Cerebral neurosyphilis mimicking acute frontal lobe infarction: a case report

Introduction: Syphilis, caused by Treponema pallidum, the "great imitator," has re-emerged as a public health concern. It presents with diverse manifestations, ranging from asymptomatic meningitis and psychiatric changes to meningovascular syphilis presenting as ischemic stroke. We aim to report a case of an elderly male with cerebral neurosyphilis mimicking an acute frontal lobe infarction, emphasizing the importance of considering syphilis in patients with atypical risk factors or clinical presentations. Case presentation: A 77-year-old male presented with subacute personality changes and executive dysfunction. Neuroimaging demonstrated nonspecific right frontal lobe changes without definitive evidence of acute ischemia. Serologic testing revealed a positive serum Venereal Disease Research Laboratory (VDRL) titer of 1:256, and cerebrospinal fluid (CSF) analysis confirmed neurosyphilis. The patient was treated with intravenous benzylpenicillin with clinical and serologic improvement. Discussion: Cerebral neurosyphilis can mimic acute cerebral infarction, often leading to delayed diagnosis. This case underscores the importance of maintaining a broad differential diagnosis and emphasizes the value of obtaining a thorough social and sexual history, even in elderly patients. Early recognition of this treatable condition can prevent irreversible neurological sequelae. Conclusion: Clinicians should maintain a high index of suspicion for neurosyphilis in elderly patients presenting with new-onset neuropsychiatric or ischemic symptoms. Careful investigation, including serologic testing for sexually transmitted infections, is essential for timely diagnosis and management.