3159 Neurosyphilis presenting as facial palsy, encephalopathy and gelastic seizures

CaseA 67-year-old man developed left facial weakness, treated with oral prednisolone and acyclovir for Bell’s palsy. A week later, he was brought in by police in a confused state. He had a rash, was febrile, agitated, hallucinating, shouting for his dog, and intermittently laughing hysterically. C-reactive protein was 300 mg/L, white cell count 17 x10^9/L. Cranial MRI showed a thin subdural collection containing blood products over the left temporal convexity, inflammatory changes in the left facial nerve, and subtle regions of normalizing cortical DWI change in bilateral frontal and left mesial temporoparietal regions, considered post-ictal changes. Cerebrospinal fluid (CSF) showed 14 white cells, a mildly elevated protein (0.96 g/L), glucose 12.4 mmol/L, negative viral serology, normal cytology and no oligoclonal bands. EEG showed 1–2Hz continuous left periodic epileptiform discharges over left frontal/frontocentral regions. Serum syphilis serology returned positive for both TPPA and EIA at a titer of 1:128. Human immunodeficiency viral serology was negative. Autoimmune encephalitis antibodies (NMDA, LGI1, CASPR2, AMPA1, AMPA2, GABA, paraneoplastic panel) were negative.Management/OutcomeA diagnosis of neurosyphilis with gelastic seizures was made. He was treated with intravenous benzylpenicillin and oral levetiracetam and sodium valproate. Within days, he was conversant and only mildly confused, with no further laughing episodes.ConclusionThis case highlights the importance of considering neurosyphilis in a variety of neurological presentations, in this case encephalopathy, facial nerve palsy and gelastic seizures localizing to the frontal lobe. Neurosyphilis is increasing in prevalence and is treatable.