Neurosyphilis Diagnosis and Treatment
Clinical Scenarios Requiring CSF Examination
- Neurosyphilis should be considered in any patient with clinical evidence of neurologic involvement with syphilis, including cognitive dysfunction, motor or sensory deficits, ophthalmic or auditory symptoms, cranial nerve palsies, and signs or symptoms of meningitis, as recommended by the Centers for Disease Control and Prevention 1, 2
- A cerebrospinal fluid (CSF) examination should be performed in patients with neurologic signs or symptoms, such as cognitive dysfunction, motor/sensory deficits, or meningitis symptoms, according to the Centers for Disease Control and Prevention 1, 3
- Ophthalmic manifestations, such as uveitis, neuroretinitis, or optic neuritis, require a CSF examination, as suggested by the Centers for Disease Control and Prevention 1, 2
- Auditory symptoms, including hearing loss or tinnitus, necessitate a CSF examination, as recommended by the Centers for Disease Control and Prevention 1, 4
- Cranial nerve palsies require a CSF examination, according to the Centers for Disease Control and Prevention 1, 3
- Evidence of tertiary syphilis, such as aortitis, gumma, or iritis, necessitates a CSF examination, as suggested by the Centers for Disease Control and Prevention 5, 6
- Treatment failure of prior syphilis therapy requires a CSF examination, as recommended by the Centers for Disease Control and Prevention 5, 6
- HIV infection necessitates a CSF examination, according to the Centers for Disease Control and Prevention 5, 6
- Serum nontreponemal titer ≥1:32 requires a CSF examination, unless the duration of infection is known to be <1 year, as suggested by the Centers for Disease Control and Prevention 5, 6
- Non-penicillin therapy planned requires a CSF examination, unless the duration of infection is known to be <1 year, as recommended by the Centers for Disease Control and Prevention 5, 6
Special Considerations for HIV-Infected Patients
- In HIV-infected patients, neurosyphilis should be considered in the differential diagnosis of neurologic disease, even with atypical presentations, as recommended by the Centers for Disease Control and Prevention 7, 8
- CSF abnormalities consistent with neurosyphilis are more likely in HIV-infected persons with CD4 count ≤350 cells/mL and/or RPR titer ≥1:32, according to the Centers for Disease Control and Prevention 8
- HIV-infected patients with early syphilis may be at increased risk for neurologic complications, as suggested by the Centers for Disease Control and Prevention 8
- Unusual serologic responses may occur in HIV-infected patients, including higher than expected titers, false-negative results, or delayed seroreactivity, as recommended by the Centers for Disease Control and Prevention 1, 7
Diagnostic Approach
- When neurosyphilis is suspected, both treponemal and non-treponemal serologic tests should be performed, as recommended by the Centers for Disease Control and Prevention 1
- CSF examination is essential, looking for pleocytosis, elevated protein, and positive CSF-VDRL, according to the Centers for Disease Control and Prevention 1, 2
- All patients with syphilis should be tested for HIV, as recommended by the Centers for Disease Control and Prevention 1, 2
Treatment Considerations
- Aqueous crystalline penicillin G 18-24 million units per day, administered as 3-4 million units IV every 4 hours or continuous infusion, for 10-14 days, is the recommended treatment for neurosyphilis, as suggested by the Centers for Disease Control and Prevention 1, 2
- For patients with penicillin allergy, ceftriaxone 2g daily either IM or IV for 10-14 days can be considered, though cross-reactivity is possible, according to the Centers for Disease Control and Prevention 2, 9
- Follow-up CSF examination should be performed every 6 months until the cell count normalizes, as recommended by the Centers for Disease Control and Prevention 1, 2
Common Pitfalls to Avoid
- Failing to consider neurosyphilis in patients with unexplained neurologic deficits, especially when presenting with encephalitis-like symptoms, is a common pitfall, as warned by the Centers for Disease Control and Prevention 1, 2
- Not performing CSF examination in patients with ocular syphilis, which is frequently associated with neurosyphilis, is a common pitfall, as warned by the Centers for Disease Control and Prevention 1, 2
- Inadequate follow-up after treatment, with CSF examination repeated every 6 months until cell count normalizes, is a common pitfall, as warned by the Centers for Disease Control and Prevention 1, 2
- Not testing for HIV in all patients with syphilis is a common pitfall, as warned by the Centers for Disease Control and Prevention 1, 2
CDC Recommendations for Evaluation and Management of Neurosyphilis
Indications for Lumbar Puncture (CSF Examination)
- Perform urgent lumbar puncture in patients with suspected neurosyphilis who exhibit neurologic signs or symptoms (e.g., cognitive dysfunction, motor or sensory deficits, cranial nerve palsies, meningeal signs). 10
- Perform urgent lumbar puncture in patients who have ophthalmic manifestations such as uveitis, neuroretinitis, or optic neuritis. 10
- Perform urgent lumbar puncture in patients with auditory symptoms (hearing loss or tinnitus). 10
- Perform urgent lumbar puncture when there is evidence of tertiary syphilis (e.g., aortitis, gumma, iritis). 10
- Perform urgent lumbar puncture after treatment failure of prior syphilis therapy. 10
- Perform urgent lumbar puncture in HIV‑infected patients who have late‑latent syphilis or syphilis of unknown duration. [10][11]
- Perform urgent lumbar puncture when the serum nontreponemal titer is ≥ 1:32 (unless infection duration is known to be < 1 year). 12
Serologic Testing
- All patients with syphilis must be tested for HIV as a mandatory component of the work‑up. 11
CSF Findings Supporting Neurosyphilis
- CSF pleocytosis is typically mild mononuclear, ranging from 10–200 cells/µL. 11
- CSF protein is usually normal or only mildly elevated. 11
- CSF‑VDRL is highly specific but not sensitive; a reactive result confirms neurosyphilis, while a non‑reactive result does not exclude it. 11
- The combination of CSF white‑blood‑cell count > 10 cells/µL plus a reactive CSF‑VDRL strongly supports a neurosyphilis diagnosis. 11
- In HIV‑infected patients, mild CSF pleocytosis of 5–15 cells/µL can occur, especially when CD4⁺ counts are > 500 cells/µL, complicating interpretation. 11
Treatment Considerations for HIV‑Infected Patients
- Use the standard neurosyphilis regimen (IV aqueous crystalline penicillin G) in HIV‑infected patients, but recognize they have a higher risk of neurologic complications and increased rates of treatment failure; therefore, closer clinical and CSF monitoring is required. 11