2020 Nov 23. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–.
Tabes dorsalis is a slowly progressive parenchymatous degenerative disease of the dorsal column and dorsal root of the spinal cord as a result of syphilis caused by infection with Treponema pallidum pallidum, one of three subspecies of Treponema pallidum that can cause sexually transmitted disease in humans. It generally occurs in the late tertiary stage of syphilis, but early involvement is reported. It may be accompanied by meningitis or meningomyelitis. Although CSF invasion often occurs early in syphilis, the clinical syndrome of tabes dorsalis, one of two manifestations of late neurosyphilis, usually occurs years, often two to three decades later. The pathogenesis of tabes dorsalis follows the pattern of syphilis elsewhere: a perivascular inflammatory response against the treponeme along with gummas (caseous necrosis in granulomata). Some studies support the invasion of the large myelinated nerve fibers by Treponema pallidum and subsequent neuronal degeneration. The cellular infiltration in the spinal cord displays T-helper cells, macrophages that produce cytokines that intensify the inflammatory process. Men who have sex with men and patients with HIV infection, or PLWH (patients living with HIV), are at a higher risk of neurosyphilis, especially the early types. HIV coinfection commonly occurs with neurosyphilis in the U.S. Thus, the clinical suspicion of neurosyphilis in PLWH must always remain strong with neurological, visual, or otologic signs or symptoms. Neurosyphilis can be both symptomatic and asymptomatic; in asymptomatic neurosyphilis, which is inflammation without symptoms, a lumbar puncture for CSF evaluation is controversial, but many feel it is important, especially in PLWH, to establish the diagnosis when present since treatment with penicillin at higher and longer doses than used for primary and secondary syphilis can retard or prevent the development of clinically evident and debilitating neurosyphilis, which, when it develops as late neurosyphilis is not as amenable to symptom reversal.