Serpiginous choroiditis is an acute, recurrent, progressive multifocal inflammatory disease of the inner choroid and RPE that subsequently involves the overlying retina. The sequential development of the typical pattern of contiguous, angulated, geographic-appearing chorioretinal lesions is pathognomonic. Inflammatory foci extend from the peripapillary area circumferentially and eventually involve the retinal midperiphery. New lesions appear as dull, white opacifications of the RPE that become depigmented as the lesions evolve and eventually develop RPE metaplasia. New lesions form adjacent to older ones in a stepwise fashion. The opposite eye is frequently involved, and the central fovea may be spared for long periods. Fluorescein angiography typically demonstrates nonfluorescent acute lesions in the early phases of the study; in the late phases, the edges of the lesions begin to stain due to leakage of fluid from the surrounding contiguous choriocapillaris. Eventually the central portion of the inflammatory lesions fills with fluorescein. Partially healed and chronic lesions eventually show loss of choriocapillaris and abnormal RPE with secondary relative hyperfluorescence on fluorescein angiography.
The color photograph of the right eye (Figure 6-4A) demonstrates dull, white multifocal confluent geographic lesions at the level of the RPE. The superior portion of the lesion (arrows) appears most acute and opaque, whereas the foveal area appears partially healed, with thinning of the RPE and choroid apparent on stereo photography.
The transit phase fluorescein angiogram (Figure 6-4B) demonstrates typical central hypofluorescence of the geographic lesion (arrow), with mild peripheral staining at the margins of the lesion. No acute hyperfluorescence consistent with choroidal neovascularization (CNV) is evident, and the central fovea appears to be involved.
This early recirculation phase stereo photograph (Figure 6-4C) confirms the location of the lesion at the level of the RPE and choroid, with the overlying retina appearing grossly normal. Some elevation of the subfoveal tissue is seen, implying that there may have been occult subfoveal neovascularization in the past (arrow). This may represent fibrous metaplasia of the RPE.
The late recirculation phase angiogram (Figure 6-4D) demonstrates granular central staining of the entire lesion, representing diffusion of dye late in the study from the surrounding healthy choriocapillaris. The borders of the lesion are relatively hyperfluorescent, an appearance typical for chronic tissue damage but not active CNV. No other areas of fundus appear to be involved, and the optic nerve appears grossly normal.
Treatment of this presumed nongranulomatous choroiditis is based on the strong probability of the development of CNV, particularly within the macula and adjacent to a previously healed serpiginous lesion. It may be difficult to differentiate the grayish discoloration of choroidal neovascular membrane (CNVM) formation from reactivation of a marginal lesion of serpiginous choroidopathy, but in the early transit phase, fluorescein angiography will demonstrate acute hyperfluorescence associated with CNVM that will not be present in recurrent serpiginous choroiditis. Laser photocoagulation is indicated for lesions outside the foveola. Some clinicians have treated active serpiginous choroiditis that is threatening the macula with systemic prednisone or acyclovir with variable results.
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