Neurosyphilis.

No portion of the central nervous system is immune to the ravages of syphilis. Infection by Treponema pallidum can affect the meninges, brain, brainstem, spinal cord, nerve roots, and cerebral and spinal blood vessels. As a consequence, the disease may present in diverse and, at times, diagnostically challenging fashions. Neurologic manifestations of syphilis may develop within months of the initial infection or, alternatively, take decades to appear. Although approximately one-third of individuals infected by T. pallidum display cerebrospinal fluid abnormalities suggestive of invasion of the central nervous system by the organism, only a fraction of these develop clinically significant neurologic manifestations. The features of neurosyphilis may be modified by the concomitant presence of immunosuppressive agents or conditions such as HIV/AIDS. The epidemiology of neurosyphilis has largely paralleled that of syphilis in general. A dramatic decline occurred by the early 1950s as a consequence of public health measures and the widespread use of antibiotics. The incidence had increased by the onset of the AIDS pandemic and has since corresponded with the adoption of safe sex practices. The CSF Venereal Disease Research Laboratory (VDRL) test remains the "gold standard" for diagnosis, but is not invariably positive. Penicillin remains the most effective and recommended therapy.