Parkinsonism plus syndrome in neurosyphilis: Clinical insights and brain imaging.

Background: While Parkinsonism plus syndrome (PPS) is one of several atypical manifestations in neurosyphilis patients, its clinical features and brain-related manifestations are inadequately documented. In this cross-sectional study, we endeavored to indicate some key clinical and imaging features of neurosyphilis patients, particularly those specific to PPS.

Methods: We retrospectively included all syphilis patients enrolled in the study from January 2021 to February 2024. All in all, 54 neurosyphilis patients with PPS were recruited. Their socio-demographical features, clinical status, presentations, laboratory manifestations and neuroimaging were analyzed retrospectively.

Results: The predominant phenotype was general paresis (GP). Median age at onset was 50 years, and 87.0 % of the patients were male. Bradykinesia (53.7 %) was the most common manifestation of PPS in neurosyphilis patients. The most frequent physical sign was orofacial dyskinesia (the Candy sign), which accounted for 51.9 % of cases. In nearly three quarters (71.1 %), magnetic resonance imagery revealed temporal, hippocampal lobe, or whole brain atrophy, while 13.3 % exhibited basal ganglia lacunar infarction, and 22.2 % cases had focal demyelination in the cerebral peduncle, cerebellum, frontal lobe, parietal lobe, hippocampus and/or lateral vertical.

Conclusions: Neurosyphilis patients exhibited PPS in involving bradykinesia, tremor rigidity and, in most cases, GP. Brain atrophy and basal ganglia lesion were the most common imaging findings in neurosyphilis patients with PPS. Our results should help to elucidate PPS characteristics PPS and neuroimaging mechanisms in neurosyphilis patients with PPS.