Clinical introduction

A 61-year-old man was referred to our emergency department with unusual behaviour. He presented at work 1 hour too early and according to his colleagues, he appeared unfocussed and neglectful. For the past day, he had experienced fatigue and a mild headache. He was not able to recall any traumatic event and has no chills or fever. On examination, his vital signs were unremarkable. The physical and neurological examination was non-focal, although he was somewhat apathetic and his attention and concentration were diminished. Two lesions on his left middle finger were visible that were slightly sensitive to touch …