OBJECTIVES To evaluate the usefulness of routine lumbar puncture in non-HIV patients with untreated latent syphilis.

METHODS We conducted a prospective study in Seoul National University Bundang Hospital from May 2003 to December 2005. Participants in routine health check-ups of the healthcare system were screened for serological evidence of syphilis by the Treponema pallidum particle agglutination (TPPA) test. Lumbar puncture was performed, with consent, on untreated latent syphilitic patients. Neurosyphilis was defined as positivity for cerebrospinal fluid Venereal Disease Research Laboratory (CSF VDRL) or pleocytosis with positivity for CSF TPPA or elevation of CSF protein with IgG index exceeding 0.85.

RESULTS Of 21 507 participants, 282 (1.4%) had serological evidence of syphilis. 117 (41%) of these had a history of syphilis treatment and 2 were seropositive for HIV. Among the 163 non-HIV patients with untreated latent syphilis, 70 (43%) underwent lumbar puncture. All the patients had VDRL titres less than 1:16. Abnormal neurological signs or symptoms were present in eight (11%) patients. CSF abnormalities were seen in 57 (81%), but no patient (0%, 95% CI 0 to 6.2) was diagnosed with neurosyphilis.

CONCLUSIONS The estimated prevalence of neurosyphilis among non-HIV patients with untreated latent syphilis and serum VDRL <1:16, was below 6.2%.