Ocular Findings Aid in Diagnosis of West Nile Virus.

Introduction: West Nile virus disease, which is endemic to the United States, is a rarely reported systemic infection that can be difficult to diagnose. Chorioretinitis is an uncommon manifestation of West Nile virus but has pathognomonic ocular findings that can aid in diagnosis.

Case presentation: A 66-year-old man presented with acute onset fever, chills, and dyspnea. He underwent an extensive but nondiagnostic workup during hospitalization. New visual complaints prompted ophthalmology consultation. Funduscopic examination showed macular hemorrhages and midperipheral chorioretinal lesions. Fluorescein angiography revealed target-like lesions in a radial distribution, which is pathognomonic for West Nile virus chorioretinitis. Serology confirmed the diagnosis of West Nile virus disease. Systemic and ocular symptoms improved with supportive care.

Discussion: West Nile virus disease has many nonspecific manifestations. History of recent mosquito exposure is not always readily elicited. In patients with visual symptoms, eye examination can help in its diagnosis.

Conclusions: West Nile virus should be considered in patients with acute febrile or neurological illness during mosquito season.