An 84-year-old man was admitted for a pyogenic liver abscess and was treated with intravenous ceftriaxone and oral metronidazole 500 mg three times per day. The treatment proved effective; however, five weeks after the start of the treatment, headaches, symmetric distal dysesthesia in the extremities, and altered consciousness developed. A neurological examination revealed dysarthria, gait instability, anesthesia in the distal extremities, and limb dyscoordination. The rest of the physical examination was otherwise unremarkable.