Manifestations due to neurosyphilis present as one of 3 categories: stroke due to arteritis, masses in the brain (granulomata), and chronic meningitis.
Although serum VDRL/TPPA tests will be positive in almost all patients, it’s important to remember that the diagnosis requires the presence of ALL of the following criteria:
1. positive treponemal (e.g. FTA-ABS, TP-PA) AND nontreponemal (e.g. VDRL, RPR) serum test results
2. positive CSF VDRL OR positive CSF FTA-ABS test result
3. one CSF laboratory test abnormality, such as pleocytosis (cell count >20/μL) or high protein level (>0.5 g/L)
4. clinical symptoms
This is important because the treatment of neurosyphilis is distinctly different from other forms, as it requires admission for IV antibiotics for at least 10 days.
Bonus Pearl: CSF RPR is unreliable as it is more likely to be falsely positive than other specific CSF testing.
References
Halperin JJ. Neuroborreliosis and Neurosyphilis. CONTINUUM 2018;24(5):1439–1458
