Symptomatic neurosyphilis in immunocompetent patients is nowadays a rare diagnosis. Yet, if not properly diagnosed and treated, consequences for the patient's health are severe. Known as “the great imitator”, its detection involves both a high degree of suspicion and adequate diagnostic tests. Psychiatric symptoms are often the presenting symptoms of this illness.

The authors report four cases of neurosyphilis with psychiatric symptoms (general paresis) in immunocompetent patients. all four patients were initially referred for observation by a psychiatrist in the emergency room. Special diagnostic features of each case and potential diagnostic pitfalls are highlighted.

To raise awareness to the importance of this rare but highly disabling disease.

Review of clinical records and complementary exams.

All patients were male, two Caucasian and two African Black, with ages ranging from 41–56 years old. Clinical presentations were quite distinct, showing the symptomatic heterogeneity of paretic neurosyphilis. Blood VDRL test was negative in one case, CSF VDRL was negative in another case. TPHA was always positive in blood and CSF. White cell count and protein quantification in the CSF remains important to confirm diagnosis.

Current prevalence of symptomatic neurosyphilis in Western Europe is unknown. Atypical cases presenting with heterogeneous psychiatric and neurologic symptoms, with no previous history of mental illness, should undergo blood VDRL testing, and specific blood treponemal testing should be considered in specific situations. A high index of clinical suspicion is needed. Confirmation of diagnosis is only possible through further CSF analysis.