The Great Imitator: Ocular Syphilis Presenting as Posterior Uveitis

Objective: Rare disease Background: Syphilis is often known as the "Great Imitator". The differential diagnosis of posterior uveitis is broad with ocular syphilis being particularly challenging to diagnose as it presents similarly to other ocular conditions such as acute retinal necrosis. Case Report: A 34-year-old woman with multiple sexual partners over the past few years presented with painful and progressively worsening unilateral vision loss for 2 weeks. Several months prior, she had reported non-specific symptoms of headache and diffuse skin rash. Despite treatment with oral acyclovir for 3 weeks, her vision progressively declined, and she was referred to the university ophthalmology clinic for further evaluation. On examination, there was concern for acute retinal necrosis and she was empirically treated with parenteral acyclovir while awaiting further infectious disease study results. Workup ultimately revealed ocular syphilis, and neurosyphilis was additionally confirmed with cerebrospinal fluid studies. Treatment with intravenous penicillin was promptly initiated with complete visual recovery. Conclusions: Ocular syphilis varies widely in presentation and should be considered in all patients with posterior uveitis, especially with a history of headache and skin rashes. However, given that acute retinal necrosis is a more common cause of posterior uveitis and can rapidly result in permanent vision loss, it should be empirically treated whenever it is suspected while simultaneous workup is conducted to evaluate for alternative diagnoses.