Rapid seroconversion to Treponema pallidum and HIV positivity in a patient with retinal vasculitis

A patient with idiopathic retinal vasculitis was found to have rapid conversion of serological tests for Treponema pallidum and HIV. The diagnosis was confirmed by Venereal Disease Research Laboratory (VDRL) testing and dark ground illumination for T. pallidum, and enzyme-linked immunosorbent assay (ELISA) and Western blot assay tests for HIV. Following treatment with intravenous penicillin, the fundus lesions resolved and visual acuity recovered from inaccurate light projection to 6/24 in the right eye and from counting fingers close to face to 2/60 in the left eye. Serological tests for T. pallidum in patients with concurrent HIV infection may be unpredictable. Hence, it is important to repeat these tests even in the early treatment phase of patients with retinal vasculitis who have shown initial seronegativity. This enables earlier diagnosis and initiation of specific treatment.