The big imitator strikes again: a case report of neurosyphilis in a patient with newly diagnosed HIV.

In all patients with new-onset dementia or untreatable psychosis, neurosyphilis should always be considered. Argyll Robertson pupils are regarded as pathognomonic of neurosyphilis. The management of neurosyphilis includes high-dose IV benzyl penicillin for 10 to 14 days. Close follow-up including a lumbar puncture after 6 months is warranted to ensure treatment recovery.