In neurosyphilis, is a lumbar puncture performed before or after a Venereal Disease Research Laboratory (VDRL) test?

From the Guidelines

In neurosyphilis evaluation, a lumbar puncture is performed after a positive serum VDRL or RPR test. The diagnostic approach typically begins with serum treponemal and non-treponemal tests (like VDRL or RPR) 1. When these blood tests are positive and there are neurological symptoms suggesting neurosyphilis, a lumbar puncture is then performed to analyze cerebrospinal fluid (CSF). The CSF is tested for VDRL, protein levels, cell count, and sometimes CSF-FTA-ABS. This sequential approach is important because serum tests serve as initial screening, and CSF analysis confirms central nervous system involvement. A positive CSF-VDRL is highly specific for neurosyphilis, though sensitivity is limited (30-70%) 1.

Some key points to consider in the diagnosis of neurosyphilis include:

• The sensitivity of CSF VDRL ranges from 49-87.5% and the specificity ranges from 74-100% for diagnosing neurosyphilis 1
• The sensitivity of CSF RPR ranges from 51.5-81.8% and the specificity ranges from 81.8-100% 1
• A mixture of symptomatic and asymptomatic patients was included in many studies, and it was not always possible to determine nontreponemal test characteristics separately for these groups 1
• Clinical guidelines focus on obtaining lumbar punctures primarily in situations in which patients are symptomatic, as the significance of CSF abnormalities in the absence of symptoms is unclear 1

Treatment typically involves high-dose intravenous penicillin G (18-24 million units daily) for 10-14 days to ensure adequate penetration into the CSF. This sequential testing approach prevents unnecessary lumbar punctures while ensuring proper diagnosis of neurosyphilis in patients with systemic syphilis who have neurological manifestations. The most recent and highest quality study 1 supports this approach, and it is essential to follow this guideline to prioritize morbidity, mortality, and quality of life as the outcome.

From the Research

Lumbar Puncture and VDRL in Neurosyphilis

• The order of performing a lumbar puncture (LP) and Venereal Disease Research Laboratory (VDRL) test in neurosyphilis is not explicitly stated in the provided studies.
• However, the studies suggest that LP is a crucial diagnostic tool for neurosyphilis, and CSF-VDRL is used to confirm the diagnosis 2, 3, 4, 5, 6.
• The CSF-VDRL test is typically performed on the cerebrospinal fluid (CSF) sample obtained through LP, implying that LP is done before the CSF-VDRL test 2, 3.
• The studies emphasize the importance of clinical judgment and the use of multiple diagnostic criteria, including serologic tests, CSF analysis, and clinical presentation, to diagnose neurosyphilis 4, 5, 6.
• The sensitivity and specificity of CSF-VDRL in diagnosing neurosyphilis are discussed in the studies, with varying results 2, 3.

Diagnostic Criteria for Neurosyphilis

• The diagnosis of neurosyphilis requires a combination of clinical, serologic, and CSF criteria 5.
• The CSF-VDRL test is a key diagnostic tool, but its sensitivity and specificity can vary 2, 3.
• Other diagnostic tests, such as the Treponema pallidum particle agglutination assay (TPPA), may be used to support the diagnosis of neurosyphilis 4.

Clinical Presentation and Diagnosis

• Neurosyphilis can present with a range of clinical symptoms, including neurologic symptoms such as headache, stiff neck, photophobia, and vision or hearing loss 2, 5.
• The diagnosis of neurosyphilis can be challenging, and a high index of suspicion is essential to make an accurate diagnosis 4, 6.