Objective We aim to present a 45 year-old PVC plant worker with no prior history of mental illness who was admitted to a psychiatric ward with complex neuropsychiatric symptoms. He initially presented to a neurology clinic with a progressive four month history of striking personality change and associated mild cognitive decline, gait ataxia and weight loss. Within a few weeks of presentation, his behaviour had deteriorated, necessitating admission to a psychiatric unit where additional signs of apraxia, dysarthria, visual hallucination, hyper salivation, and profound sleep impairment were noted. After admission, episodes of physical aggression necessitated intensive care treatment. He lacked insight into his abnormal behaviours which included sexual disinhibition.

Method Initial neuropsychology assessment revealed significant impairment in his short-term memory, language, visuospatial orientation and fluency. ACE III score was 61/100.

Results MRI brain normal Cerebral SPECT scan – moderate hypoperfusion in occipital and temporal regions bilaterally, worse on left. Syphilis IgM antibody detected, Serodia Particle aggn REACTIVE >=1:1280 VDRL reactive 1:32, Treponemal ABS positive, CSF: protein 1.2 g/dl, white cells 8 (lymphocytes) EEG: minor changes suggesting diffuse cortical disturbance.

Conclusion He was given a four week course of oral Doxycycline and started empirically on maxepa. He remained compliant with initial significant improvement in verbal fluency, ataxia and apraxia. He continued to exhibit signs of elation with grandiose plans and sexual disinhibition. He was started on 25 mg of lamotrigine which coincided with improvement in mood control allowing discharge home. Two month follow-up revealed an improvement of ACEIII to 87/100. SPECT also showed significant improvement in cerebral perfusion. A repeat lumbar puncture revealed acellular CSF with a marginally raised protein (0.6 g/dl). Functionally, 8 months after presentation, he is back at work full-time. His wife reports only minor residual changes in his personality characterised by a more benign disposition and a mild obsession with household tasks. This case highlights the need to remain vigilant for atypical presentations of neurosyphilis in subjects with complex progressive neuropsychiatric symptoms and behavioural change. A good response to treatment can be anticipated if an early diagnosis is made.