Review Question - QID 213376

A 35-year-old man presents to the emergency department for abdominal pain. The patient states that starting last night, he has had severe abdominal pain that is slightly relieved by bowel movements. His stools are grossly bloody. The patient has a past medical history of asthma, anxiety, depression, irritable bowel syndrome, and fibromyalgia. His current medications include albuterol, clonazepam, fluoxetine, gabapentin, and fiber supplements. His temperature is 98.3°F (36.8°C), blood pressure is 100/77 mmHg, pulse is 110/min, respirations are 11/min, and oxygen saturation is 98% on room air. Physical exam is notable for diffuse abdominal tenderness that is the most prominent in the left lower quadrant. An abdominal radiograph with contrast is ordered as seen in Figure A. Colonoscopy is ordered, and a biopsy is taken as seen in Figure B. The patient is started on IV fluids. Which of the following is the best next step in management?