Syphilis CSF analysis


 * Clinical signs of neurosyphilis (i.e., cranial nerve dysfunction, meningitis, stroke, acute or chronic altered mental status, loss of vibration sense, and auditory or ophthalmic abnormalities) warrant further investigation and treatment for neurosyphilis.


 * Laboratory testing is helpful in supporting the diagnosis of neurosyphilis; however, no single test can be used to diagnose neurosyphilis in all instances.


 * Cerebrospinal fluid (CSF) abnormalities are common in persons with early syphilis.


 * Diagnosed by finding high numbers of leukocytes in the CSF or abnormally high protein concentration in the setting of syphilis infection.


 * VDRL in cerebrospinal fluid (CSF-VDRL), which is highly specific but insensitive, is the standard serologic test for CSF. Although some advocate using the FTA-ABS test to improve sensitivity.


 * When reactive in the absence of substantial contamination of CSF with blood, it is considered diagnostic of neurosyphilis; however in early syphilis, it can be of unknown prognostic significance.


 * Most other tests are both insensitive and nonspecific and must be interpreted in relation to other test results and the clinical assessment. Therefore, the laboratory diagnosis of neurosyphilis usually depends on various combinations of reactive serologic test results, CSF cell count or protein, and a reactive CSF-VDRL with or without clinical manifestations.

HIV Co-infection

 * There is anecdotal evidence that the incidence of neurosyphilis is higher in HIV patients, and some have recommended that all HIV-positive patients with syphilis should have a lumbar puncture to look for asymptomatic neurosyphilis.


 * Among persons with HIV infection, the CSF leukocyte count usually is elevated (>5 white blood cell count [WBC]/mm3); using a higher cutoff (>20 WBC/ mm3) might improve the specificity of neurosyphilis diagnosis.


 * The CSF-VDRL might be non-reactive even when neurosyphilis is present.


 * Therefore, additional evaluation using FTA-ABS testing on CSF can be considered. The CSF FTA-ABS test is less specific for neurosyphilis than the CSF-VDRL but is highly sensitive; neurosyphilis is highly unlikely with a negative CSF FTA-ABS test.

Resources

 * Sexually transmitted diseases treatment guidelines, 2010


 * Association of Public Health Laboratories (APHL). Laboratory Diagnostic Testing for Treponema pallidum. Expert Consultation Meeting Summary Report, January 13--15, 2009, Atlanta, GA


 * CDC: Guidelines for the laboratory diagnosis of gonorrhea, chlamydia and syphilis