Tabes dorsalis is a late manifestation of neurosyphilis that affects the posterior columns of the spinal cord and the dorsal roots. The disease process results in demyelination and inflammation with fibrosis of the spinal cord. Affected individuals most commonly present with sensory ataxia and stabbing, knife-like lancinating pain.
The onset of symptoms attributed to tabes dorsalis may occur anywhere from 3 to 20 years following syphilis infection . The most common presentation consists of loss of coordination (sensory ataxia) and sudden sharp, stabbing-like (lancinating) pain in the face, back, or lower extremities. Other symptoms include loss of pain and vibration sensations (paresthesia), seizures (status epilepticus), visceral crisis characterized by repeated attacks of severe epigastric pain, nausea, and vomiting, loss of sexual function, and bladder dysfunction (i.e., urinary retention and overflow incontinence)     .
Depending on the duration or stage of tabes dorsalis, a patient may present with either preataxia, ataxia, or paralysis . Patients with tabes dorsalis typically present with a slapping and/or wide-based gait during ambulation .
Workup consists of a thorough history, physical exam, and laboratory testing (serum and cerebrospinal spinal fluid analysis). The medical history should elicit information about the current or past diagnosis of syphilis, neurologic or ocular disease, and human immunodeficiency virus infection.
A neurological and ocular physical exam should be performed. Abnormalities of the pupils are common in patients with tabes dorsalis; Argyll-Robertson pupils are present in approximately half of patients . Other neurologic exam findings include loss of reflexes, proprioceptive sense, sensory ataxia, and/or Charcot joints . Examination of the skin may reveal trophic ulcers (mal perforans).
Serum testing will establish the diagnosis of syphilis. Commonly used tests for syphilis include:
During early syphilis, both types of test are positive. However, during late syphilis, such as with tabes dorsalis, non-treponemal tests may be negative and treponemal tests will be positive. This testing pattern indicates that the patient had syphilis in the past and may be at risk for neurosyphilis  .
A cerebrospinal fluid (CSF) exam should be performed to establish the diagnosis of neurosyphilis. Neurosyphilis is consistent with the following CSF findings: a negative CSF-VDRL, CSF lymphocyte count >5 cells/µL, and elevated protein count (>45 mg/dL) . The CSF-VDRL test may be false positive when there is contamination of the CSF with blood  . A polymerase chain reaction (PCR) for detection of treponemal nucleic acids may also be performed. The CSF may be tested for diagnostic markers of neurosyphilis such as intrathecally produced anti-treponemal antibodies and oligoclonal bands.
Tests that aid in the diagnosis, but are not confirmatory, include computed tomography (CT) and magnetic resonance imaging (MRI) of the brain and spine showing patterns of parenchymal disease that is consistent with neurosyphilis such as ischemic lesions, frontocortical atrophy, cerebral gumma, or disseminated frontal high signal lesions in T2-weighted MRI sequences  . Electrophysiologic testing may prove useful for ruling out neurological disorders; a triad of normal nerve conduction studies that reveal absent H-reflexes, normal nerve studies, and reduced posterior column conduction is highly indicative of tabes dorsalis. An electroencephalogram (EEG) findings may indicate complex partial or isolated status epilepticus  .