Neurosyphilis in AIDS patients: initial CSF VDRL may be negative

We report 2 HIV-seropositive patients with neurosyphilis whose initial CSF VDRL tests were negative. The CSF VDRL became positive after 12 days of IV penicillin treatment for syphilitic meningitis in the 1st patient. The 2nd patient developed syphilitic polyradiculopathy and a positive CSF VDRL 3 months after treatment with IV penicillin. Serial CSF VDRL determinations may be required in AIDS patients when a diagnosis of neurosyphilis is suspected.