Diagnosis of neurosyphilis: a critical assessment of current methods

Clinical features of 74 patients with neurosyphilis and 38 syphilitic patients with nonsyphilitic neurologic disorders were correlated with results of their serum and cerebrospinal fluid (CSF) VDRL and FTA tests, and with the WBC count and total protein level in the CSF. The most common clinical features in those having neurosyphilis were reflex changes (53.9%), peripheral neuropathy (44.5%), ataxia (38%), and cranial nerve palsies (24.3%). In 27% of the patients with neurosyphilis the CSF was VDRL-reactive, while in 77% the CSF was FTA-reactive. The frequency of elevated WBC counts in various serologic categories ranged from 23% to 46%, and the frequency of elevated protein levels ranged from 23% to 27%; neither the mean WBC count nor the protein level differed significantly among the different serologic categories (P less than .05). Only two of the 74 patients with neurosyphilis had elevation of both the WBC and protein level. None of the syphilitic patients without neurosyphilis had an elevated WBC or protein level, though the CSF was FTA-reactive in all 38. Among the neurosyphilis patients whose CSF was VDRL-nonreactive but FTA-reactive, 21% had an elevated protein level and 26% had an elevated WBC count. These results support the view that patients having neurosyphilis will not necessarily have either VDRL-reactive CSF or the other expected CSF abnormalities.