Acute Syphilitic Posterior Placoid Chorioretinitis in a Saudi Patient.

A 37-year-old otherwise healthy male presented with paracentral scotoma in his right eye for 1 day with a history of having unprotected sex with multiple partners. The patient was diagnosed to have acute syphilitic posterior placoid chorioretinitis with multimodal imaging including spectral-domain optical coherence tomography and fundus fluorescein angiography. His condition improved after 2 weeks course of intravenous benzyl penicillin 1.2 g every 4 h in collaboration with infectious disease physician. Copyright:

Introduction

Acute syphilitic posterior placoid chorioretinitis (ASPPC) was first described by Gass et al. in 1990 as a distinctive ocular manifestation of syphilis. ASPPC typically presents in the macular area and is characterized by the presence of one or more yellowish placoid lesions in the outer retinal layer and retinal pigment epithelium (RPE).[1]

Spectral-domain optical coherence tomography (SD-OCT) findings in patients with ASPPC shows hyperreflectivity of the RPE with nodular elevations and loss of the ellipsoid zone (EZ)/interdigitation zone (IZ).[2] In most patients, vision improves, and these OCT abnormalities resolve when systemic antibiotics treatment are initiated.

Fundus fluorescein angiography (FA) typically shows a hypofluorescent central lesion in the early phase and progressive hyperfluorescence in the later phases; these changes are occasionally associated with leopard spotting.[3]

In this report, we present a case of syphilitic uveitis in an immunocompetent young man who initially presented to the emergency department at the King Khaled Eye Specialist Hospital (KKESH).

Case Report

A 37-year-old male presented to the emergency department of KKESH complaining of paracentral scotoma in the right eye for 1 day. The patient had no other ocular, systemic symptoms, or any previous similar attack. He was not taking any medications, and his medical and family history was unremarkable.

On further exploration of his sexual history, he reported having multiple unprotected sexual encounters in the past.

On ocular examination, his best-corrected visual acuity was 20/20 in each eye. Intraocular pressure was 14 mmHg bilaterally.

Slit-lamp examination findings of the anterior segment were normal in both eyes. Dilated fundus examination of the right eye showed large yellowish placoid lesion in the macular area associated with vasculitis involving the superotemporal arcade, and fundus examination in the left eye was unremarkable [Figure 1a and b].

Figure 1

(a) Color fundus of the right eye showing placoid lesion in macular area; (b) color fundus of left eye showing normal retina. (c) fundus autofluorescence showing hyper fluorescence; (d and e) showing early hyperfluorescence with mottling and late staining in the affected area; (f) hyper-reflectivity of the retinal pigment epithelium with nodular elevations and loss of the ellipsoid zone/interdigitation zone; (g) Humphrey visual field with arcuate scotoma at presentation

There were no systemic manifestations such as chancres, condylomalata, maculopapular rash, or lymphadenopathy.

Fundus FA showed early hyperfluorescence with mottling, and late staining in the affected area and vascular leakage corresponding to area of vasculitis, fundus autofluorescence revealed localized hyperautofluorescence in the area of the placoid lesion [Figure 1c–e].

OCT of the right eye demonstrated hyperreflectivity of the RPE with nodular elevations and loss of the EZ/IZ line [Figure 1f].

Both eyes underwent Humphrey visual field testing which showed arcuate scotoma in the right eye [Figure 1g] and normal study in the left eye.

Syphilis serology workup revealed reactive rapid plasma reagin test of 1:32 titer and positive treponemal-specific tests (treponemal pallidum antibody) confirming active infection. Other infectious screening tests, including tuberculosis (TB) and HIV, were negative.

A diagnosis of syphilitic posterior placoid chorioretinitis was confirmed, and the patient was treated with a 2-week course of intravenous benzyl penicillin, 1.2 g every 4 h in collaboration with infectious disease physician.

At 3-week follow-up, the patient reported significant improvement in symptoms, along with the disappearance of placoid lesions on fundoscopy and FA. OCT showed the resolution of RPE nodularity with restoration of photoreceptor lines. The arcuate scotoma noted on Humphrey visual field test resolved completely [Figure 2a–d]. Fundus autofluorescence showed reduction in the previously noted hyperautofluorescence [Figure 2c].

Figure 2

(a) Color fundus of the right eye after the treatment; (b) optical coherence tomographyof the right eye showing improvement in nodularity of retinal pigment epithelium with a more clearly defined photoreceptor line and regularity of external limiting membrane; (c) autofluorescence showing improvement of lesion in compare to previous figure at presentation; (d) Humphrey visual field showing complete resolution of scotoma after treatment

Discussion

Ocular syphilis manifests in the retina as superficial retinal precipitates, retinal detachment, acute syphilitic placoid posterior chorioretinopathy, papillitis, vasculitis, neuroretinitis, chorioretinitis, and retinitis.[4]

ASPPC is a rare manifestation of ocular syphilis. It has been described by Gass et al. as solitary or multifocal, macular or papillary, placoid yellow-white lesions at the level of outer retinal layer/RPE.[3] It can affect either immunocompromised patients as shown in cases reported by Gass et al. or immunocompetent patients, as in our case, which was also observed by Franco and Nogueira and Ji et al.[56]

The pathogenesis of ASPPC remains unknown. It has been postulated by de souza et al., there is a role of immunecomplex-mediated hypersensitivity as the underlying mechanism.[7] Similarly, Brito et al. demonstrated the high level of anti-beta 2 glycoprotein antibodies, apolipoproteins that bind to cardiolipin. These antibodies might cause focal choroidal thrombosis and impairment of outer retinal layers and RPE function.[8] Another explanation was suggested by Gass et al. that disseminated spirochetes may also be present around the RPE in the placoid lesions.

In our patient who was immunocompetent, the diagnosis was established based on the high clinical suspicion and good interpretation of ophthalmic imaging which elicited detailed sexual history which was not voluntarily reported by the patient. The differential diagnosis in our region includes Bejel disease (endemic syphilis), Behcet's disease (BD), TB, and brucellosis. Bejel disease is a nonvenereal infection caused by Treponema pallidum. The disease was endemic in the middle east; in Saudi Arabia, around 4.7% of the patients presenting to hospitals have positive syphilis test.[9] The clinical features include absent of primary lesion, lack of cardiac and neurological involvement with the presence of bone changes on radiological examination. Although the disease has a different clinical features and mood of transmission, it cannot be differentiated from venereal syphilis on serological basis. Previous report by Tabbara et al. showed around 76% of bejel disease patient presented with uveitis (anterior uveitis, chorioretinitis, or choroiditis).[9] However, ASPPC has not been reported in Bejel disease. Although our patient lacks systemic manifestation of BD, ocular BD may occur before systemic manifestations. Relevant to this case, outer retinal involvement in BD may occur and transient loss of photoreceptors lines has been reported.[10] However, nodular thickening of the RPE was not a feature on SD-OCT in BD. TB and brucellosis are great mimickers in our region but were ruled out by workup.

It is recommended that all patients diagnosed with ASPPC should be treated as neurosyphilis with 2 weeks parenteral penicillin. Delaying in the treatment may lead to permanent functional damage.[11] In our patient, the early recognition and initiation of anti-syphilitic treatment resulted in rapid anatomical and visual recovery.

Our case represents a rare presentation of ocular syphilis with unilateral posterior placoid chorioretinitis in the absence of any associated systemic signs in a healthy patient. To the best of our knowledge, there have been no similar cases reported in the Middle East area. Timely treatment helps to avoid its ocular and systemic complications.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.