A 69-year old White British gentleman presented with a week's history of drowsiness, confusion, sweats and olfactory hallucinations with poor appetite, nausea and vomiting. He was sweaty and confused with poor attention. There was visible focal and complex partial seizure activity.
An MRI brain showed right medial temporal lobe signal change. A CSF showed 90 white cells (90% lymphocytes) and raised protein of 0.90. He was treated with aciclovir for presumed HSV encephalitis. The CSF viral PCR was negative. A repeat CSF showed similar results with negative PCR. He developed an erythematous maculopapular rash over his trunk. A screen for autoimmune and paraneoplastic encephalitis was negative.
A positive serum VDRL result was later received with positive RPR and TPPA titres, consistent with a diagnosis of recent treponemal infection. CSF Syphilis IgG, RPR and TPPA were also positive. He was treated for 21 days with high dose IV penicillin.
Neurosyphilis was thought to be almost extinct in the non-HIV population. It has been reported infrequently in the literature as a clinical and radiological mimic of HSV encephalitis. We review the literature surrounding neurosyphilis and this presentation. We recommend VDRL testing in all patients presenting with uncharacterized encephalitis.