Unilateral Toxoplasma retinochoroiditis with frosted branch angiitis: a multimodal imaging study

A woman in her late 30s presented with sudden diminution of vision, redness and pain in the right eye (OD) of 10 days' duration. Best corrected visual acuity (BCVA) was 20/160 in OD and 20/20 in the left eye (OS). Anterior segment of OD showed keratic precipitates, flare 3+, cells 2+ and a festooned pupil. Vitreous haze and cells were seen in OD. Frosted branch angiitis (FBA) was seen in all quadrants in OD and old Toxoplasma scar was seen in both eyes. Serum toxoplasma immunoglobulin G (IgG) was positive and IgM negative, and PCR of an aqueous humour sample was negative for Toxoplasma She was diagnosed with toxoplasa retinochoroiditis in OD and treated with intravitreal clindamycin injections, oral anti-Toxoplasma antibiotics and steroids. Three months later, her BCVA in OD was 20/40 with resolving inflammation. She presented 2 months later with a new focus of retinochoroiditis without FBA and an old Toxoplasma scar.

Active toxoplasma chorioretinitis in immunocompromised patients: a case series

Toxoplasma chorioretinitis (TC) can exhibit atypical features in immunocompromised patients including bilaterality, extensive spread, multifocal presentation, large areas of retinal necrosis without adjacent retinal scarring, and diffuse necrotizing retinitis resembling the viral retinitis that may cause confusion in the differential diagnosis. The aim of this study was to present the clinical features of four eyes of three immunocompromised patients with active toxoplasma chorioretinitis. Two of the patients were female and one, male. Two patients had hematological malignancies and the remaining patient was under adalimumab treatment for ankylosing spondylitis. Visual complaints began 10 days to four months prior to TC diagnosis. All four eyes had mild-to-moderate anterior chamber cells together with severe vitritis on slit-lamp examination while there were solitary chorioretinitis lesions on fundoscopy. Despite all patients were negative for anti-toxoplasma immunoglobulin M, all were positive for immunoglobulin G. All three patients were successfully treated with a combined treatment of systemic and intravitreal anti-toxoplasmic drugs. Clinicians should be cautious for the possible toxoplasma chorioretinitis besides the other infectious entities when a new uveitis episode is detected in an immunosuppressed patient in order to avoid misdiagnosis and thereby wrong treatment.

Ocular toxoplasmosis: a review of the current diagnostic and therapeutic approaches

PURPOSE

This review aims to summarize the current knowledge concerning the clinical features, diagnostic work-up and therapeutic approach of ocular toxoplasmosis focusing mainly on the postnatally acquired form of the disease.

METHODS

A meticulous literature search was performed in the PubMed database. A supplementary search was made in Google Scholar to complete the collected items.

RESULTS

Ocular toxoplasmosis is one of the most frequent infectious etiologies of posterior uveitis. It typically presents with retinochoroiditis. Setting an accurate diagnosis depends to a considerable degree on detecting characteristic clinical characteristics. In addition to the evaluation of clinical features, the diagnosis of toxoplasmosis relies at a large degree on serologic testing. The detection of the parasite DNA in the aqueous or vitreous humor can provide evidence for a definitive diagnosis. The current mainstay for the treatment, if necessary, is the use of oral antibiotic with systemic corticosteroids. Recent evidence suggests other therapeutic approaches, such as intravitreal antibiotics can be used.

CONCLUSION

Recent developments in the diagnostic and therapeutic approach have contributed to preventing or limiting vision loss of patients suffering from ocular toxoplasmosis. Further studies are required to provide a better understanding of epidemiology, pathogenesis, diagnosis, and treatment with a significant impact on the management of this challenging clinical entity.

Macular Infarction following Intravitreal Clindamycin Injection : A Case Report

Purpose

To report a case of Toxoplasma retinochoroiditis that was complicated by macular infarction following intravitreal clindamycin injection.

Methods

A 32-year-old otherwise healthy woman with the diagnosis of reactivation of Toxoplasma retinochoroiditis in her right eye, underwent intravitreal clindamycin injection. Shortly after injection, the visual acuity deteriorated, and the fundus examination revealed an extensive area of macular necrosis accompanied by vascular occlusion.

Results

The patient was observed. Unfortunately, the condition did not improve over time and resulted in a large area of retinal atrophy.

Conclusion

Macular infarction should be considered a rare but disastrous complication that can result in severe, irreversible visual loss.

[Intravitreal clindamycin injection in toxoplasma retinochoroiditis: About 9 cases in the ophthalmology department of the CHU de Bordeaux]

INTRODUCTION

Toxoplasma retinochoroiditis (TRC) is the main cause of posterior uveitis in immunocompetent patients. Several studies have shown safety and efficacy of treatment with intravitreal clindamycin injection in patients with contraindications, inadequate response or side effects with classic oral therapy. The goal of this study is to describe anatomic and functional results of local treatment with intravitreal clindamycin injection.

MATERIALS AND METHODS

We performed an observational, retrospective, single-center study in the ophthalmology service of Bordeaux university medical center between December 2017 and January 2020 on management of toxoplasma retinochoroiditis by intravitreal clindamycin injection. We analyzed the efficacy of this treatment on improvement in visual acuity, decrease in size of the retinal lesion and decrease in macular thickness.

RESULTS

A total of 10 eyes of 9 patients were injected. Only a single injection was required in 9 of the 10 cases. Injections demonstrated improvement in the 3 study criteria; visual acuity went from a mean of 1 LogMAR (1.07±0.77) pre-injection to 0.4 LogMAR (0.43±0.53) at 6 months, lesion size decreased by 51%, and macular thickness decreased by 78μm over the follow-up period.

CONCLUSION

Intravitreal clindamycin injections are safe and effective for the treatment of TRC. They offer an alternative in patients with allergies, side effects or inadequate response to classic oral therapy.

Use of a slow-release intravitreal clindamycin implant for the management of ocular toxoplasmosis

Purpose

To report the first patient with ocular toxoplasmosis treated with a slow-release biodegradable intravitreal clindamycin implant.

Observations

A 39-year-old human immunodeficiency virus (HIV)-positive woman with recurrent toxoplasmic retinochoroiditis and vitritis for whom oral medication was medically contraindicated was treated with an intravitreal slow-release clindamycin implant and three monthly intravitreal injections of clindamycin and dexamethasone. Serial ophthalmologic examinations demonstrated gradual, complete resolution of posterior uveitis and healing of the retinochoroidal lesion with cicatricial changes, as well as gradual improvement of cells in the anterior chamber. There was no significant change in electroretinography waves after treatment with the implant. The presence of the implant, or part of it, was detectable in the vitreous cavity for 4 months. To date, the patient has been monitored for 30 months, and there has been no reactivation of ocular toxoplasmosis.

Conclusion

The slow-release clindamycin implant was safe for intravitreal use in this patient and may have contributed to the long-term control of toxoplasmosis chorioretinitis.

Treatment of Toxoplasmosis: Historical Perspective, Animal Models, and Current Clinical Practice

Primary Toxoplasma gondii infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by tachyzoites, while tissue cysts characterize latent disease. Infection in the fetus and in immunocompromised patients can cause devastating disease. The combination of pyrimethamine and sulfadiazine (pyr-sulf), targeting the active stage of the infection, is the current gold standard for treating toxoplasmosis, but failure rates remain significant. Although other regimens are available, including pyrimethamine in combination with clindamycin, atovaquone, clarithromycin, or azithromycin or monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) or atovaquone, none have been found to be superior to pyr-sulf, and no regimen is active against the latent stage of the infection. Furthermore, the efficacy of these regimens against ocular disease remains uncertain. In multiple studies, systematic screening for Toxoplasma infection during gestation, followed by treatment with spiramycin for acute maternal infections and with pyr-sulf for those with established fetal infection, has been shown to be effective at preventing vertical transmission and minimizing the severity of congenital toxoplasmosis (CT). Despite significant progress in treating human disease, there is a strong impetus to develop novel therapeutics for both the acute and latent forms of the infection. Here we present an overview of toxoplasmosis treatment in humans and in animal models. Additional research is needed to identify novel drugs by use of innovative high-throughput screening technologies and to improve experimental models to reflect human disease. Such advances will pave the way for lead candidates to be tested in thoroughly designed clinical trials in defined patient populations.

Intravitreal Clindamycin and Dexamethasone Combined with Systemic Oral Antitoxoplasma Therapy versus Intravitreal Therapy Alone in the Management of Toxoplasma Retinochoroiditis: A Retrospective Study

Purpose

To compare clinical outcome of IVCD combined with oral therapy with IVCD alone in patients with toxoplasmic retinochoroiditis.

Patients and Methods

Thirty eyes were reviewed. Two equal groups were identified (15 eyes each). Clinical outcome measures were resolution of active inflammation, changes in BCVA and CMT, adverse drug reactions, and rate of recurrence.

Results

Mean baseline of BCVA 1.08 ± 0.17 and 1.03 ± 0.15 improved to 0.64 ± 0.18 and 0.69 ± 0.17 at the end of follow-up in group I and II, respectively. No statistically significant difference was observed. CMT was 392.6 ± 33.16 μm and 397.3 ± 14.6 μm significantly decreased to 314.7 ± 4.43 μm and 319.6 ± 7.8 μm. Resolution of acute inflammation was achieved in all cases in both groups. There were no recurrent cases in group I, and only one out of 15 (6.7%) in group II. No ocular or systemic adverse events were recorded.

Conclusion

IVCD is an effective route of treatment for active toxoplasmic retinochoroiditis that can be used solely without the need to use systemic medications..

Infectious chorioretinitis in an immunocompetent patient: A diagnostic dilemma

A 44-year-old male presented with a history of defective vision in the right eye for the past 5 months with the previous history of tubercular cervical lymphadenitis. On examination, right eye revealed panuveitis with dense vitritis and chorioretinitis in the superotemporal quadrant. His Mantoux test was positive (25 mm × 25 mm induration), QuantiFERON-TB Gold was test positive, aqueous aspirate was positive for Mycobacterium tuberculosis genome, negative for viruses and toxoplasma, and hence he was initiated on four-drug antitubercular therapy (ATT) with oral steroids. On follow-up, he had worsening of vitritis and intravenous methylprednisolone was given suspecting paradoxical reaction to ATT; however, a repeat AC tap was positive for toxoplasma B1 genome, IgG antitoxoplasma antibody was also positive in serum and aqueous; hence, we switched to systemic antitoxoplasma therapy. He underwent a therapeutic vitrectomy along with intravitreal clindamycin and dexamethasone for persistent vitreous membranes and vitritis. The patient responded well to the treatment with a reduction in vitritis and scarring of the lesion.

Safety of intravitreal clindamycin in albino rabbit eyes

PURPOSE

To study the potential toxic effects of intravitreal clindamycin on the retina of albino rabbits, by assessing functional and morphological retinal changes.

METHODS

Eight albino rabbits were included in the study. In each rabbit, 1 mg/0.1 ml clindamycin was injected into the vitreous of the right (experimental) eye, and 0.1 ml saline was injected into the vitreous of the left (control) eye. The electroretinogram (ERG) was recorded before injection, 3 days, 1, 2, and 4 weeks post-injection. The visual evoked potential (VEP) was recorded 4 weeks post-injection. Clinical examination was conducted at all time points. The eyes were enucleated at the termination of the follow-up period in order to prepare the retinas for histology in order to assess retinal structure.

RESULTS

ERG and VEP responses that were recorded from the experimental eye at different times following intravitreal clindamycin injection were very similar to the corresponding responses that were recorded from the control eyes. Clinical examination was normal in all eyes, and no histological damage was observed.

CONCLUSIONS

Intravitreal injection of 1 mg clindamycin does not cause functional or morphological signs of retinal toxicity in albino rabbits, during a period of 4 weeks post-injection. These findings support the clinical use of 1 mg intravitreal clindamycin.

Ocular safety of Intravitreal Clindamycin Hydrochloride Released by PLGA Implants

BACKGROUND

Drug ocular toxicity is a field that requires attention. Clindamycin has been injected intravitreally to treat ocular toxoplasmosis, the most common cause of eye posterior segment infection worldwide. However, little is known about the toxicity of clindamycin to ocular tissues. We have previously showed non intraocular toxicity in rabbit eyes of poly(lactic-co-glycolic acid) (PLGA) implants containing clindamycin hydrochloride (CLH) using only clinical macroscotopic observation. In this study, we investigated the in vivo biocompatibility of CLH-PLGA implants at microscotopic, cellular and molecular levels.

METHODS

Morphology of ARPE-19 and MIO-M1 human retinal cell lines was examined after 72 h exposure to CLH-PLGA implant. Drug delivery system was also implanted in the vitreous of rat eyes, retinal morphology was evaluated in vivo and ex vivo. Morphology of photoreceptors and inflammation was assessed using immunofluorescence and real-time PCR.

RESULTS

After 72 h incubation with CLH-PLGA implant, ARPE-19 and MIO-M1 cells preserved the actin filament network and cell morphology. Rat retinas displayed normal lamination structure at 30 days after CLH-PLGA implantation. There was no apoptotic cell and no loss in neuron cells. Cones and rods maintained their normal structure. Microglia/macrophages remained inactive. CLH-PLGA implantation did not induce gene expression of cytokines (IL-1β, TNF-α, IL-6), VEGF, and iNOS at day 30.

CONCLUSION

These results demonstrated the safety of the implant and highlight this device as a therapeutic alternative for the treatment of ocular toxoplasmosis.

Corticosteroids as adjuvant therapy for ocular toxoplasmosis

BACKGROUND

Ocular infection caused by Toxoplasma gondii, a parasite, may result in inflammation in the retina, choroid, and uvea, and consequently lead to complications such as glaucoma, cataract, and posterior synechiae.

OBJECTIVES

The objective of this systematic review was to assess the effects of adjunctive use of corticosteroids to anti-parasitic therapy versus anti-parasitic therapy alone for ocular toxoplasmosis.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register (2016; Issue 11)), MEDLINE Ovid, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, MEDLINE Ovid Daily (January 1946 to December 2016), Embase (January 1980 to December 2016), Latin American and Caribbean Literature on Health Sciences (LILACS (January 1982 to December 2016)), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP; www.who.int/ictrp/search/en). We used no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 7 December 2016.

SELECTION CRITERIA

We had planned to include randomized and quasi-randomized controlled trials. Eligible trials would have enrolled participants of any age who were immunocompetent and were diagnosed with acute ocular toxoplasmosis. Included trials would have compared anti-parasitic therapy plus corticosteroids versus anti-parasitic therapy alone, different doses or times of initiation of corticosteroids.

DATA COLLECTION AND ANALYSIS

Two authors independently screened titles and abstracts retrieved through the electronic searches. We retrieved full-text reports of studies categorized as 'unsure' or 'include' after we reviewed the abstracts. Two authors independently reviewed each full-text report for eligibility. Discrepancies were resolved through discussion.

MAIN RESULTS

We identified no completed or ongoing trial that was eligible for this Cochrane review.

AUTHORS' CONCLUSIONS

Although research has identified a wide variation in practice regarding the use of corticosteroids, our review did not identify any evidence from randomized controlled trials for or against the role of corticosteroids in the management of ocular toxoplasmosis. Several questions remain unanswered by well-conducted randomized trials in this context, including whether the use of corticosteroids as an adjunctive agent is more effective than the use of anti-parasitic therapy alone; if so, when corticosteroids should be initiated in the treatment regimen (early versus late course of treatment), and what would be the best dose and duration of steroid use.

A prospective randomized trial of azithromycin versus trimethoprim/sulfamethoxazole in treatment of toxoplasmic retinochoroiditis

Purpose

To assess the efficacy of oral azithromycin in the treatment of toxoplasmic retinochoroiditis.

Methods

A randomized interventional comparative study was conducted on 14 patients with ocular toxoplasmosis who were treated with oral azithromycin and 13 patients who were treated with oral trimethoprim/sulfamethoxazole for 6–12 weeks. The achievement of treatment criteria in the two groups and lesion size reduction were considered as primary outcome measures.

Results

The resolution of inflammatory activity, decrease in the size of retinochoroidal lesions, and final best corrected visual acuity (BCVA) did not differ between the two treatment groups. The lesion size declined significantly in all patients (P = 0.001). There was no significant difference in the reduction of the size of retinal lesions between the two treatment groups (P = 0.17).

Within each group, there was a significant improvement in BCVA after treatment; BCVA increased by 0.24 logMAR in the azithromycin group (P = 0.001) and by 0.3 logMAR in the trimethoprim/sulfamethoxazole group (P = 0.001).

Conclusions

Drug efficacy in terms of reducing the size of retinal lesions and visual improvement was similar in a regimen of trimethoprim/sulfamethoxazole or azithromycin treatment. Therefore, if confirmed with further studies, therapy with azithromycin seems to be an acceptable alternative for the treatment of ocular toxoplasmosis.

Anti-Toxoplasma activity and impact evaluation of lyophilization, hot molding process, and gamma-irradiation techniques on CLH-PLGA intravitreal implants

Intraocular delivery systems have been developed to treat many eye diseases, especially those affecting the posterior segment of the eye. However, ocular toxoplasmosis, the leading cause of infectious posterior uveitis in the world, still lacks an effective treatment. Therefore, our group developed an intravitreal polymeric implant to release clindamycin, a potent anti-Toxoplasma antibiotic. In this work, we used different techniques such as differential scanning calorimetry, thermogravimetry, X-ray diffraction, scanning electron microscopy, and fourier-transform infrared spectroscopy to investigate drug/polymer properties while manufacturing the delivery system. We showed that the lyophilization, hot molding process, and sterilization by gamma irradiation did not change drug/polymer physical-chemistry properties. The drug was found to be homogeneously dispersed into the poly lactic-co-glycolic acid (PLGA) chains and the profile release was characterized by an initial burst followed by prolonged release. The drug profile release was not modified after gamma irradiation and non-covalent interaction was found between the drug and the PLGA. We also observed the preservation of the drug activity by showing the potent anti-Toxoplasma effect of the implant, after 24-72 h in contact with cells infected by the parasite, which highlights this system as an alternative to treat toxoplasmic retinochoroiditis.

Current Therapy of Acquired Ocular Toxoplasmosis: A Review

Caused by the parasite Toxoplasma gondii, ocular toxoplasmosis (OT) is the most common form of posterior infectious uveitis. Combined antiparasitic therapy is the standard treatment for OT, but several other schemes have been proposed. The purpose of the present study was to review the literature on the treatment of OT and provide ophthalmologists with up-to-date information to help reduce OT-related visual morbidity. In conclusion, no ideal treatment scheme was identified; currently prescribed therapeutic schemes yield statistically similar functional outcomes.

The role of intravitreal trimethoprim/sulfamethoxazole in the treatment of toxoplasma retinochoroiditis

The authors evaluate the role of intravitreal trimethoprim/sulfamethoxazole in the treatment of toxoplasma retinochoroiditis (TRC) in four patients. Intravitreal injection of trimethoprim/sulfamethoxazole 1.28 mg/0.08 mL with dexamethasone 400 µg/0.1 mL was injected weekly or biweekly. After the initiation of treatment, a reduction in intraocular inflammation was observed clinically and on optical coherence tomography within 1 week. Three patients regained visual acuity of 20/20, and one patient improved to 20/40 with residual macular scarring. No evidence of retinal toxicity was noted on full-field electroretinogram. Intravitreal trimethoprim/sulfamethoxazole and dexamethasone combination may be an alternative treatment strategy in patients with TRC.

Intravitreal clindamycin in the treatment of unresponsive zone one toxoplasmic chorioretinitis: a case report

Introduction:

The current study aimed to report a case of toxoplasma chorioretinitis resistant to standard treatments that dramatically responded to intravitreal clindamycin injection.

Case Presentation:

A 23-year-old woman with the diagnosis of ocular toxoplasmosis in the left eye was initially treated by oral pyrimethamine, sulfadiazine, azithromycin and oral prednisolone. Since the treatment was unsuccessful intravitreal clindamycin (1 mg/ 0.1 mL) was injected. Responding dramatically, visual acuity improved from hand motion to 20/60 and 20/20, after seven days and six weeks, respectively. Anterior chamber and vitreous reactions were resolved.

Conclusions:

Intravitreal injection of clindamycin may be an acceptable alternative to the classic treatment in cases with refractory ocular toxoplasmosis. It may offer the patient more convenience, a safer systemic side effect profile, greater availability, and fewer follow-up visits and hematologic evaluations. Moreover, since it responds dramatically, it would be helpful in cases with involvement of macula or closeness to the optic nerve.

Development of a method to quantify clindamycin in vitreous humor of rabbits' eyes by UPLC-MS/MS: application to a comparative pharmacokinetic study and in vivo ocular biocompatibility evaluation

Ocular toxoplasmosis may result in uveitis in the posterior segment of the eye, leading to severe visual complications. Clindamycin-loaded poly(lactide-co-glycolide) (PLGA) implants could be applied to treat the ocular toxoplasmosis. In this study, the pharmacokinetic profiles of the drug administrated by PLGA implants and by intravitreal injections in rabbits' eyes were evaluated. The implant released the drug for 6 weeks while the drug administrated by intravitreal injections remained in the vitreous cavity for 2 weeks. Compared to the injected drug, the implants containing clindamycin had higher values of area under the curve (AUC) (39.2 vs 716.7 ng week mL(-1)) and maximum vitreous concentration (Cmax) (8.7 vs 13.83 ng mL(-1)). The implants prolonged the delivery of clindamycin and increased the contact of the drug with the eyes' tissues. Moreover, the in vivo ocular biocompatibility of the clindamycin-loaded PLGA implants was evaluated regarding to the clinical examination of the eyes and the measurement of the intraocular pressure (IOP) during 6 weeks. The implantable devices caused no ocular inflammatory process and induced the increase of the IOP in the fourth week of the study. The IOP augmentation could be related to the maximum concentration of clindamycin released from the implants. In conclusion, the PLGA implants based on clindamycin may be a therapeutic alternative to treat ocular toxoplasmosis.

Corticosteroids as adjuvant therapy for ocular toxoplasmosis

BACKGROUND

Ocular infestation with Toxoplasma gondii, a parasite, may result in inflammation in the retina, choroid, and uvea and consequently lead to complications such as glaucoma, cataract, and posterior synechiae.

OBJECTIVES

The objective of this systematic review was to assess the effects of adjunctive use of corticosteroids for ocular toxoplasmosis.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to October 2012), EMBASE (January 1980 to October 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We searched the reference lists of included studies for any additional studies not identified by the electronic searches. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 11 October 2012.

SELECTION CRITERIA

We planned to include randomized and quasi-randomized controlled trials. Eligible trials would have enrolled participants of any age who were immunocompetent and were diagnosed with active ocular toxoplasmosis. Included trials would have compared anti-parasitic therapy plus corticosteroids versus anti-parasitic therapy alone, or different doses or times of initiation of corticosteroids.

DATA COLLECTION AND ANALYSIS

Two authors independently screened titles and abstracts retrieved from the electronic searches. We retrieved full-text articles of studies categorized as 'unsure' or 'include' after review of the abstracts. Two authors independently reviewed each full-text article. Discrepancies were resolved through discussion.

MAIN RESULTS

The electronic searches retrieved 368 titles and abstracts. We reviewed 20 full-text articles. We identified no trials eligible for inclusion in this systematic review.

AUTHORS' CONCLUSIONS

Although research has identified wide variation in practices regarding use of corticosteroids, our systematic review did not identify evidence from randomized controlled trials for the role of corticosteroids in the management of ocular toxoplasmosis. Several questions remain unanswered by well-conducted randomized trials in this context, including whether use of corticosteroids is more effective than use of anti-parasitic therapy alone, when corticosteroids should be initiated in the treatment regimen (early versus late course of treatment), and which dosage and duration of steroid use is best. These questions are easily amenable to research using a randomized controlled design and they are ethical due to the absence of evidence to support or discourage use of corticosteroids for this condition. The question of foremost importance, however, is whether they should be used as adjunct therapy (that is, additional) to anti-parasitic agents.

Ocular toxoplasmosis II: clinical features, pathology and management

The term, ocular toxoplasmosis, refers to eye disease related to infection with the parasite, Toxoplasma gondii. Recurrent posterior uveitis is the typical form of this disease, characterized by unilateral, necrotizing retinitis with secondary choroiditis, occurring adjacent to a pigmented retinochoroidal scar and associated with retinal vasculitis and vitritis. Multiple atypical presentations are also described, and severe inflammation is observed in immunocompromised patients. Histopathological correlations demonstrate focal coagulative retinal necrosis, and early in the course of the disease, this inflammation is based in the inner retina. For typical ocular toxoplasmosis, a diagnosis is easily made on clinical examination. In atypical cases, ocular fluid testing to detect parasite DNA by polymerase chain reaction or to determine intraocular production of specific antibody may be extremely helpful for establishing aetiology. Given the high seroprevalence of toxoplasmosis in most communities, serological testing for T. gondii antibodies is generally not useful. Despite a lack of published evidence for effectiveness of current therapies, most ophthalmologists elect to treat patients with ocular toxoplasmosis that reduces or threatens to impact vision. Classic therapy consists of oral pyrimethamine and sulfadiazine, plus systemic corticosteroid. Substantial toxicity of this drug combination has spurred interest in alternative antimicrobials, as well as local forms of drug delivery. At this time, however, no therapeutic approach is curative of ocular toxoplasmosis.

Therapy for ocular toxoplasmosis

PURPOSE

To review current evidence for the treatment of ocular toxoplasmosis (OT).

DESIGN

Narrative review and expert recommendations.

METHODS

Meta-analysis and selected original articles from the medical literature were reviewed critically. Expert recommendations were analyzed.

RESULTS

Numerous observational studies suggest a benefit of short-term antimicrobial therapy for toxoplasmic retinochoroiditis in immunocompetent patients, although its efficacy has not been proven in randomized clinical trials. A randomized clinical trial revealed that intermittent trimethoprim/sulfamethoxazole treatment could decrease the rate of recurrence in high-risk patients. Intravitreal injection of clindamycin and dexamethasone was an acceptable alternative to the classic treatment for OT in a randomized clinical trial.

CONCLUSIONS

Opinions about therapy differ and controversy remains about its type, efficacy, and length. Intravitreal therapy may be promising for OT. A recent description of the presence of parasitemia in patients with active and inactive ocular toxoplasmosis raises new questions that need to be explored.

Intravitreal clindamycin and dexamethasone for zone 1 toxoplasmic retinochoroiditis at twenty-four months

PURPOSE

To report the anatomic and functional outcomes of intravitreal clindamycin and dexamethasone for the treatment of zone 1 toxoplasmic retinochoroiditis (TRC). Patients had 1 or more of the following indications for local therapy: intolerance to oral medication, contraindication to oral medication because of pregnancy, lack of response despite oral antimicrobial treatment, or treatment with concomitant oral and local therapy to avoid or limit foveal or optic disc involvement.

DESIGN

Noncomparative, retrospective, multicentric interventional case series.

PARTICIPANTS

We reviewed the medical records of 12 consecutive patients (eyes) with posterior pole (zone 1) TRC who were treated weekly or every 4 weeks (during pregnancy) with intravitreal injections of clindamycin (1.5 mg/0.1 ml) and dexamethasone (400 microg/0.1 ml).

METHODS

Ophthalmic evaluation included Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA); assessment of central macular thickness (CMT); resolution of inflammation by optical coherence tomography (OCT), clinical examination, and fluorescein angiography; and assessment of adverse events. Patients were followed for 24 months.

MAIN OUTCOME MEASURES

Resolution of TRC, changes in BCVA, and OCT.

RESULTS

Resolution of TRC was achieved in all cases with a mean number of injections of 3.6 (range: 2-5 injections) with a mean interval of 15.5+/-4 days. At 24 months a significant reduction in CMT by OCT was observed, from 387.6+/-70.1 microm to 185.2+/-44.7 microm (P = 0.0004). Baseline BCVA was logarithm of the minimal angle of resolution (logMAR) 1+/-0.4 (20/200), which improved to 0.5+/-0.4 (20/63) (P = 0.002) at the end of follow-up. Ten eyes (83.3%) improved > or =2 ETDRS lines of BCVA, and 2 eyes (20%) remained stable at 24 months. One patient's vision was limited because of macular scarring. No ocular or systemic adverse events were observed. No recurrences at 24 months of follow-up were observed.

CONCLUSIONS

The combination of intravitreal clindamycin and dexamethasone was associated with resolution of zone 1 TRC and functional and anatomic improvement in patients who did not tolerate, had contraindications to, or did not respond to oral medications.

[Toxoplasmosis and pregnancy]

Toxoplasmosis is the most common etiology of posterior uveitis. Toxoplasma gondii infection during pregnancy means either primary infection and risk of congenital toxoplasmosis or acute retinochoroiditis in a pregnant woman (risk of transmission, severity of injuries, therapeutics). Ingestion or manipulation of raw or undercooked meat is responsible for most contaminations (one- to two-thirds) in pregnant women. Toxoplasmosis seroprevalence is high in Europe, up to 54 % in southern European countries. Primary prevention advice is proposed to immunocompetent pregnant women who are seronegative for toxoplasmosis. The risk of transplacental transmission congenital toxoplasmosis during pregnancy is analyzed. The ocular lesions include retinochoroiditis and a number of other lesions. The departments of ophthalmology and of parasitology of Croix-Rousse University Hospital (Hospices Civils de Lyon) is currently following one of the largest cohorts of children infected with T. gondii (430 children alive in 2005). Our overall transmission rate during primary infection was 30 %. Retinochoroiditis incidence was 24 % in our prospective cohort. During follow-up, recurrences appeared in 29 % of cases. Acute toxoplasmic retinochoroiditis in pregnancy could be a risk of transplacental transmission due to potential parasitemia. Practices in cases of suspected or proved congenital infection are discussed. The antiparasitic drugs authorized during pregnancy are azithromycin and pyrimethamine. Azithromycin can be used alone but an association with pyrimethamine during the second trimester is useful in case of macular threat.

Intravitreal injection of therapeutic agents

BACKGROUND

Intravitreal injection (IVI) with administration of various pharmacological agents is a mainstay of treatment in ophthalmology for endopthalmitis, viral retinitis, age-related macular degeneration, cystoid macular edema, diabetic retinopathy, uveitis, vascular occlusions, and retinal detachment. The indications and therapeutic agents are reviewed in this study.

METHODS

A search of the English, German, and Spanish language MEDLINE database was conducted. A total of 654 references spanning the period through early 2008 were individually evaluated.

RESULTS

The advantage of the IVI technique is the ability to maximize intraocular levels of medications and to avoid the toxicities associated with systemic treatment. Intravitreal injection has been used to deliver several types of pharmacological agents into the vitreous cavity: antiinfective and antiinflammatory medications, immunomodulators, anticancer agents, gas, antivascular endothelial growth factor, and several others. The goal of this review is to provide a detailed description of the properties of numerous therapeutic agents that can be delivered through IVI, potential complications of the technique, and recommendations to avoid side effects.

CONCLUSION

The IVI technique is a valuable tool that can be tailored to the disease process of interest based on the pharmacological agent selected. This review provides the reader with a comprehensive summary of the IVI technique and its multitude of uses.

Novel approaches to retinal drug delivery

Research into treatment modalities affecting vision is rapidly progressing due to the high incidence of diseases such as diabetic macular edema, proliferative vitreoretinopathy, wet and dry age-related macular degeneration and cytomegalovirus retinitis. The unique anatomy and physiology of eye offers many challenges to developing effective retinal drug delivery systems. Historically, drugs have been administered to the eye as liquid drops instilled in the cul-de-sac. However retinal drug delivery is a challenging area. The transport of molecules between the vitreous/retina and systemic circulation is restricted by the blood-retinal barrier, which is made up of retinal pigment epithelium and endothelial cells of the retinal blood vessels. An increase in the understanding of drug absorption mechanisms into the retina from local and systemic administration has led to the development of various drug delivery systems, such as biodegradable and non-biodegradable implants, microspheres, nanoparticles and liposomes, gels and transporter-targeted prodrugs. Such diversity in approaches is an indication that there is still a need for an optimized noninvasive or minimally invasive drug delivery system to the eye. A number of large molecular weight compounds (i.e., oligonucleotides, RNA aptamers, peptides and monoclonal antibodies) have been and continue to be introduced as new therapeutic entities. However, for high molecular weight polar compounds the mechanism of epithelial transport is primarily through the tight junctions in the retinal pigment epithelium, as these agents undergo limited transcellular diffusion. Delivery and administration of these new drugs in a safe and effective manner is still a major challenge facing pharmaceutical scientists. In this review article, the authors discuss various drug delivery strategies, devices and challenges associated with drug delivery to the retina.

INTRAVITREAL CLINDAMYCIN FOR TOXOPLASMIC RETINOCHOROIDITIS

PURPOSE

To report outcomes of off-label use of intravitreal clindamycin in the treatment of toxoplasmic retinochoroiditis.

METHODS

In a noncomparative, retrospective, interventional case series, we reviewed the charts of six consecutive patients with toxoplasmic retinochoroiditis who were treated with intravitreal injection of clindamycin (1.0 mg/0.1 mL) because of intolerance to or disease progression despite oral microbial treatment. The primary outcome measures were change in Snellen visual acuity, resolution of inflammation, and adverse events.

RESULTS

Injection of intravitreal clindamycin was associated with control of toxoplasmic retinochoroiditis and resolution of vitreous inflammation in all six patients. Five patients had improvement in visual acuity. One patient's vision was limited because of macular scarring. Four patients underwent concomitant pars plana vitrectomy (PPV) at the time of injection. One patient who had concomitant clindamycin injection and PPV developed a retinal detachment postoperatively.

CONCLUSION

Intravitreal clindamycin injection, alone or in conjunction with PPV, was associated with resolution of toxoplasmic retinochoroiditis in six patients.

[Recurrent toxoplasmic retinochoroiditis after clindamycin treatment]

PURPOSE

To evaluate the efficacy and safety of subconjunctival injections of clindamycin associated with oral corticotherapy in the treatment of toxoplasmic retinochoroiditis (TRC) and its effect on recurrence.

PATIENTS AND METHODS

This study investigated 21 patients (10 males and 11 females) who presented to an ophthalmological department from 1995 to 2000, aged 14-55 years (mean, 28 years), with unilateral TRC. They were treated with subconjunctival injections of clindamycin and systemic corticotherapy at a dose of 1 mg/kg/day. Clinical follow-up consisted of assessment of visual acuity and biomicroscopic fundus examination, completed by retinal angiography if necessary.

RESULTS

We observed clinical improvement in 68.75% of patients within 4 days and in all patients healing of the chorioretinal area within 1.6 months. During the follow-up period ranging from 6 to 52 months (mean, 22 months), there have been two recurrences (9%) over the first 18 months. Tolerance of the injections was good. Serious side effects were noted in two patients: one case of conjunctival necrosis and one case of corneal and conjunctival erosion.

CONCLUSION

In treating ocular toxoplasmosis, clindamycin appears to be a safe and effective substitute for the classic protocol (pyrimethamine-sulfadiazine, pyrimethamine-azithromycin), for which a 50% recurrence rate has been reported. It provides relatively good protection against recurrence and warrants testing in further controlled studies.

LIDOCAINE GEL ANESTHESIA FOR INTRAVITREAL DRUG ADMINISTRATION

PURPOSE

To describe the use of topical gel anesthesia for intravitreal injection drug delivery.

METHODS

The first group (n=12) of patients is a crossover group of patients who on separate occasions received intravitreal injections after both 2% lidocaine subconjunctival injection (SC) and 2% lidocaine topical gel anesthesia using 30-gauge needle. The second group (n=16) is a consecutive group of patients who received either SC (n=8) or gel (n=8) anesthesia before intravitreal injection of triamcinolone using 27.5-gauge needle. Descriptive and numerical pain analog scale was used to assess pain sensation.

RESULTS

: There was no difference in pain score between gel and SC within the first group (P=0.67, paired, nonparametric test) and no difference in pain score comparing patients who had either SC or gel anesthesia before 27.5-gauge intravitreal injections (P=0.82, unpaired t-test) in the second group. However, there were significant differences in incidence of chemosis (P<0.001) and subconjunctival hemorrhage (P<0.001) after injection versus gel anesthesia in both groups.

CONCLUSION

Anesthesia with lidocaine 2% gel provides satisfactory patient comfort for administration of intravitreal injection and causes less chemosis and hemorrhage than SC anesthesia.

Ocular manifestations of toxoplasmosis

PURPOSE OF REVIEW

The concepts of toxoplasmosis and its ocular manifestations in humans have thoroughly changed in the past 3 years. This review addresses new epidemiologic data, specifically the occurrence of ocular disease in postnatal infections, and puts the changed views on the frequency and pathogenesis of toxoplasmic ocular manifestations into historical perspective.

RECENT FINDINGS

Newly described clinical presentations are discussed together with their recent diagnostic possibilities. The new data on congenital or postnatal acquisition of infection and their importance for ocular involvement are presented as well as the high prevalence of 79% of recurrent disease in ocular toxoplasmosis, which cannot be prevented by short-term treatments. Recently published analyses of literature showed, unexpectedly, the lack of efficacy of short-term treatments for ocular disease as well as of the long-term prenatal treatments on fetal transmission rate and the severity of congenital disease.

SUMMARY

The recent guidelines for treatment are included together with the up-to-date recommendations for the treatment of ocular toxoplasmosis in the immunosuppressed host.

Noninvasive detection of ganciclovir in ocular tissue by Raman spectroscopy: implication for monitoring of drug release

Treatment of various pathological conditions in ophthalmology, such as cytomegalovirus (CMV) retinopathy and endophthalmitis, requires a local drug intervention rather than a systemic approach. Accurate knowledge of intraocular drug concentration can permit the ophthalmologist to maintain drug levels within the therapeutic levels necessary for an optimal prognosis, while preventing or minimizing toxicity associated with drug overdose.

PURPOSE

To develop a noninvasive/noncontact method for quantification of the local concentration of ganciclovir in the ocular media.

METHODS

An integrated CCD-based Raman spectroscopic system designed specifically for ophthalmic applications was used to noninvasively detect the presence of ganciclovir in the ocular media. Various known concentrations of ganciclovir were injected into the aqueous humor of rabbit eyes in a pilot study, in vivo. Raman spectra were then acquired by focusing an argon laser beam within the anterior chamber of the eye. The specific Raman signature of ganciclovir was assessed at several concentrations.

RESULTS

Spectral features unique to ganciclovir were identified and distinguished from those of ocular tissue. The amplitudes of the spectral peaks corresponding to ganciclovir exhibited a linear dependence on the local concentration of the drug in the anterior chamber of the eye.

CONCLUSION

Raman spectroscopy may offer an effective tool for the noninvasive assessment of the local concentration of ganciclovir in the ocular media. This technique offers the potential to determine both the amount and the rate of the drug release from implants designed to deliver antiviral drugs locally within the eye. The availability of such data could enable the ophthalmologist to improve treatment efficacy by avoiding premature or late surgical replacement of the implants.

Hypersensitivity reaction to intravitreal clindamycin therapy

A Caucasian woman presenting with recurrence of intra-ocular toxoplasmosis was given intravitreal clindamycin. She subsequently developed a hypersensitivity reaction in the form of a generalized erythematous rash. To the authors' knowledge, hypersensitivity reactions to an antibiotic given by the intra-vitreal route have not previously been reported.