Clinical features associated with neurosyphilis in people living with HIV and late latent syphilis

Background The diagnosis of neurosyphilis is a challenge, and the criteria for deciding when to perform a lumbar puncture are still controversial, especially in people living with HIV with a late latent syphilis diagnosis. Methods Retrospective analysis of demographic, clinical, and laboratory data of people with HIV and documented late latent syphilis or syphilis of unknown duration with a cerebrospinal fluid VDRL test. Results 122 patients were evaluated, of whom 52 had the diagnosis of neurosyphilis. Patients with and without neurosyphilis presented a similar viral load and lymphocyte CD4+ T-cell count. Neurological symptoms (OR 6.4, 95% CI 2.1–22.4; p < 0.01), serum VDRL titers of 1:32 (p<0.01), 1:64 (p = 0.055), and ≥1:128 (p < 0.001) were associated with neurosyphilis. Furthermore, serum VDRL ≥1:32 were associated with (OR 24.9, 95% CI 5.45–154.9; p < 0.001) or without (OR 6.5, 95% CI 2.0–29.2; p = 0.004) neurological symptoms with neurosyphilis; however, VDRL ≤1:16 with neurological symptoms can be associated with neurosyphilis (OR 7.6, 95% CI 1.03–64.3; p = 0.046). Conclusion Neurological symptoms, particularly headache, were predictors of neurosyphilis in people with HIV irrespective of their viral load and lymphocyte CD4+ T-cell count in late latent syphilis. A serum VDRL ≥1:32 increased the risk of neurosyphilis in patients with or without any symptoms.