Asymptomatic neurosyphilis.
Lumbar puncture was performed in 18 patients with latent syphilis to rule out asymptomatic neurosyphilis. In seven patients the CSF findings were abnormal. The parameters used in CSF were cell count, total protein, immunoglobulins (IgG, IgA, IgM), IgG index, and serologic tests for syphilis (VDRL, Kolmer, RPCF and FTA-ABS, including monospecific IgG and IgM conjugates). In three patients, the CSF findings 7-10 months after treatment are also given. Penicillin levels in serum and CSF were determined in two patients after aqueous procaine penicillin G im with and without oral probenecid. The effect of blood contamination on the differentiation between normal and abnormal CSF may not be significant.