoplasmic retinochoroiditis, improving both visual acuity and anatomical result on macular optical coherence tomography. The most frequent postoperative complications were posterior capsule opacification and cataract. No recurrences of the disease were recorded.

Ocular toxoplasmosis: background and evidence for an antibiotic prophylaxis

PURPOSE OF REVIEW

The purpose of this review was to provide an overview of current data on antibiotic prophylaxis in ocular toxoplasmosis.

RECENT FINDINGS

Studies showing the prophylactic effect of long-term antibiotics are discussed. Prophylaxis seems to be justified in patients with a high risk of recurrence because of antibiotic's potential side-effects. Therefore, predisposing factors leading to a higher risk of recurrence and the time period during which an antibiotic prophylaxis is most appropriate are reviewed. Finally, a patient-individualized treatment recommendation is summarized.

SUMMARY

In the current literature, two prospective, randomized case-control studies exist, which show the protective effect of an antibiotic prophylaxis. Hematologic, gastrointestinal and dermatologic complications are potential side-effects. Especially during the first year after suffering a recurrence, an antibiotic prophylaxis seems to be justified. The risk of a recurrence is inter alia influenced by the duration of the disease, the immune status of the host and the patient's age. Therefore, an antibiotic prophylaxis should be considered for patients who have recently been infected with ocular toxoplasmosis, for middle-aged and elderly patients and patients with a compromised immune system. This should be discussed with each patient individually, especially if the lesion is close to the macula.