Serpiginous Choroiditis with Ischemic Optic Neuropathy

Dear Editor,

Serpiginous choroiditis is an uncommon, chronically recurring inflammatory disease of unknown etiology that affects the choroid and retinal pigment epithelium. Associated fundus findings include retinal vasculitis,¹ branch vein occlusion, sensory retinal detachment, retinal pigment epithelial detachment, and optic disc and retinal neovascularization. The optic nerve is rarely affected, although neovascularization and papillitis have been described¹, ² and an optic neuropathy may develop in this context. When present, causes other than inflammation must be considered.

Here, we report the case of a 51-year-old male with a history of chronic hypertension, hypercholesterolemia, and smoking, suffering from a bilateral recurrent serpiginous choroiditis with foveal involvement in the left eye (VA 1/20) and good visual acuity in the right eye, who developed a sudden, painless and non-progressive visual loss (VA 1/10), accompanied by an afferent pupillary defect and optic disc edema in the right eye. The visual loss occurred two months after immunosuppressive therapy was started with methotrexate (10 mg/week) and prednisone (10 mg/day) on alternate days, as proposed by Hooper and Kaplan.³ He was diagnosed with anterior ischemic optic neuropathy (AION) in the right eye with no clinical activation of the serpiginous choroiditis, confirmed by FA. Visual field studies of the right eye revealed nerve bundle field defects, with scotomata corresponding to the quiescent lesions in his fundus. Fundus examination of the left eye did not demonstrate a crowded optic nerve head (a finding known to be associated with ischemic optic neuropathy). Examination of the right eye revealed a diffuse disc edema with peripapillary hemorrhages. Foci of inactive choroiditis were found close to the optic disc. Although intravenous bolus of methylprednisolone was given urgently, visual acuity recovered only slightly and optic atrophy developed a few months later.

Several different hypotheses could explain the development of ischemic optic neuropathy in this case. First, an inflammatory papillitis with secondary ischemia in the context of an active choroiditis may be considered. However, we believe this was not the case here since the patient did not show any sign of activity during the immunosuppressive therapy he was receiving, the serpiginous choroiditis was quiescent at the moment of the study, and no signs of retinal vasculitis were found (assessed by FA). Second, it could be a corticosteroid-induced optic neuropathy,⁴ although this is unlikely with such low doses of steroids.⁵ Finally, a coincidental nonarteritic ischemic optic neuropathy with a vaso-occlusive mechanism could be postulated. This last hypothesis seems to us the most probable, given the fact that the patient had chronic hypertension, hypercholesterolemia, and smoking habits, all important risk factors for microvascular disease. Additional potential causes of the optic neuropathy, such as infectious (post-herpes zoster ophthalmicus) or other underlying (sarcoidosis, polyarteritis nodosa, etc.) pathologies, were discarded based on the patient's clinical history. Steroid-induced diabetes, which could contribute to chronic edema, could also be discarded due to the low doses used and the normal levels of blood glucose measured on several occasions.

In very rare cases, an optic neuropathy may develop in the context of serpiginous choroiditis. In these instances, causes other than inflammation, such as chronic arterial hypertension, hypercholesterolemia, small cup-to-disk ratio, and infectious and auto-immune disorders, must be considered.