Background: Syphilis is a sexually transmittable infectious disease caused by the spirochaete Treponema pallidum, which classically causes symptoms in three stages.
Case presentation: A previously healthy male in his thirties was admitted to our department after suffering from diplopia and unilateral ptosis for two days. Clinical examination revealed a left-sided oculomotor palsy with an ipsilateral ptosis. Supplementary cerebral computer tomography with angiography and magnetic resonance imaging was normal except for lymphadenopathy in the neck and mediastinum. As the patient was homosexual, we chose to test for HIV. The doctor on duty, being from Belarus where syphilis was recognised as endemic during her studies, also screened for syphilis. The HIV test was negative, while the syphilis test was positive. Lumbar puncture showed moderate pleocytosis and positive serology for syphilis, confirming the diagnosis of neurosyphilis. The patient recovered fully after a course of penicillin.
Interpretation: Even though syphilis remains uncommon in Norway, the incidence has been increasing in recent decades, especially in male homosexual communities. Patients may subsequently present with a diversity of symptoms.