Syphilitic outer retinopathy mimicking acute zonal occult outer retinopathy

Author: Almudena de-Pablo-Cabrera (Spain)

Co-authors: Javier Sambricio-García, Manuel Ferro-Osuna

Purpose

To present a case of syphilitic outer retinopathy mimicking acute zonal occult outer retinopathy.

Setting/Venue

Ophthalmology Department Hospital 12 de Octubre Madrid, Spain.

Methods

A 40-year-old man presented to our emergency department complaining of 1-week history of acute central scotoma and photopsias in his right eye (OD). Best corrected visual acuity (BCVA) was 20/50 in his OD and 20/20 in his left eye. Anterior segment was unremarkable in both eyes. Abnormal funduscopy was limited to OD which presented a subtle yellowish appearance of the retina on the posterior pole, with a subtle curvilinear demarcation line above the superior vascular arcade. There was no vitritis or vascular sheathing. Optical coherence tomography (OCT) was performed demonstrating a disruption of the outer retina, with loss of the inner-segment / outer-segment junction. Autofluorescence showed mild hyperfluorescence with a granular pattern, coinciding with the yellowish appearing retina. An electroretinogram (ERG) was also performed which revealed reduced amplitude in OD. As for other symptoms, the patient reported having skin lesions on his palms which were being treated by his dermatologist as an allergic reaction to chemical products used in his job. He denied any other symptoms or relevant medical history. On view of these findings a presumed diagnosis of acute zonal occult outer retinopathy (AZOOR) was made and laboratory testing including serologies were made to rule out other diagnosis.

Results

The patient was found to have a positive rapid plasma regain (RPR) (titer 1:64) and positive syphilis IgG. HIV testing was negative. He was then examined by Internal Medicine and revealed having similar skin lesions on his soles. In view of these results the patient was diagnosed with active syphilis with reaginic activity, ocular syphilis (syphilitic outer retinopathy) and skin lesions compatible with late syphilitic secundarism. He was admitted to receive intravenous treatment with Penicilin G for 10 days, as well as oral corticoisteroids (30 mg) in order to avoid a Jarisch Herxheimer reaction (JHR). On follow-up visit after completion of the treatment the patient’s BCVA had returned to 20/20 in OD. Funduscopy revealed almost normal appearance, and reconstitution of the inner-segment / outer-segment junction on OCT was noted, although with slight irregularities in some areas. Autofluorescence demonstrated reduced hyperautofluorescence. ERG was repeated and demonstrated normalized amplitude. Oral corticoidsteroids were tapered until suspension and two doses of intramuscular penicillin were administered as per protocol. On follow-up BCVA remained 20/20 and OCT continued to improve to complete normal appearance after two months. No recurrence has been evidenced after 8 months of follow-up.

Conlusions

Ocular syphilis can develop at any stage of the disease and can involve any ocular structure. It has no pathognomonic presentation, being able to mimic any type of inflammation, which often leads to misdiagnosis. As syphilitic involvement of the retina is considered a form of neurosyphilis, recommended treatment is intravenous penicillin. However, the pathophysiology of syphilitic outer retinopathy is unclear and some authors have reported good results with corticoisteroid treatment alone. Both a direct primary infection of the outer retina and an autoimmune reaction as a result of molecular mimicry are possible pathologic mechanisms. In addition, corticosteroids can be useful to avoid an inflammatory reaction to endotoxin products released by the death of the spirochetes when initiating antimicrobial treatment (JHR). This highlights the importance of anti-inflammatory treatment in addition to the antibiotic. In this case, our presumption diagnosis was AZOOR but we decided to do laboratory testing including serologies to rule out other possible diagnosis. Prompt treatment with Penicilin and corticosteroids permitted a rapid recovery of vision with excellent prognosis. The numerous ophthalmic presentations of syphilis should alert physicians to consider this disease as differential diagnosis of AZOOR-like presentations as this is crucial for early diagnosis and treatment.

Financial Disclosure

No financial disclosure.