Neurosyphilis: Knowledge Gaps and Controversies.

After reaching a nadir at the turn of the century, syphilis rates in the United States have increased since 2000. Treponema pallidum may disseminate to the central nervous system within hours to days after inoculation. In this review, we focus on knowledge gaps and areas of controversy in neurosyphilis epidemiology, diagnosis, and management. Modern estimates of the prevalence of neurosyphilis are hindered by the lack of consistent reporting data and are based on relatively small retrospective cohort studies. The various diagnostic modalities for neurosyphilis have significant limitations. Although several novel biomarkers for neurosyphilis have been evaluated, none to date have found a place in clinical practice. The role of a cerebrospinal fluid examination in patients without neurological symptoms continues to be an area of controversy, whereas the data for the use of antibiotic regimens other than intravenous aqueous or intramuscular procaine penicillin for the treatment of neurosyphilis are limited. As syphilis incidence continues to increase unabated in many countries around the world, it is critical to address these gaps of knowledge.