Figure 1: The patient’s fundus photo shows vitreous haze partially obscuring multifocal linearly-arranged circular chorioretinal scars.
Figure 2: A fundus autofluorescence image demonstrates multifocal hyperautofluorescent scars in linear patterns.
Figure 3: This fluorescein angiography exam reveals multiple “target-like” lesions, each with a hyperfluorescent periphery and hypofluorescent center.
An 82-year-old female with a history of primary lung adenocarcinoma and type I diabetes presented to the emergency department with bilateral blurry vision.
The patient had recently been hospitalized twice for fever, headaches, and confusion, and she was treated with intravenous antibiotics without resolution. The patient subsequently developed progressively worsened blurred vision in the course of 2 weeks. Of note, the patient went on a trip to Aruba 3 months prior to the onset of her symptoms.
On examination, her Snellen visual acuities were 20/100 OD and 20/300 OS. Pupillary exam and intraocular pressures (IOP) were normal. The patient had decreased color vision in both eyes. Dilated fundus exam was notable for bilateral vitritis and multiple circular chorioretinal scars that were arranged in a linear pattern (Figure 1). Fundus autofluorescence (Figure 2) showed hyperautofluorescence of the lesions and fluorescein angiography (Figure 3) demonstrated target-like lesions with a hyperfluorescent ring around a hypofluorescent core. The patient underwent brain magnetic resonance imaging (MRI) which did not reveal any pathology.
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The clinical presentations of fever, headaches, and confusion, along with exam findings of vitritis and chorioretinal scars in linear configuration led to work up for West Nile virus (WNV) infection. The patient received a broad panel of infectious and inflammatory testing that revealed positive titers for serum WNV IgG, serum WNV IgM, and cerebrospinal fluid WNV IgG, confirming the diagnosis of West Nile virus-related posterior uveitis.
The WNV is a single-stranded RNA flavivirus transmitted by mosquitoes, though the reservoir is wild birds. After a 2 to 15 day incubation period, patients with WNV develop a febrile illness only 20% of the time, with the other 80% being asymptomatic subclinical disease.1 Common symptoms include fever, fatigue, malaise, gastrointestinal symptoms, and maculopapular rash. In 1% of cases, neuroinvasive disease develops which may cause meningoencephalitis, a poliomyelitis-like syndrome, weakness or paralysis.1
Among patients who develop ocular WNV infection, 80% will develop an asymptomatic multifocal chorioretinitis.2 For the remaining 20%, clinical signs include anterior uveitis, retinal vasculitis, optic neuritis, cranial nerve palsies, and linearly-arranged or scattered chorioretinal lesions which appear circular and creamy white when active though they transition to atrophic and pigmented circular spots when inactive.2
Treatment for WNV infection remains supportive, including hospitalization, intravenous fluids, and respiratory support. Ocular complications are usually self-limited with vision returning to baseline. However, persistent vision loss could occur if the disease is complicated by foveal chorioretinal scarring, choroidal neovascularization, vitreous hemorrhage, retinal detachment, or optic atrophy develop.3 In certain cases with choroidal neovascularization, anti-vascular endothelial growth factor (VEGF) therapy may be indicated. Systemically, most patients with non-neuroinvasive WNV disease recover completely, though patients with WNV encephalitis or poliomyelitis often have residual neurological deficits with a significantly higher mortality rate.4
- Davis LE, DeBiasi R, Goade DE, et al. West Nile virus neuroinvasive disease. Ann Neurol. 2006;60(3):286-300. doi:10.1002/ana.20959
- Garg S, Jampol LM. Systemic and intraocular manifestations of West Nile virus infection. Surv Ophthalmol. 2005;50(1):3-13. doi:10.1016/j.survophthal.2004.10.001
- Khairallah M, Ben Yahia S, Ladjimi A, et al. Chorioretinal involvement in patients with West Nile virus infection. Ophthalmol. 2004;111(11):2065-2070. doi:10.1016/j.ophtha.2004.03.03
- West Nile virus. Centers for Disease Control and Prevention website. http://www.cdc.gov/westnile/index.html. Updated July 7, 2021. Accessed May 24, 2022.