Review Question - QID 109668

A 42-year-old female with Crohn disease undergoes resection of the terminal ileum and right hemicolectomy due to refractory symptoms. While recovering postoperatively, she is started on total parental nutrition (TPN). She has an uncomplicated postoperative course and is discharged home after 3 days. The patient continues to receive TPN to allow for bowel rest with a plan to transition to enteral nutrition after several weeks. She presents to the emergency department after one week complaining of moderate right upper quadrant pain that comes and goes. Her temperature is 98.5°F (36.9°C), blood pressure is 126/81 mmHg, pulse is 75/min, and respirations are 13/min. Cardiopulmonary exams are unremarkable, her incision is well healed, and her abdomen is tender in the right upper quadrant without rebound or guarding. A right upper quadrant ultrasound is performed with findings shown in Figure A. Which of the following is the most likely cause of this patient’s ultrasound findings?