Review Question - QID 107300

A 67-year-old woman with a recently found hepatic carcinoma has been an inpatient for more than a week. During morning rounds, she was abnormally disoriented to time and place along with a shortened attention span. The overnight resident reports that she was coming in and out of this state for the past couple nights. The patient was known to drink often, but reported that she has not consumed alcohol in weeks leading up to her admission. She is not jaundiced and has no metabolic imbalance upon laboratory tests. What is the most likely cause of her recent mental impairment?