[Diagnosis and biological monitoring of 6 neurosyphilis cases: value of cerebrospinal fluid analysis].

Our objective is to assess the relevance of the different laboratory findings in cerebrospinal fluid (CSF) and serum for the diagnosis and survey of active neurosyphilis. A retrospective study of six hospitalized neurosyphilitic patients at Neurological Hospital of Lyon from 1987 to 2002 was carried out. Six males were found, aged from 29 to 72 years. Neurosyphilis can be group in two categories: early (meningeal and meningovascular neurosyphilis) and late (progressive general paralysis and tabes dorsalis). All were tertiary stage and HIV negative. We performed in CSF, white and red cell count, cytology, total protein, glucose levels, in CSF and serum, albumin, total IgG, IgA, IgM for calculation of albumin quotient and IgG, IgA and IgM index. Serological tests for syphilis in CSF and serum are VDRL and TPHA. To increase the reliability of treponema antibody tests, the ratio of serum-to-CSF content of albumin is used to assess intrathecal production of treponema antibodies, especially the treponema pallidum hemagglutination assay (TPHA index). The CSF changes in neurosyphilis included elevated cell count with lymphocytic-plasmocytic cell reaction, increased protein content, strongly positive IgG index, numerous positive IgG oligoclonal bands, positive blood and CSF serology. Serological tests are difficult to interpret. Examination of CSF played a major role in the diagnosis and treatment of all forms of neurosyphilis. The CSF abnormalities improved with clinical improvement, especially in meningeal and vascular neurosyphilis, but the response in paresis and tabes was slower or nonexistent. Pleocytosis and protein are indicators of inflammatory activity in the central nervous system and are used as a clinical guide in the diagnostic, for treatment and re-treatment.