Abstract
Purpose :
Despite an increased prevalence of syphilis, there is no consensus regarding best testing procedures to diagnose syphilitic uveitis. We reviewed test results for patients with non-specific uveitis at a tertiary care center to determine positive and negative predictive values (PPV, NPV) for non-treponemal (NT) and treponemal (TR) tests in this population.
Methods :
We reviewed medical records of all new patients with uveitis seen by 8 uveitis specialists during the period 2013-17 for age, sex, serologic test results, HIV status, uveitis category, and history of prior syphilis and treatment. Diagnosis of syphilitic uveitis was based on the following criteria: (1) reactive TR test and reactive NT test or second reactive TR test and no other cause for uveitis; (2) non-ocular manifestations of syphilis; or (3) remote history of syphilis with reactive NT test and inadequate treatment.
Results :
Among 442 patients with uveitis, 310 had at least one test for syphilis. NT tests (RPR, VDRL) and TR tests (FTA-Abs, TP-PA) were performed on 90 and 272 patients, respectively. Both tests were performed on 52 patients (50 results known). Among 310 patients tested, 14 (4.5%) were diagnosed with syphilitic uveitis (3.2% of all uveitis cases); all were tested with both NT and TR tests. Among those with both test results, 13 (26%) had both reactive NT and TR tests (12 with syphilitic uveitis and 1 with unrelated uveitis and persistently reactive RPR tests at low-titer after adequate treatment for neurosyphilis) and 4 (8.0%) had non-reactive NT tests and reactive TR tests (2 with syphilitic uveitis and 2 with unrelated uveitis and histories of adequately treated syphilis). For NT tests, PPV was 92.3% (12/13) and NPV was 97.4% (75/77). For TR tests, PPV was 82.4% (14/17) and NPV was 100% (253/253).
Conclusions :
The prevalence of syphilis among patients with uveitis is low, even in a tertiary referral center. Although patients with non-specific uveitis are generally a low-risk population, routine diagnostic testing of all patients to rule-out syphilis is appropriate given the consequences of untreated disease. Our results support reverse-sequence testing (TR test used initially), as NT tests can be non-reactive in late, active disease. Discordant results (non-reactive NT test, reactive TR test) may also reflect remote, adequately treated disease; thus, follow-up with an NT test, and possibly an alternate TR test, must be performed to confirm active disease.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.