What tests are used to isolate Treponema pallidum (T pallidum) from cerebrospinal fluid (CSF) in syphilitic meningitis?

Updated: Jul 16, 2019
  • Author: Rodrigo Hasbun, MD, MPH; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

In syphilitic meningitis, isolating T pallidum from the CSF is extremely difficult and time-consuming. The spirochete could be demonstrated by using dark-field or phase-contrast microscopy on specimens collected from skin lesions (eg, chancres and other syphilitic lesions).

The diagnosis is usually supported by the CSF VDRL test, which has a sensitivity of 30-70% (a negative result on the CSF VDRL test does not rule out syphilitic meningitis) and a high specificity (a positive test result suggests the disease). Care must always be taken not to contaminate the CSF with blood during spinal fluid collection (eg, traumatic tap).


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