Presumptive Syphilitic Polyarthritis Mimicking Seronegative Rheumatoid Arthritis in a Resource-Limited Setting: A Case Report and a Lesson for General Practitioners in Remote Areas

Abstract

Background: Syphilis is a multi-systemic sexually transmitted infection capable of mimicking numerous diseases, including rheumatoid arthritis. Musculoskeletal involvement in secondary syphilis is rare and may be easily overlooked, especially where diagnostic capacities are limited. This report highlights atypical clinical features, diagnostic constraints, and therapeutic response in a patient facing diagnostic and treatment affordability barriers.

Case Presentation: A 29-year-old woman presented with progressive symmetric polyarthritis without any syphilitic stigmata. Initial investigations suggested seronegative rheumatoid arthritis; however, a reactive Venereal Disease Research Laboratory (VDRL) test prompted a presumptive diagnosis of syphilitic polyarthritis despite absence of confirmatory treponemal tests due to unavailability and unaffordability. Treatment with weekly benzathine penicillin G for three weeks resulted in complete symptom resolution and VDRL seronegativity on follow-up at three and six months.

Conclusion: In resource-poor settings, high clinical suspicion for syphilis is critical in unexplained polyarthritis when confirmatory diagnostics are inaccessible. Early presumptive diagnosis using VDRL testing and adequate prompt treatment prevents unnecessary complications and public health risks, including congenital syphilis.