Neurosyphilis

Neurosyphilis is caused by the bacterium Treponema pallidum subspecies pallidum (T. pallidum). The organism gains entry into the central nervous system (CNS) early (primary syphilis or chancre phase) in the course of infection. While most patients are able to mount an immune response that effectively clears CNS invasion without long-term complications, a minority go on to develop asymptomatic or symptomatic neurosyphilis. Neurosyphilis has been divided into early and late stages. The early stages include asymptomatic meningitis, symptomatic meningitis, gumma, and meningovascular syphilis, while the late stages include dementia paralytica and tabes dorsalis. Ocular and otologic syphilis can occur at any time but often accompany the acute meningitis of early neurosyphilis. The diagnosis of symptomatic neurosyphilis requires meeting clinical, serologic, and cerebrospinal fluid (CSF) criteria, while the diagnosis of asymptomatic neurosyphilis relies on serologic and CSF criteria alone. In the last several decades, a persistent rise in syphilitic meningitis and other forms of early neurosyphilis have been seen in the human immunodeficiency virus-positive population, principally in men who have sex with men. This article reviews the clinical presentation, diagnosis, and treatment of neurosyphilis, and it addresses the controversy regarding the role of lumbar puncture early in the course of infection.