SEATTLE (FRONTLINE MEDICAL NEWS) – Neurologic symptoms are an unreliable indicator of neurosyphilis in patients with HIV, according to University of Washington, Seattle, investigators.

After tapping 385 HIV patients with untreated syphilis and possible central nervous system involvement, “the bottom line was that [symptom] sensitivity was so low that not having [symptoms] really shouldn’t reassure you. If you are concerned that your patient could have neurosyphilis because of other factors” – such as an especially high rapid plasma reagin titer or low CD4 count – “you still need to tap them,” said lead investigator Arielle P. Davis, MD , who is in the department of neurology at the university.

It’s an important finding because the Centers for Disease Control and Prevention currently recommends lumbar punctures when patients have neurologic symptoms, and some people wait for them before tapping. The University of Washington team found that there can be neurologic involvement even without symptoms.

In the prospective study , symptoms were simply not sensitive enough to rule anything out. Moderate or greater photophobia had a sensitivity of 6.3% for a reactive cerebrospinal fluid Venereal Disease Research Laboratory (CSF-VDRL) syphilis test; moderate or greater vision loss was 38.1% sensitive for reactive CSF-VDRL, moderate or greater hearing loss was 13.2% sensitive, and moderate or greater gait incoordination was 1.5% sensitive.

Specificity was markedly better for each of those symptoms, and more than 95% for moderate or greater photophobia, hearing loss, and gait incoordination. “In general, as the severity of photophobia, vision loss, hearing loss, and gait incoordination increased, the specificity increased, but at the expense of sensitivity,” the investigators wrote in their poster, which Dr. Davis presented at the Conference on Retroviruses & Opportunistic Infections in partnership with the International Antiviral Society.

CSF-VDRL was reactive in 68 subjects (18%). The odds of a reactive CSF-VDRL were significantly higher in patients with vision loss (odds ratio, 2.2; 95% confidence interval, 1.2-4.0; P = .01) and trended toward significance in those with moderate or greater hearing loss (OR, 2.5; 95% CI, 1.0-6.6; P = .06).

Overall, “patients with mild or greater photophobia, vision loss, gait incoordination, and moderate or greater hearing loss were significantly more likely to have a reactive CSF-VDRL, and the presence of any of these four symptoms should [remain] a criterion for pursuing a lumbar puncture.” However, “lack of neurologic symptoms in HIV-infected patients with syphilis should not reassure clinicians that their patients do not have neurosyphilis,” Dr. Davis and her team concluded.

The participants were almost entirely men and mostly white. The average age was about 40 years, and the median rapid plasma reagin titer was 1:64. About 48% of the subjects reported at least mild vision loss, 40% reported mild or worse headache, and 17% reported some degree of hearing loss. Overall, 15.5%-17.2% reported at least mild photophobia, stiff neck, or gait incoordination.

The work was funded by the National Institutes of Health. Dr. Davis did not have any relevant disclosures.