From the Guidelines
Tabes dorsalis is a late manifestation of neurosyphilis characterized by progressive degeneration of the posterior columns of the spinal cord and dorsal roots, with key features including lightning pains, sensory ataxia, Argyll Robertson pupils, loss of deep tendon reflexes, and Romberg's sign. The diagnosis of tabes dorsalis can be supported by imaging studies, such as MRI of the spine, which can evaluate the spinal column and soft tissues, including the spinal cord, and help identify atrophy of the cervical spinal cord or compressive myelopathy 1. Key features of tabes dorsalis include:
- Lightning pains (sudden, severe stabbing pains in the legs or trunk)
- Sensory ataxia (unsteady gait due to loss of position sense)
- Argyll Robertson pupils (small pupils that accommodate but don't react to light)
- Loss of deep tendon reflexes (particularly knee and ankle jerks)
- Romberg's sign (inability to maintain balance with eyes closed) These symptoms result from the spirochete Treponema pallidum damaging sensory neurons in the dorsal root ganglia and posterior columns, disrupting proprioception and vibration sense pathways. It is worth noting that other conditions, such as syphilis, can also cause bilateral fluctuating hearing loss, and tabes dorsalis, and multiorgan involvement 1. However, the primary concern in diagnosing and managing tabes dorsalis is to prevent permanent disability through early diagnosis and treatment with penicillin G.
From the Research
Clinical Features of Tabes Dorsalis
- Progressive ataxia, lightning pains, loss of proprioception, and urinary incontinence are characteristic features of tabes dorsalis 2
- The most frequent initial symptoms include limb numbness and lightning pains 2
- Physical signs such as positive Romberg's sign and Argyll Robertson pupil are commonly observed 2, 3
- Decreased deep tendon reflexes, reduced sense of vibration, and unsteady gait are also reported 3
- Sensory ataxia, neuropathic pain, paresthesia, and gastrointestinal disturbance are less common presentations 4
Diagnostic Challenges
- The absence of a definitive diagnostic standard and non-specific clinical manifestations lead to a significant rate of misdiagnoses 2
- Serological tests, such as rapid plasma regain (RPR) and Treponema pallidum particle agglutination (TPPA), are essential for diagnosis 2, 3
- CSF samples are often TPPA-reactive, and intramedullary hyperintensity on T2-weighted imaging of spinal MRI can be observed 2
- A thorough medical history and targeted diagnostic workup are crucial for early recognition and diagnosis of neurosyphilis 3
Treatment and Outcome
- Penicillin G is the mainstay therapy for neurosyphilis and can improve and resolve spinal cord lesions associated with tertiary syphilis 4
- Early treatment can prevent irreversible sequelae, but delayed diagnosis and treatment can result in unfavorable outcomes 3, 5
- Clinical improvement can be achieved with anti-syphilitic treatment, but some patients may experience symptom relapse or have an unfavorable outcome 2, 5