Abstract
Idiopathic intracranial hypertension (IIH) is being diagnosed more often in the UK due to the rise in obesity. In fact, patients who present with bilateral optic disc swelling are habitually put on the papilloedema pathway, often without consideration of other diagnoses. We report the case of a middle-aged woman diagnosed with papilloedema and managed as IIH, until, cerebrospinal fluid (CSF) analysis revealed evidence of lymphocytic meningitis secondary to syphilis. The patient was treated successfully with intravenous antibiotics. Syphilis is the great masquerader and should be a diagnosis to consider in patients who have CSF findings incongruent with their clinical presentation.