Acute Syphilitic Posterior Placoid Chorioretinitis

Published on 09/05/2015 by admin

Filed under Opthalmology

Last modified 22/04/2025

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Acute Syphilitic Posterior Placoid Chorioretinitis

Introduction:

Ocular syphilis is a rare manifestation of disease caused by the spirochete Treponema pallidum. Intraocular infection may be acquired during the secondary or tertiary stages of infection. This disease is most prevalent in the fifth decade of life in men. Of note, there is high correlation with co-infection with human immunodeficiency virus type 1.

Clinical Features:

Acute syphilitic posterior placoid chorioretinitis is a specific and characteristic manifestation of ocular syphilis. A singular or multiple yellow-colored, circular, deep retinal or choroidal plaques located in the macula are characteristically present. The lesions may be multifocal and subtle. Bilaterality occurs in about half of affected patients.

OCT Features:

Much like the disease itself, the OCT findings can vary. Focal loss of the external limiting membrane and IS–OS/ellipsoid zone are common, the retinal pigment epithelium layer may be abnormal, and choroidal infiltration with thickening may also be visible (Fig. 18.3.1). Serous retinal detachments involving the macula are uncommon, occurring in about 10% of cases.

Figure 18.3.1 OCT in acute syphilitic posterior placoid chorioretinitis shows involvement of the IS–OS layer. The IS–OS/ellipsoid zone is abnormally indistinct (between black arrowheads) and then drops out completely (to right of black arrowheads). The retinal pigment epithelium layer in the region of IS–OS/ellipsoid zone dropout is irregular. There is also focal loss of the external limiting membrane and infiltration of the inner choroid with thickening. The accompanying thickness map shows abnormal thickening of the parafoveal region, particularly nasally. (Courtesy of Robin A. Vora MD.)

Ancillary Testing:

Fluorescein angiography usually shows a central hypofluorescent area corresponding to the plaque, occasionally with leopard spotting early, followed by progressive hyperfluorescence later. Late staining from the retinal vessels and optic nerve, even outside areas of retinal whitening, is typical. Indocyanine green angiography typically shows hypofluorescence in both early and late stages.

Treatment:

Prompt treatment with intravenous penicillin G (24 million units daily for 14 days) is indicated. Testing should be performed for both human immunodeficiency virus and neurosyphilis.

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