To investigate the clinical characteristics and results of laboratory indexes detection of neurosyphilis with anti-HIV negative, and to improve the diagnosis and treatment level of neurosyphilis.

The clinical symptoms and laboratory characteristic (including imaging of MRI, CT) of 20 cases of neurosyphilis with anti-HIV negative were analyzed, retrospectively, in Xuanwu Hospital of Capital Medical University from January 2014 to October 2015. All the data were analyzed by SPSS 20.0 software.

There were 4 females and 16 males with adult neurosyphilis of anti-HIV-negative, with the average age of (52.6±12.4) years old (29-78 years old). There were 1 case (5%) with syphilitic meningitis, 8 cases (40%) with menigeal vascular type syphilis, 8 cases (40%) with paralytic dementia, 2 cases (10%) with tabes dorsalis, and 1 case (5%) with paralytic dementia and tabes dorsalis. There were 6 cases (30%) with clear history of syphilis and the misdiagnosed rate was 70%. Serum treponema pallidum particle assay (TPPA) and rapid plasma regain (RPR) were positive in 20 cases (1:2-1:128). The CSF-TPPA were positive in all patients, while 17 cases (85%) with CSF-RPR positive were as 1:2-1:16. The concentration of white blood cell (WBC) in CSF were abnormal (> 10 × 10⁶/L) in 18 cases (90%). The CSF-protein increased in 17 cases (85%) and CSF-glucose were abnormal in 15 cases (75%). The positive rates of CSF-IgG, oligoclonal band (OB) and 24 h-CSF IgG were 94.12% (15/17), 86.67% (13/15) and 92.31% (12/13), respectively. The results of CSF detected in different clinical types were not significant (χ²= 1.63, P = 0.95).

The clinical manifestations of neurosyphilis were complicated and easily misdiagnosed, and mainly occurs among young males. The detailed history, serum and cerebrospinal fluid examination could guide early diagnosis and treatment, and get better prognosis for suspected cases.