A 59-year-old man presents with dull cramping pain in the right upper abdomen for 3 days. No other symptoms are present. He was diagnosed with type 2 diabetes five years ago, which is well controlled on metformin alone. His surgical and family histories are unremarkable. He smokes heavily, with a total of 15 pack years to date. He also drinks significantly, having consumed 2 to 3 units of alcohol almost every day for the last 10 years. A complete blood count, renal profile, electrolyte assay, and random capillary glucose level are all within normal parameters.