ABSTRACT
Serpiginous choroiditis (SC) is a rare, chronic, recurrent, progressive disease of unknown origin. The inflammatory process of SC can disrupt Bruch’s membrane, allowing occasional choroidal vascular growth, leading to significant visual loss even in the healed stages of the disease. Optical coherence tomography angiography (OCTA) can help in the detection of choroidal neovascular membrane (CNV), leading to a definitive diagnosis and thereby guide the initiation of intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment. We report herein two cases of SC complicated with a CNV detected with OCTA and treated with a series of anti-VEGF injections.
Introduction
Serpiginous choroiditis (SC), is a rare clinical entity characterized by irreversible damage primarily to the choriocapillaries and secondarily to the retinal pigment epithelium, the rest of the choroid, and the outer retina.1,2 Lesions typically appear in the peripapillary area, but may extend to the macula as well.2 The most common complication of SC is the development of choroidal neovascular membrane (CNV), which occurs in 10-35% of all cases.3,4
Optical coherence tomography angiography (OCTA) is a novel non-invasive imaging modality that detects flow changes in the choroid, enabling stratified vascular analyses. Compared to fluorescein angiography (FA), OCTA provides high-resolution digital images of the different vascular layers, including the choriocapillaries and choroidal vessels. As a result, OCTA contributes significantly to the identification and monitoring of chorioretinopathies and their related complications such as CNV.5,6,7,8,9,10
Within this context, we would like to present two cases of SC complicated with CNV, confirmed with OCTA, and treated with ranibizumab (Lucentis, Novartis, Greece).
Discussion
SC, first described by Hutchinson3 in 1900, is a rare, vision-threatening disease with a prevalence of between 0.2% and 5% of all uveitis cases. It affects individuals from 30 to 70 years old and presents with painless, blurred vision, metamorphopsias, and paracentral scotomas.4,11 Initially it is unilateral, with the majority of cases demonstrating fellow eye involvement within 5 years. Confirmed unilateral cases are most commonly reported from tuberculosis-endemic countries.11 Dilated fundus examination reveals asymmetric bilateral grayish-yellow lesions and mild inflammation of the vitreous body.4 Recurrences, usually symptomatic, occur at the edges of the scars.11 Interestingly, the interval between recurrences varies from weeks to years.4 When no macular scarring exists, significant improvement of visual acuity is expected, similar to patient 1 and OD of patient 2 in our report. When CNV progresses to macular scarring, the visual outcome is less fortunate (patient 2, OS). The literature suggests that inflammation is the primary cause of CNV following age-related macular degeneration and myopia. Both infectious and non-infectious pathomechanisms can lead to the development of CNV. Although the overall incidence of CNV in non-infectious uveitides is only 2%, its prevalence is significantly higher in multifocal choroiditis, punctate inner choroiditis, and SC, which present with choroidal neovascularization in 32-46%, 17-40%, and 10-25% of all cases, respectively.12,13 Especially in SC, CNV constitutes the most common complication. It typically originates from the border of the choroidal lesions inducing ischemia in the outer retina and inner choroidal layers.14 Taking into account that SC affects patients at their productive age, prompt diagnosis and treatment of SC-related CNV is of paramount importance to preserve visual capacity.7
It is known that among the prevalent theories regarding the pathogenesis of CNV is inflammatory-induced angiogenesis mediated by vascular endothelial growth factor (VEGF).6,12,15 It is no surprise then, that the anti-VEGF medications exert a beneficial impact on CNV. Furthermore, damage to the RPE and Bruch’s membrane complex caused by chronic inflammation enables these new capillaries to pass from the choroid to the sub-RPE and subretinal space.7,12,13 It should be mentioned that in patient 2, CNV in OD manifested prior to the characteristic clinical lesions of SC. To our knowledge, this is the first report of this peculiar incidence.
Contemporary imaging technologies contribute significantly to the diagnosis of SC and its related manifestations. OCTA is a non-invasive imaging modality that facilitates the diagnosis and management of retinal and choroidal diseases.3,18 Recently, El Ameen and Herbort9 reported a case of SC diagnosed by OCTA and concluded that OCTA could even substitute for indocyanine green angiography.
OCTA seems to be useful in the diagnosis of SC-related complications as well, since its associated lesions present diagnostic difficulties with FA.7 OCTA has excellent reproducibility, is non-invasive, and is easily performed in few minutes.14 Although the use of OCTA in the diagnosis of type 1 CNV in age-related macular degeneration has been widely studied, published reports referring to the detection of the same complication in uveitis are limited.7
Campos Polo et al.6 used OCTA for the detection of CNV and its response to anti-VEGF injections in SC. Aggarwal et al.10 reported that OCTA is a helpful diagnostic tool for the detection of type 1 CNV in patients with tuberculous serpiginious-like choroiditis TB-SLC when conventional multimodal imaging methods fail to assist in the diagnosis. Astroz et al.16 indicated the diagnostic superiority of OCTA over FA in the detection of inflammatory CNV. Furthermore, Karti and Saatci13 reported that OCTA is useful not only in the differentiation of CNV from active inflammatory lesions, but it is also able to picture the characteristic lesions of white dot syndromes.
Until recently, the treatment options for SC-related CNV were photocoagulation, photodynamic therapy, and surgical excision.15 However, today intravitreal anti-VEGF injections are considered to be the first line of treatment.7 In our reported cases, we used ranibizumab, which contributed to BCVA improvement and regression of the inflammatory CNV. Our outcomes suggest that this therapeutic intervention is promising. Further cohorts of patients with SC are needed in order to draw safer conclusions in this direction.
