Systemic and Ophthalmic Manifestations of West Nile Virus Infection

Yos Priestley; Marcia Thiel; Steven B. Koevary

Disclosures

Expert Rev Ophthalmol. 2008;3(3):279-292. 

In This Article

Differential Diagnosis of Ophthalmic Disease

Many of the ocular symptoms of WNV infection are associated with numerous viral, bacterial and parasitic diseases: highlighting the importance of differential diagnosis in confirming WNV infection. Patient history is an important first step in settling on a diagnosis of WNV. Previous exposure to mosquitoes or current mosquito bites associated with other systemic symptoms of WNV infection, such as fever, malaise, fatigue, headache, nausea and rash, supports inclusion of WNV in the differential diagnosis.

The most common ocular finding in WNV infection is chorioretinal lesions, which were shown in a small study to have 100% specificity and 73% sensitivity for the diagnosis of WNV infection in patients with suspected WNV compared with WNV-negative patients.[75] This said, of course chorioretinal lesions are not pathognomonic for WNV. Differential diagnosis of WNV chorioretinitis includes presumed ocular histoplasmosis syndrome (POHS), idiopathic multifocal choroiditis (IMC), Vogt-Koyanagi-Harada syndrome, Rift Valley fever, rubella, subacute sclerosing panencephalitis, sarcoidosis, syphilis and tuberculosis.[29,60,62,72] IMC and POHS commonly occur in young populations while WNV is more commonly seen in older individuals. Lesions in patients with IMC generally show hyperflourescence rather than hypofluorescence in the acute phase when observed with FA.[72] Clinical features of POHS do not include cells in the anterior or posterior chamber, unlike WNV chorioretinitis. Additionally, the lesions observed in patients with POHS are associated with peripapillary pigmentary changes and maculopathy.[29] In sarcoidosis, lesions are nodular granulomas, range in size from one-fourth to 1 disk diameter, and are found in clusters in the inferior retina.[29,76] Syphilis is most easily differentiated based on its systemic and neurological findings. In addition, lesions associated with syphilis are midzonal, sectoral and are associated with perivasculitis.[29,77] Unlike WNV lesions that appear and resolve together, the lesions in syphilis are recurrent and therefore found in different stages of resolution. Finally, chorioretinal lesions found in tuberculosis patients range from one-sixth to two disk sizes in diameter and have indistinct borders.[29,78]

Other ocular manifestations of WNV, such as anterior uveitis, vitritis and vasculitis, have multiple causes. Some conditions that should be considered include tuberculosis, syphilis, sarcoidosis, collagen vascular diseases, herpes viruses, Epstein-Barr virus, Lyme disease, Rift Valley fever, Behçet disease, rubella, rickettsioses and subacute sclerosing panencephalitis.[60,73,76,77,78]

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