Syphilis with vision loss.

Background: Neurosyphilis is a rare cause of vision loss that can mimic the presentation of other diseases, including giant cell arteritis.

Case Presentation: A man in his sixties presented to the university hospital with a four-day history of right eye vision loss. He experienced a headache, myalgia and fatigue. Right eye vision was limited to finger counting at 2 metres and a relative afferent pupillary defect was present. He was tender over the right temporal area and had a decreased pulse in the right temporal artery. A pink maculopapular rash was present on the trunk. Laboratory testing showed elevated inflammatory parameters with ESR 50. Ischaemic optic neuropathy caused by giant cell arteritis was suspected, and treatment with high dose steroids was initiated. Expanded history revealed travel to Thailand five months prior to presentation and unprotected sex with multiple female partners. A non-painful sore had developed on his penis that resolved after 14 days.

Interpretation: Neurosyphilis was suspected and the diagnosis was subsequently confirmed. The patient received appropriate antibiotic therapy, and four months later his vision had almost normalised.