Chorioretinal involvement in patients with West Nile Virus infection

Purpose. To characterize and analyze the chorioretinal manifestations of West Nile virus (WNV) infection. Design: Prospective, noncomparative case series. Participants: Twenty-nine consecutive patients with serologically confirmed WNV infection in the setting of an outbreak of the disease. Methods: The average duration of systemic symptoms before ophthalmic examination was 10 days (range, 2-30 days). All participants underwent a detailed ophthalmic examination at presentation and regularly throughout follow-up, including dilated biomicroscopic fundus examination, fundus photography, and fluorescein angiography. Results: Atypical multifocal chorioretinitis was observed in 20 of 29 patients (69%) bilaterally at presentation and developed later during follow-up in 3 patients (10.3%), bilaterally (n = 1) or unilaterally (n = 2). Multifocal chorioretinitis was associated with mild vitreous inflammatory reaction in all cases. Other findings included intraretinal hemorrhages (21 patients [72.4%]), white-centered retinal hemorrhages (7 patients [24.1%]), focal retinal vascular sheathing (3 patients [10.4%]), marked diffuse retinal arterial sheathing (1 patient [3.4%]), retinal vascular leakage (5 patients [17.2%]), optic disc swelling (2 patients [6.9%]), optic disc staining (6 patients [20.7%]), segmental zones of retinal pigment epithelium changes (1 patient [3.4%]), and nonproliferative diabetic retinopathy (7 patients [24.1%]). The posterior segment findings related to WNV disease had a self-limited course in all patients. Conclusions: Chorioretinal involvement, frequently asymptomatic and self-limited, is common in patients with acute WNV infection. The unique pattern of multifocal chorioretinitis in patients with systemic symptoms suggestive of WNV can help to establish the diagnosis while serologic testing is pending. Therefore, a systematic ocular evaluation, including dilated fundus examination and fluorescein angiography in selected cases, is recommended in patients with clinically suspected WNV infection. (C) 2004 by the American Academy of Ophthalmology.