Clinical features of syphilitic myelitis with longitudinally extensive myelopathy on spinal magnetic resonance imaging

BACKGROUND Syphilitic myelitis caused by Treponema pallidum is an extremely rare disease. However, symptomatic neurosyphilis, especially syphilitic myelitis, and its clinical features have been infrequently reported. Only a few cases of syphilitic myelitis have been documented. To the best of our knowledge, there are only 19 reported cases of syphilitic myelitis. However, the clinical features of syphilitic myelitis with longitudinally extensive myelopathy have been still not clear. AIM To explore the clinical features of syphilitic myelitis with longitudinally extensive myelopathy on spinal magnetic resonance imaging (MRI). METHODS First, we report a patient who suffered from syphilitic myelitis with symptoms of sensory disturbance, with longitudinally extensive myelopathy with "flip-flop sign" on spinal MRI. Second, we performed a literature search to identify other reports (reviews, case reports, or case series) from January 1987 to December 2018, using the PubMed and Web of Science databases with the terms including "syphilis", "neurosyphilis", "syphilitic myelitis", "meningomyelitis", "central nervous system", and "spine". We also summarized the clinical features of syphilitic myelitis with longitudinally extensive myelopathy. RESULTS A total of 16 articles of 20 cases were identified. Sixteen patients presented with the onset of sensory disturbance (80%), 15 with paraparesis (75%), and 9 with urinary retention (45%). Eleven patients had a high risk behavior (55%). Five patients had concomitant human immunodeficiency virus infection (25%). Serological data showed that 15 patients had positive venereal disease research laboratory test (VDRL)/treponema pallidum particle agglutination (TPHA), and 17 had positive VDRL/TPHA in cerebrospinal fluid (CSF). Seventeen patients were found to have elevated leukocytosis and protein in CSF. On MRI, 16 patients showed abnormal hyperintensities involved the thoracic spine, 6 involved the cervical spine, and 3 involved both the cervical and thoracic spine. There were 3 patients with the "flip-flop sign". All the patients were treated with penicillin, and 15 patients had a good prognosis. CONCLUSION Our case further raises awareness of syphilitic myelitis as an important complication of neurosyphilis due to homosexuality, especially in developing countries such as China.