A Rare Case of Syphilitic Charcot Arthropathy Involving the Foot in an Asian Patient: A Case Report and Review of Literature

Syphilis is an infection caused by <i>Treponema pallidum</i>. Without treatment, neurosyphilis may develop and lead to complications such as Charcot arthropathy (CA). First described by Jean-Martin Charcot, this condition was initially recognized as a manifestation of syphilitic infection. With the advent of antibiotics, the incidence of syphilis declined; however, it has since re-emerged in regions including Europe, North America, and China. In recent years, there has been a relative paucity of literature on syphilitic CA, with most reports involving the hip or knee. This article describes a rare presentation of syphilitic CA affecting the foot and aims to contribute to the limited body of literature while underscoring the importance of considering syphilis as a differential cause of CA of the foot in the modern era. A 37-year-old patient with a remote history of syphilis (diagnosed approximately 10-15 years earlier) presented with an atraumatic, progressively worsening swelling of the right foot over three months, associated with a progressive deformity of unknown duration. Imaging demonstrated features of CA involving the foot, with no radiological evidence of infection. A workup for potential etiologies was performed. Cerebrospinal fluid (CSF) analysis revealed a Venereal Disease Research Laboratory (VDRL) titer of 1:8 and a positive Line Immunoassay (LIA) syphilis CSF immunoglobulin G (IgG) test. The patient received intravenous benzylpenicillin therapy followed by deformity-correction surgeries. Four years after the initial operation, the patient was ambulating independently without assistive devices and had no wound complications. Syphilitic CA is a serious complication and should be considered in the differential diagnosis of patients presenting with features of neuropathic arthropathy, even in the modern era. This is particularly relevant for cases involving the foot, where diabetes is the most common aetiology and may lead clinicians to erroneously assume a diagnosis of diabetic CA. Early consideration and confirmation of syphilitic CA enables the timely initiation of antibiotic therapy for tertiary syphilis, while the CA can be managed through deformity-correction surgery if required.