Toxoplasma gondii: an atypical presentation of toxoplasma as optic disc swelling and hemispherical retinal vein occlusion treated with intravitreal clindamycin

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.

Clinical outcomes of intravitreal treatment for ocular toxoplasmosis: systematic review and meta-analysis

BACKGROUND

Ocular toxoplasmosis is the leading cause of infectious posterior uveitis worldwide, accounting for 30-50% of all cases in immunocompetent patients. Conventional treatment is associated with adverse effects and does not prevent recurrence. Intravitreal drug administration can improve disease outcomes and reduce side effects. Herein, we conducted a systematic review and meta-analysis on the efficacy of intravitreal injections for treating ocular toxoplasmosis.

METHODS

The systematic search was conducted using PubMed, SciELO, and Google Scholar with the descriptors "ocular toxoplasmosis" AND "intravitreal". We analyzed studies that met the inclusion criteria, i.e., experimental cases in patients treated intravitreally for ocular toxoplasmosis. Considering the systematic review, we focused on the number of intravitreal injections, the therapeutic drug class, and the presence of preexisting conditions. To assess the efficacy of intravitreal injections, a meta-analysis was performed using visual acuity, side effects, disease recurrence, and inflammatory responses as variables.

RESULTS

Intravitreal injection-induced side effects were rarely observed (0.49% [0.00, 1.51%] ). The use of antiparasitic and anti-inflammatory drugs afforded improved visual acuity (99.81% [98.60, 100.00%]) and marked effectiveness in treating ocular toxoplasmosis.

CONCLUSIONS

Intravitreal injections may facilitate the successful treatment of ocular toxoplasmosis. However, clinicians should carefully evaluate the presence of preexisting conditions for ocular toxoplasmosis or previous diseases, as these can impact the decision to administer intravitreal injections.

<p>Intravitreal Clindamycin as First-Line Therapy for Toxoplasmic Retinochoroiditis: A Case Series</p>

Purpose

Materials and Methods

Results

Conclusion

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.

Design and development of intraocular polymeric implant systems for long-term controlled-release of clindamycin phosphate for toxoplasmic retinochoroiditis

BACKGROUND

The release of the anti-toxoplasmosis drug, clindamycin phosphate, from intraocular implants of the biodegradable polymers poly (D, L-lactic acid) (PLA) and poly (D, L-lactide-co-glycolide) (PLGA) has been studied in vitro.

MATERIALS AND METHODS

The preparation of the implants was performed by a melt-extrusion method. The developed extrudates were characterized and compared in in-vitro release profiles for elucidating the drug release mechanism. The formulations containing up to 40% w/w of drug were prepared. Release data in phosphate buffer (pH 7.4) were analyzed by high performance liquid chromatography. The release kinetics were fitted to the zero-order, Higuchi's square-root, first order and the Korsmeyer-Peppas empirical equations for the estimation of various parameters of the drug release curves. Degradation of implants was also investigated morphologically with time (Scanning Electron Microscopy).

RESULTS

It was observed that, the release profiles for the formulations exhibit a typical biphasic profile for bulk-eroding systems, characterized by a first phase of burst release (in first 24 hrs), followed by a phase of slower release. The duration of the secondary phase was found to be proportional to the molecular weight and monomer ratio of copolymers and also polymer-to-drug ratios. It was confirmed that Higuchi and first-order kinetics were the predominant release mechanisms than zero order kinetic. The Korsmeyer-Peppas exponent (n) ranged between 0.10 and 0.96. This value, confirmed fickian as the dominant mechanism for PLA formulations (n ≤ 0.45) and the anomalous mechanism, for PLGAs (0.45 < n < 0.90).

CONCLUSION

The implant of PLA (I.V. 0.2) containing 20% w/w of clindamycin, was identified as the optimum formulation in providing continuous efficient in-vitro release of clindamycin for about 5 weeks.

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.

Presumed toxoplasmic central retinal artery occlusion and multifocal retinitis with perivascular sheathing

Central retinal artery occlusion (CRAO) and multifocal retinitis with perivascular sheathing are rare in ocular toxoplasmosis. We report a case of toxoplasmic CRAO and multifocal retinitis with perivascular sheathing. A healthy 83-year-old male developed left panuveitis. Funduscopic examination of the left eye showed a swollen optic disc and sheathing of the retinal artery with a dense vitreous haze and a white retinal lesion. Serum anti-toxoplasma antibodies were positive in a latex agglutination assay. Vitrectomy was performed to improve visualization of the retinal lesions and for examination of causative microorganisms. A postoperative fundus examination revealed CRAO with optic disc involvement and multifocal retinitis with perivascular sheathing. Qualitative multiplex polymerase chain reaction detected the Toxoplasma gondii B1 gene in ocular fluid from both the aqueous and vitreous humor. The presumed diagnosis of ocular toxoplasmosis was made and treatment was started with prednisone and acetylspiramycin with subsequent improvement. Two months later, the patient developed active retinochoroiditis in the left eye. After 6 weeks of anti-toxoplasma therapy, the disease involuted. Retinal vascular occlusions and multifocal retinitis with perivascular sheathing are rare in toxoplasmosis. This is the first case report of toxoplasmic CRAO and multifocal retinitis with perivascular sheathing. The diagnosis of ocular toxoplasmosis should be considered in patients with retinal artery occlusions and multifocal retinitis with perivascular sheathing associated with inflammation.

Importance of nonenteric protozoan infections in immunocompromised people

There are many neglected nonenteric protozoa able to cause serious morbidity and mortality in humans, particularly in the developing world. Diseases caused by certain protozoa are often more severe in the presence of HIV. While information regarding neglected tropical diseases caused by trypanosomatids and Plasmodium is abundant, these protozoa are often not a first consideration in Western countries where they are not endemic. As such, diagnostics may not be available in these regions. Due to global travel and immigration, this has become an increasing problem. Inversely, in certain parts of the world (particularly sub-Saharan Africa), the HIV problem is so severe that diseases like microsporidiosis and toxoplasmosis are common. In Western countries, due to the availability of highly active antiretroviral therapy (HAART), these diseases are infrequently encountered. While free-living amoebae are rarely encountered in a clinical setting, when infections do occur, they are often fatal. Rapid diagnosis and treatment are essential to the survival of patients infected with these organisms. This paper reviews information on the diagnosis and treatment of nonenteric protozoal diseases in immunocompromised people, with a focus on patients infected with HIV. The nonenteric microsporidia, some trypanosomatids, Toxoplasma spp., Neospora spp., some free-living amoebae, Plasmodium spp., and Babesia spp. are discussed.

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.