Posterior Segment Manifestations of Cat-scratch Disease: A Mini-review of the Clinical and Multi-modal Imaging Features

Bartonella henselae, an intracellular gram-negative bacillus, is usually transmitted from infected cats to humans by direct or indirect contact. The bacterium mainly infects erythrocytes and endothelial cells thereby leading to so called cat-scratch disease (CSD) and may present with various localised and/or systemic manifestations. The eye is the most commonly affected organ in disseminated CSD and ocular bartonellosis has been reported in 5-10% of CSD patients. The most well-known clinical feature of ocular bartonellosis is neuroretinitis but various sight-threatening posterior segment lesions involving the optic nerve, retinal vasculature, retinal and choroidal tissues may occur during the disease course. This mini-review aims to overview both the clinical and multi-modal imaging characteristics of posterior ocular segment manifestations of CSD.

VASCULARIZED SARCOID GRANULOMA COMPLICATED BY PLACOID DISEASE IN A PEDIATRIC PATIENT

PURPOSE

To report a case of pediatric vascularized sarcoid choroidal granuloma complicated by placoid-like inflammation.

METHODS

Case report.

RESULTS

A 10-year-old girl presented with blurry vision in her right eye and a yellowish macular lesion that had been diagnosed as fibrotic choroidal neovascular membrane and observed for several months. On referral to our clinic, optical coherence tomography revealed a homogeneous hyperreflective lesion obliterating the choroidal vasculature and protruding under the retina with associated subretinal and intraretinal fluid. Optical coherence tomography angiography revealed vascularization of this granulomatous lesion, and the girl underwent six intravitreal injections of anti-vascular endothelial growth factor, with reabsorption of the fluid and consolidation of the lesion. A sudden, abrupt decrease in the visual acuity of the right eye 3 months after the last injection was accompanied on optical coherence tomography by hyperreflective inflammatory lesions breaking from the retinal pigment epithelium and involving the outer nuclear layer, all around the fibrotic granulomatous lesion. The girl was treated with oral steroids, and an extensive systemic evaluation revealed hilar adenopathy, thus posing the diagnosis of pediatric sarcoidosis complicated by placoid chorioretinopathy.

CONCLUSION

Atypical presentations of typical uveitic diseases are quite common in children. The presence of a foveal vascularized granuloma complicated by a placoid disorder should prompt the exclusion of infectious etiologies such as tuberculosis, to establish a therapy to preserve the child's vision.

Longitudinal changes in retinal microvasculature after panretinal photocoagulation in diabetic retinopathy using swept-source OCT angiography

This study evaluated quantitative changes in microvascular parameters after panretinal photocoagulation (PRP) in diabetic retinopathy (DR), using swept-source OCT Angiography (SS-OCTA). A total of 27 treatment-naïve eyes were subjected to PRP and followed-up for > 12 months after the procedure. Foveal avascular zone (FAZ) area, macular perfusion density (PD), and vessel length density (VLD) were calculated on a 3 × 3 mm en face OCTA image and nonperfusion area (NPA) was obtained on a 12 × 12 mm en face OCTA image. One month after PRP, PD and VLD of superficial and deep capillary plexus decreased and subsequently, increased progressively across the next 12 months, with statistically significant differences (P = 0.015 and 0.02). Continuous decreasing trends in total NPA values was observed across 12 months after PRP (P = 0.125). A difference in PD of the superficial capillary plexus between baseline and 6 months post PRP, was significantly associated with the progression of DR, 12 months after PRP (OR 0.528; P = 0.025). We found significant longitudinal retinal microvascular changes after PRP in DR. Overall macular perfusion status was impaired and progressively recovered across the next 12 months, compared to the baseline. Additionally, the early treatment responses in PD can predict the long-term outcomes of PDR after PRP.

The broad spectrum of application of optical coherence tomography angiography to the anterior segment of the eye in inflammatory conditions: a review of the literature

Background

With an increased number of papers on how to interpret optical coherence tomography angiography (OCTA) findings in uveitis, the aim of this review is to assess its efficacy for the quantitative monitoring of structural and functional changes in inflamed conjunctiva and iris vessels in patients with acute anterior uveitis and iris neovascularization.

Main body

OCTA, currently designed as a retinal vascular imaging system, has been recently adapted for anterior segment and showed good potential for successful imaging of the conjunctiva, the cornea, and the iris. OCTA can successfully delineate corneal vessels with substantial image quality. At the same time, it can detect changes in conjunctival and limbal vascularization and thus can be applied to pseudo-inflammatory conditions such as pterygium. Anterior segment OCTA allows analysis of iris vasculature and 3-D reconstruction of the normal iris vessels. OCTA can determined iris vessel filling defects or their flow increase, when present, secondary to inflammatory conditions. In addition, OCTA gives qualitative vessel density values that can be compared pre- and post-anti-inflammatory treatment. OCTA for imaging of the iris vasculature in health and disease is highly dependent on iris pigmentation. In both OCTA and fluorescein angiography, iris pigmentation causes vasculature imaging blockage, but OCTA provides more detailed iris vasculature images. Fine, clinically invisible iris vessels can be visualized by OCTA in the very early stages as well as in the regressed stage of NVI. Additional studies including different iris pathologies are needed to determine the most optimal scanning parameters in OCTA of the anterior segment.

Conclusions

This review aims to establish the current application of OCTA to anterior segment disorders of the eye, with an emphasis on exploring its use in iris vessel dilation seen in various forms of iritis, as a predictive factor for further episodes of inflammation. In addition, OCTA can depict neovascularization of the iris secondary to proliferative diabetic retinopathy.

Optical coherence tomography angiography (OCTA) as a new diagnostic tool in uveitis

Background

The broad spectrum of uveitis disorders requires a multimodal imaging approach in the daily practice of an ophthalmologist. As inflammatory conditions, they have in common an alteration in leukocyte migration. In this context, optical coherence tomography angiography (OCTA) might be of great value for diagnosing or following up patients with these disorders. To date, OCTA has rather been used as an additional tool besides the well-established diagnostic imaging tools, but its complementary diagnostic features become increasingly relevant, to follow disease activity and treatment response and for the understanding of pathomechanisms of various uveitis types.

This review summarizes the possible applications of OCTA and its advantages and disadvantages as opposed to dye-based angiographies in uveitic diseases.

Main body

Hitherto gold standards in the diagnostic workup of posterior or intermediate uveitis have been angiography on a dye-based method, which is fluorescein or indocyanine green. It gives information about the status of the blood-retinal barrier and the retinal and choroidal vasculature by visualizing diffuse leakage as a state of inflammation or complications as an ischemia or choroidal neovascularization. As noninvasive methods, fundus autofluorescence depicts the status of metabolic activity of the retinal pigment epithelium and OCT or enhanced depth imaging OCT, respectively, as a depth-resolving imaging method can supply additional information.

OCTA as a non-invasive, depth-resolution imaging tool of retinal and choroidal vessels adds detailed qualitative and quantitative information of the status of retinal and choroidal vessels and bridges the gap between the mentioned conventional diagnostic tools used in uveitis.

It is important, though, to be aware of its limitations, such as its susceptibility to motion artifacts, limited comparability among different devices, and restricted contribution of information regarding the grade of disease activity.

Conclusion

OCTA as a non-invasive, depth-resolution imaging tool can give qualitative and quantitative information about the status of retinal and choroidal vessels, but also has certain limitations. Employing OCTA as a complementary rather than exclusive tool, it can give important additional information about the macro- and microvasculature under inflammatory circumstances. Thereby, it also contributes to the understanding of the pathophysiology of various uveitis entities.

An overview of optical coherence tomography angiography and the posterior pole

Optical coherence tomography angiography is a relatively new, noninvasive technology that has revolutionized imaging of the retinal and choroidal microvasculature. This technology is based on the detection of movement or changes that represent moving red cells in sequential optical coherence tomography scans. As with other established imaging technologies, it has unique benefits as well as certain disadvantages, which include a limited field of view and vulnerability to imaging artifacts. However, software and hardware improvements are continually evolving to mitigate these limitations. Optical coherence tomography angiography has been used to gain a better understanding of microvascular changes across a spectrum of ocular diseases including diabetic retinopathy, age-related macular degeneration, glaucoma, and retinal vein occlusions. In this article, we review algorithms and techniques commonly utilized in optical coherence tomography angiography systems and compare optical coherence tomography angiography to fluorescein angiography, the current gold standard for imaging the retinal vasculature. In addition, we provide an overview of important optical coherence tomography angiography findings in a variety of ocular diseases. Although the clinical role of this technology is still poorly defined, optical coherence tomography angiography has the potential to become an invaluable tool in the diagnosis and monitoring of vascular pathologies.

Ocular manifestations of bartonellosis

PURPOSE OF REVIEW

To review the systemic and ocular complications of Bartonella spp. infections specifically cat scratch disease, encompassing epidemiology, laboratory diagnostics, ophthalmic imagining, and treatment.

RECENT FINDINGS

Recent studies have shown that ocular manifestations occur in approximately 4.4% of cat scratch disease patients. The annual prevalence is lower than previously reported to be approximately 12 500 cases annually. Mainstay treatment continues to be oral antibiotics with and without corticosteroids and is dependent on associated systemic manifestations, age, and patient immune status. More recently anti-VEGF agents have been used for complications such as cystoid macular edema and choroidal neovascularization.

SUMMARY

Bartonella spp. infections continue to be a common cause uveitis with ophthalmic manifestations ranging from neuroretinits, vascular occlusions, to choroidal granulomas. Review of associated risk factors including contact with feline reservoirs will aid in recognition and diagnosis of this disease entity. Laboratory diagnostics continue to improve to help with the diagnosis of this entity.

Neuroretinitis: a review

PURPOSE OF REVIEW

Neuroretinitis is an inflammatory disorder of the eye presenting with optic disc edema and the delayed development of a macular star secondary to optic nerve swelling toward the macular structures. Neuroretinitis can be divided into idiopathic, infectious (including neuroretinitis associated with cat scratch disease) and recurrent.

RECENT FINDINGS

The clinical presentation of neuroretinitis includes impaired visual acuity, dyschromatopsia, relative afferent pupillary defects and visual field abnormalities - particularly cecocentral and central scotomas. Features suggesting recurrent neuroretinitis include poorer visual recovery and visual field abnormalities representing damage to greater parts of the optic nerve. Treatment of neuroretinitis is based upon the cause of the disease. Specifically, in patients with cat scratch neuroretinitis, visual recovery is often favorable regardless of treatment with medication. However, some authors favor treatment with antibiotics early in the course of disease to limit progression and ensure eradication of the organism.

SUMMARY

Neuroretinitis can result from a number of infectious and noninfectious causes and it is essential that clinicians recognize the disease and determine the underlying etiology to ensure the best possible treatment and visual prognosis for the patient.

Optical Coherence Tomography Angiography in Intermediate Uveitis

PURPOSE

To investigate the involvement of the retinal and choriocapillaris microvasculature in intermediate uveitis on optical coherence tomography angiography (OCT-A).

DESIGN

Case-control study.

METHODS

Patients and age-matched controls were imaged with swept-source OCT-A. Using ImageJ, superficial and deep retinal vasculature were semi-automatically analyzed for vessel (VD) and skeleton density (SD), vessel diameter index (VDI), and fractal dimension (FD). Choriocapillaris layer was automatically graded for mean signal intensity, signal intensity standard deviation, kurtosis of signal intensity distribution, and flow signal voids.

RESULTS

Twenty-nine intermediate uveitis eyes and 30 control eyes were included. Both superficial and deep retinal layers showed significant reduction in all OCT-A parameters (eg, superficial retinal layer: 0.31 vs 0.40 VD, 5.6e^-8 vs 6.4e^-8 SD, 5.4e⁶ vs 6.1e⁶ VDI, and 1.78 vs 1.79 FD, respectively, all P < .05). At the choriocapillaris layer a greater heterogeneity of perfusion with a shift toward a higher proportion of large confluent flow signal voids was present. Also in the absence of macular edema OCT-A parameters were reduced when compared with healthy controls (all parameters except for VDI in the superficial retinal layer and the choriocapillaris kurtosis and flow signal void analyses).

CONCLUSIONS

In intermediate uveitis, reduced vascular density and complexity in superficial as well as deep retinal layers and altered choriocapillaris perfusion are present. Moreover, these findings indicate impairment of the macular microvasculature even in the absence of macular edema. The results of our study may aid in the diagnosis as well as the monitoring of intermediate uveitis.

An update on inflammatory choroidal neovascularization: epidemiology, multimodal imaging, and management

Inflammatory choroidal neovascular membranes are challenging to diagnose and manage. A number of uveitic entities may be complicated by the development of choroidal neovascularization leading to a decrease in central visual acuity. In conditions such as punctate inner choroidopathy, development of choroidal neovascularization is extremely common and must be suspected in all cases. On the other hand, in patients with conditions such as serpiginous choroiditis, and multifocal choroiditis, it may be difficult to differentiate between inflammatory choroiditis lesions and choroidal neovascularization. Multimodal imaging analysis, including the recently introduced technology of optical coherence tomography angiography, greatly aid in the diagnosis and management of inflammatory choroidal neovascularization. Management of these neovascular membranes consists of anti-vascular growth factor agents, with or without concomitant anti-inflammatory and/or corticosteroid therapy.

Clinical applications of optical coherence tomography angiography: What we have learnt in the first 3 years

A review of the literature from 2014 to 2016 was conducted, focusing on the results of optical coherence tomography angiography in different chorioretinal diseases. In only 3 years, optical coherence tomography angiography has been shown to be an effective tool for diagnosing choroidal neovascularization complicating age-related macular degeneration, pathologic myopia, and inflammatory conditions. The technique has sometimes been considered superior to conventional multimodal imaging, for example, in choroidal neovascularization associated with chronic central serous chorioretinopathy or multifocal choroiditis. In retinal vascular diseases, optical coherence tomography angiography has helped to understand the condition described as paracentral acute middle maculopathy and has been considered highly effective for the analysis of retinal vascular macular changes secondary to retinal vein occlusion or macular telangiectasia. Changes in the foveal avascular zone, also reported in diabetic maculopathy, have been shown to occur before any angiographic signs. A reduction in capillary vascular density has been reported in the fovea of eyes with malignant melanoma, but not in eyes with choroidal nevus. However, optical coherence tomography angiography is a recent technique that probably needs refinements and further studies. Nevertheless, the first 3 years of optical coherence tomography angiography use suggest its clinical relevance and useful applications in daily clinical practice.

An overview of the clinical applications of optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) has emerged as a novel, non-invasive imaging modality that allows the detailed study of flow within the vascular structures of the eye. Compared to conventional dye angiography, OCTA can produce more detailed, higher resolution images of the vasculature without the added risk of dye injection. In our review, we discuss the advantages and disadvantages of this new technology in comparison to conventional dye angiography. We provide an overview of the current OCTA technology available, compare the various commercial OCTA machines technical specifications and discuss some future software improvements. An approach to the interpretation of OCTA images by correlating images to other multimodal imaging with attention to identifying potential artefacts will be outlined and may be useful to ophthalmologists, particularly those who are currently still unfamiliar with this new technology. This review is based on a search of peer-reviewed published papers relevant to OCTA according to our current knowledge, up to January 2017, available on the PubMed database. Currently, many of the published studies have focused on OCTA imaging of the retina, in particular, the use of OCTA in the diagnosis and management of common retinal diseases such as age-related macular degeneration and retinal vascular diseases. In addition, we describe clinical applications for OCTA imaging in inflammatory diseases, optic nerve diseases and anterior segment diseases. This review is based on both the current literature and the clinical experience of our individual authors, with an emphasis on the clinical applications of this imaging technology.