Introduction:

Serpiginous choroiditis, also known as helicoid or geographic choroidopathy, is a rare, idiopathic inflammatory disease affecting the retinal pigment epithelium, outer retina, and the inner choroid. It is slightly more common in men between 30 and 70 years of age with no predilection for race. It usually occurs in otherwise healthy individuals.

Clinical Features:

The most common complaints are blurring of vision and central or paracentral scotomata, but occasionally it is diagnosed asymptomatically on routine examination. Anterior segment inflammation is usually mild, and the vitreous may be clear or show minimal inflammation. The disease can be classified on the basis of clinical presentation as:

Lesions most commonly start in the peripapillary region (Fig. 17.3.1). Active lesions are yellow to grayish with associated overlying retinal edema. These spread in a centripetal, helicoid, map-like or snake-like pattern, from the initial area of involvement. Active lesions become atrophic in weeks to months, with atrophy of the retinal pigment epithelium, choriocapillaris, and choroid. New lesions arise at the edge of the atrophic ones. Choroidal neovascularization, subretinal hemorrhage and serous retinal detachment can complicate the course. The disease is typically chronic and remitting with quiescent periods of up to several years between active episodes.

OCT Features:

The characteristic active lesion of serpiginous choroiditis shows hyper-reflectivity and thickening of the outer retina, and increased reflectance of the choroid. This has been referred to as the ‘waterfall’ effect (Fig. 17.3.2). There is also disruption of the photoreceptor inner and outer segment junction in both active and inactive lesions (Fig. 17.3.3).

Ancillary Testing:

Visual field examination reveals central or paracentral scotoma. Fluorescein angiography of the active lesions show early hypofluorescence and late hyperfluorescence in a typical geographic pattern. Retinal vessels may stain adjacent to the active lesions. Old lesions show window defects, and late staining (see Figs 17.3.1D–F). Indocyanine green angiography reveals choroidal non-perfusion (see Fig. 17.3.1C).

Fundus hyperautofluorescence provides a clear demarcation of the retinal pigment epithelium damage in acute lesions. Scarring of the lesions causes decreased autofluorescence.

Treatment:

Periocular and systemic corticosteroids have been used to treat acute episode and long-term steroid-sparing therapy such as cyclosporine, azathioprine, cyclophosphamide, interferon alpha-2a or infliximab are needed to prevent recurrence.