Cox’s Conference: Ocular syphilis as a manifestation of early neurosyphilis

Case:

This week’s Cox’s Conference Case was presented by Dr. Varun Sondhi and led by discussant, Dr. James Luby. 

The patient was a 50 year old man who presented with 3 months of progressive, painless, central vision loss in his right eye and 2-3 weeks of progressive vision loss in his left eye. He was noted to have a painless anal ulcer and was noted to have regular unprotected sex with multiple male partners. He was seen by ophthalmology, diagnosed with anterior uveitis. Laboratory testing revealed a negative HIV test and an RPR titer of 1:256. He was diagnosed with ocular syphilis as a manifestation of early neurosyphilis and treated with IV penicillin.

Discussion:

Neurosyphilis is an infection of the central nervous system by Treponema pallidum. It can occur at any stage of syphilis, primary, secondary, and tertiary. It occurs due to invasion of the cerebrospinal fluid (CSF). After invasion, persistent infection or spontaneous clearance (with or without transient meningitis) can occur. Ocular syphilis is a rare manifestation and can affect any part of the eye. The most common presentation is panuveitis. However, anterior uveitis, posterior uveitis, intermediate uveitis, interstitial keratitis, chorioretinitis, retinovasculitis, retinitis, papillitis, retrobulbar neuritis, optic atrophy, optic nerve gumma, and various stroke syndromes can also occur. Given the broad differential diagnosis of these findings, correlation with additional findings or history suggestive of syphilis is key in early diagnosis and treatement. In the aforemetioned patient, his anal ulcer and sexual history provided strong suspicion of syphilis as an etiology and expedited diagnosis and treatment. As was seen in our patient, ocular syphilis can occur in immunocompetent patients.

Ocular syphilis is treated in the same manner as neurosyphilis. CDC guidelines recommend aqueous crystalline penicillin G 18–24 million units per day, administered as 3–4 million units IV every 4 hours or continuous infusion, for 10–14 days. CSF fluid should be obtained even in asymptomatic patients.

Follow up should occur at least every six months after treatment. This should include repeat CSF fluid collection until pleocytosis resolves and CSF VDRL is negative. Failure of treatment is defined as failure to decrease CSF pleocytosis after six months, failure to resolve CSF pleocytosis or CSF protein elevation by two years, worsening of CSF pleocytosis, VDRL titers failing to decrease by at least four fold, or VDRL titers increasing by four fold. Retreatment should be then be highly considered. Note that one common cause of “treatment failure” is re-exposure.

References:

Am J Ophthalmol. 2015 Feb;159(2):334-343

Curr Opin Ophthalmol. 2014 Nov;25(6):513-8

https://www.cdc.gov/std/tg2015/syphilis.htm