Prevalence of neurosyphilis in human immunodeficiency virus-infected patients with latent syphilis

Abstract

Purpose: A prospective study was done to determine the prevalence of confirmed neurosyphilis (cerebrospinal fluid [CSF] Venereal Disease Research Laboratory [VDRL]-reactive) in human immunodeficiency virus (HIV)-infected patients with latent syphilis (reactive serum rapid plasma reagin [RPR] and microhemagglutination-Treponema pallidum [MHA-TP]).

Patients and methods: All HIV-infected patients seen for their first visit at the Los Angeles County/University of Southern California Medical Center AIDS Clinic from June through December 1990 were screened for latent syphilis. Those with reactive serum RPRs and MHA-TPs who had not received recent (within 6 months) therapy for syphilis were offered diagnostic CSF sampling.

Results: A total of 312 patients were screened, of whom 71 (22.8%) had reactive serum RPRs and MHA-TPs. Thirty-three of these patients (47%) had diagnostic CSF sampling (26 refused lumbar puncture or were lost to follow-up; 12 had had recent therapy for syphilis and thus did not have CSF sampling). Among the 33 patients who had CSF sampling, 20 (60.6%) had normal CSF profiles (white blood cell count less than 8/mm3; protein less than 0.60 g/L; glucose greater than 2.8 mmol/L) and nonreactive CSF VDRLs. Ten of the 33 patients (30.3%) had abnormal CSF profiles and nonreactive CSF VDRLs, and three of 33 (9.1%) had reactive CSF VDRLs.

Conclusions: Asymptomatic neurosyphilis was found in 9.1% of our patient population undergoing CSF sampling, giving a 1.0% prevalence of CSF VDRL-reactive neurosyphilis in the population we screened. The abnormal CSF findings may have been due to either nonreactive CSF VDRL neurosyphilis, central nervous system infection with HIV, or infection with some unrecognized agent.