25 year old labourer 3 yrs back presented with penile ulcer not treated. Later he presented with neurological symptoms for which he got treated. Test to monitor response to treatment is

VDRL The history of the patient suggests neurosyphilis. Diagnosis of Neurosyphilis No definitive tool /test exists to establish the diagnosis of neurosyphilis with 100% accuracy. Most of the serological tests used in the diagnosis of syphilis cannot accurately diagnosis neurosyphilis. Hence, the diagnosis of neurosyphilis usually depends on combination of clinical features plus C.S.F. finding and serological tests. C.S.F. findings in syphilis:? - Lymphocytic pleocytosis - Protein is moderately elevated - Glucose is usually normal Among the serological tests - "The VDRL C.S.F. test is the standard serological test for and is considered diagnostic of neurosyphilis". - Since invasion of C.S.F. by syphilis stimulates production of antilipoidal antibodies in C.S.F., VDRL test can be performed on C.S.F. to diagnose neurosyphilis. - The VDRL test is highly specific albeit insensitive for the diagnosis of neurosyphilis. - The sensitivity of VDRL for neurosyphilis is 30% and specificity is 90%. Specific treponemol tests have proved to be quite inaccurate in the diagnosis of neurosyphilis Why ??? - The antibodies against the specific treponemal antigen have the tendency to cross C.S.F., so enough antibodies may be present in the C.S.F. even before neurosyphilis develops. - Therefore specific treponemal tests have no specificity for neurosyphilis. The C.S.F. becomes positive for these tests even when neurosyphilis is not present. Moreover, Specific treponemal tests cannot be used to monitor treatment because? - These tests become positive soon after infection and typically remain positive .for life despite adequate treatment. An impoant point - Like VDRL test RPR test can also be used to monitor the treatment in syphilis but it is not suitable for testing C.S.F., so it cannot be used in neurosyphilis. (Anantnarayan 8"/e p.375)