Neurosyphilis prevalence at a Portuguese stroke unit care

Syphilis is a systemic human disease which is caused by infection with the spirochete Treponema pallidum. It is spread worldwide, and there has recently been an increase in its incidence. Neurosyphilis (NS) can have a variety of presentations; meningovascular NS is a specific affection of the Treponema which occurs in an early stage after the primary infection, causing an inflammatory arteriopathy which may result in an ischemic stroke. As a rare manifestation of syphilis, there are few prevalence and epidemiological studies, and data are almost non-existent. The objective of this study is to analyse the prevalence of meningovascular NS in a stroke unit in a tertiary hospital.

A descriptive retrospective study was carried out over a period of 44 months in a stroke unit. All patients admitted had neurological symptoms compatible with a vascular event, and routine blood tests including infectious screening were performed. Those with positive test results for syphilis were identified and proceeded to lumbar puncture to CSF cytochemical analysis and VDRL. NS was categorized as confirmed or probable (using CDC criteria).

A total of 525 patients were admitted, and 62.53% were submitted to a routine screening for syphilis. A total of 309 patients (95.67%) revealed a negative screening; 12 patients (3.72%) had a positive syphilis serology. Among the 12 patients with positive screening, a single case of NS (0.31%) was identified.

We observed a low prevalence of NS (0.31%), but this result was surprisingly higher than what was expected in an elderly population.