Multimodal Imaging in Ocular Toxoplasmosis

Serous macular detachment in ocular toxoplasmosis: A review

Ocular toxoplasmosis, a disease of the eye caused by the protozoan parasite Toxoplasma gondii, represents a common cause of posterior uveitis. The Authors review the current Literature regarding the uncommon presentation of ocular toxoplasmosis as macular serous retinal detachment (SRD). It is imperative to keep in mind that inflammatory SRD is a possible presentation of toxoplasmic retinochoroiditis. Underestimation of this clinical scenario and treatment with steroids alone without appropriate antiparasitic drugs, could lead to devastating consequences.

Ocular Toxoplasmosis

INTRODUCTION

Ocular toxoplasmosis is the leading cause of posterior uveitis worldwide, affecting individuals acrossdifferent age groups. The key to reducing vision loss includes prompt diagnosis and treatment. However, despite the prevalence of ocular toxoplasmosis, there has been little consensus regarding its pathophysiology,clinical features, diagnosis, and especially management.

METHODS

The data sources were literature reviews, including Pub Med and Medline databases. Search terms included toxoplasmosis, retinitis, vasculitis, vitritis, uveitis alone or in combination with, serum, aqueous, vitreous eye, ocular and review.

RESULTS

In this review paper, we have sought to provide an overview of the pathophysiology, epidemiology, and clinical features of the disease, both based on current literature and our own clinical experience. We have also discussed the use of serology, ocular fluid, and ophthalmic investigations that could further facilitate the diagnosis of ocular toxoplasmosis.Different management strategies have been reported worldwide, including newer approaches such as local therapy.

CONCLUSION

A better understanding of critical aspects of ocular toxoplasmosis will hopefully lead to reduced morbidity, including blindness associated with this condition.

A new perspective in the treatment follow-up of toxoplasma retinochoroiditis: Infiltrate thickness measurement

BACKGROUND

This study aimed to describe the spectral domain optical coherence tomography (SD-OCT) findings of active lesions in toxoplasma retinochoroiditis cases and to examine the changes in retinochoroidal infiltrate thickness after treatment.

METHODS

A total of 21 newly diagnosed patients with ocular toxoplasmosis were included in this prospective study. A complete ophthalmologic examination and SD-OCT were performed at the first visit. The patients were followed up weekly, and the SD-OCT images were taken over the lesion at each visit for 6 weeks. The characteristics of the active retinochoroiditis focus at the first visit were determined, and the infiltrate thicknesses at all visits were analyzed.

RESULTS

A statistically significant BCVA difference was observed at the first visit and at the last visit 6 weeks later (p < 0.01). The first week after treatment showed a significant decrease in infiltrate thickness (113.904 ± 86.001 µm). In the following weeks, this decrease continued more softly. The thickness change at 6 weeks was significantly reduced (16.095 ± 14.784 µm) compared with the previous ones. Weekly infitrate thickness changes were compared among themselves; a statistically significant difference was found between the 1st and 2nd weeks and the 5th and 6th weeks (p = 0.035 and p = 0.007, respectively). Detached posterior vitreous in 71% (15/21) and increased posterior vitreous thickness in 76% (16/21) of active lesion were detected. All patients had 100% (21/21) increased retinal reflectivity and disorganized retinal layers, and choroidal hypo-reflectivity was observed in 86% (18/21).

CONCLUSION

SD-OCT is a useful imaging modality in the diagnosis and follow-up of ocular toxoplasmosis cases. Serial thickness measurements of toxoplasma retinochoroiditis lesions may help confirm our diagnosis and determine the need for treatment.

Pediatric oral fluorescein angiography: a retrospective review from a single institution

PURPOSE

To describe our experience with locally developed evidence-based guidelines for oral fluorescein angiography (FA) for retinal imaging in children.

METHODS

The medical records of consecutive pediatric patients (≤18 years of age) at University of Pittsburgh Medical Center Children's Hospital Eye Center who underwent oral FA between November 1, 2018, and April 1, 2022, were reviewed retrospectively. Adherence to or deviation from the guidelines was noted at the time of testing.

RESULTS

A total of 55 patients aged 3-18 with 79 examinations were included. No patient was excluded from the retrospective case review because of lack of recorded data. The main indications for oral FA included uveitis, retinal vasculopathy, disk pathology, and retinal lesions. Three children had transient side effects, and 1 had delayed urticaria 4 hours after examination. No child had anaphylaxis. One patient had suboptimal imaging due to nonadherence to the guidelines-recommended fasting protocol. All other examinations (78/79), where guidelines were followed, provided images adequate for clinical decision making.

CONCLUSIONS

Based on our experience, we recommend that oral FA be considered, especially in children where intravenous access is less well tolerated while awake. Informed consent that includes the possibility of delayed side effects is advisable.

Outcome Measures for Disease Monitoring in Intraocular Inflammatory and Infectious Diseases (OCTOMERIA): Understanding the Choroid in Uveitis with Optical Coherence Tomography (OCT)

PURPOSE

To compare imaging modalities for the choroid of the eye, and evaluate various choroidal changes in uveitides entities.

METHODS

A comprehensive systematic literature review was conducted looking at current imaging modalities available to assess choroid architecture and commonly used parameters available to qualify and quantify choroidal changes, before looking at specific uveitides entities with choroidal involvement which have been broadly separated into non-infectious and infectious in etiology.

RESULTS

We describe the various modalities currently available to evaluate the choroid of the eye such as Ultrasound B Scan, ICGA, and OCT. Choroidal changes in various ocular and systemic diseases such as Behcet's Disease, Sarcoidosis, Syphillis, Tuberculosis, and many more have been reported and published.

CONCLUSION

Multiple choroidal tomographic and angiotomographic findings have been demonstrated for evaluation in uveitis. These findings can manifest in multiple ocular and systemic diseases, and can be illustrated using the various imaging modalities at present. Future advancements in choroidal imaging would help to adapt these findings into parameters for clinical practice to properly evaluate these ocular and systemic diseases.

Stepwise approach for fundus imaging in the diagnosis and management of posterior uveitis

An array of retinochoroid imaging modalities aid in comprehensive evaluation of the immunopathological changes in the retina and choroid, forming the core component for the diagnosis and management of inflammatory disorders such as uveitis. The recent technological breakthroughs have led to the development of imaging platforms that can evaluate the layers of retina and choroid and the structural and functional alteration in these tissues. Ophthalmologists heavily rely on imaging modalities such as dye-based angiographies (fluorescein angiography and indocyanine green angiography), optical coherence tomography, fundus autofluorescence, as well as dye-less angiography such as optical coherence tomography angiograph,y for establishing a precise diagnosis and understanding the pathophysiology of the diseases. Furthermore, these tools are now being deployed with a 'multimodal' approach for swift and accurate diagnosis. In this comprehensive review, we outline the imaging platforms used for evaluation of posterior uveitis and discuss the organized, algorithmic approach for the assessment of the disorders. Additionally, we provide an insight into disease-specific characteristic pathological changes and the established strategies to rule out disorders with overlapping features on imaging.

In vitro and in vivo anti−Toxoplasma activities of HDAC inhibitor Panobinostat on experimental acute ocular toxoplasmosis

Ocular toxoplasmosis (OT) is retinochoroiditis caused by Toxoplasma gondii infection, which poses a huge threat to vision. However, most traditional oral drugs for this disease have multiple side effects and have difficulty crossing the blood-retinal barrier, so the new alternative strategy is required to be developed urgently. Histone deacetylases (HDAC) inhibitors, initially applied to cancer, have attracted considerable attention as potential anti-Toxoplasma gondii drugs. Here, the efficacy of a novel HDAC inhibitor, Panobinostat (LBH589), against T. gondii has been investigated. In vitro, LBH589 inhibited the proliferation and activity of T. gondii in a dose-dependent manner with low toxicity to retinal pigment epithelial (RPE) cells. In vivo, optical coherence tomography (OCT) examination and histopathological studies showed that the inflammatory cell infiltration and the damage to retinal architecture were drastically reduced in C57BL/6 mice upon treatment with intravitreal injection of LBH589. Furthermore, we have found the mRNA expression levels of inflammatory cytokines were significantly decreased in LBH589–treated group. Collectively, our study demonstrates that LBH589 holds great promise as a preclinical candidate for control and cure of ocular toxoplasmosis.

Distinguishing swept-source optical coherence tomography findings in active toxoplasmic retinochoroiditis

OBJECTIVE

To define the swept-source optical coherence tomography (SS-OCT) features which distinguish ocular toxoplasmosis (OT) from other forms of retinochoroiditis.

METHODS

This is a prospective diagnostic study enrolling 43 eyes of 43 patients with active toxoplasmic (TOXO) retinochoroiditis matched to 54 eyes (54 lesions) with non-TOXO retinochoroiditis evaluated by structural SS-OCT.

RESULTS

The finding of retinal hyper-reflective round deposits, sub-lesional choroidal thickening, and sub-lesional retinal pigment epithelium elevation were more likely to be found in TOXO lesions with a positive likelihood ratio of 45.2 (95% CI: 6.45-316.56), 23.86 (95% CI: 6.09-93.36), and 9.79 (95% CI: 4.22-22.7), respectively. The presence of each of these findings was associated with a high level for positive predictive value (PPV) (88.63-97.29), negative predictive value (NPV) (88.3-92.45), sensitivity (83.72-90.69), and specificity (90.74-98.14). Two-parameter model binary logistic regression suggested that sub-lesional retinal pigment epithelium elevation and sub-lesional choroidal thickening were significant predictors of the diagnosis of OT (Wald = 11.905, p < 0.001; Wald = 14.881, p < 0.001; respectively). By adding hyper-reflective round deposits along the posterior hyaloid or the retinal surface the model improved its performance with very good diagnostic accuracy with area under the curve (AUC) values of 0.96 (95% CI: 0.9-0.99) for two parameters model and 0.98 (95% CI: 0.93-0.99) for the three parameters model.

CONCLUSIONS

Our results show that three OCT findings including retinal hyper-reflective round deposits, sub-lesional choroidal thickening, and sub-lesional retinal pigment epithelium elevation are more likely to occur in OT patients as compared with non-OT patients.

Optical Coherence Tomography Findings in Infectious Posterior Uveitis

PURPOSE

To describe and illustrate the main optical coherence tomography (OCT) findings of infectious uveitis.

METHODS

Narrative review.

RESULTS

Posterior segment OCT in patients with infectious uveitis reveals posterior hyaloid face precipitates, superficial retinal precipitates and infiltrates, foveolitis, retinitis, neuro-retinitis, choroidal granulomas, and choroiditis as main imaging biomarkers. Some of these features are specific to the underlying causing etiology and may support the diagnosis and the initiation of treatment. Some OCT features disappear completely with resolution; some others are associated with irreversible retinal damage.

CONCLUSIONS

OCT identifies different features of infectious uveitis into the vitreous, the retina, and the choroid. OCT characteristics, combined with other multimodal imaging features, are helpful in the differential diagnosis of infectious uveitis, the early detection of complications, and the assessment of the response to 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.

Recent Advances in Diagnosis and Treatment of Infectious Uveitis Prevalent in Asia-Pacific Region

ABSTRACT

The role of infections in intraocular inflammation is being increasingly recognized across the world. The Asia-Pacific region, being the single largest and most populous geographical entity on the planet, is home to a wide variety of such infections. Not surprisingly, there has been an explosion in the literature on infectious uveitis emerging from Asia-Pacific countries. In this review, we have covered recent advances in the diagnosis, treatment, and pathogenesis of common forms of infectious uveitis from the Asia-Pacific region. Much of the literature is focussed on the diagnosis of these infections by clinical criteria and laboratory investigations. There has also been an increased emphasis on the application of newer modes of ocular imaging and understanding pathomechanisms of ocular inflammation in these infections. Together this research has significantly improved our understanding of the diagnosis and management of infectious uveitis.