Ulcerative colitis Quiz: Ace Your Exams

A 28-year-old man is brought to the emergency department with lethargy and severe abdominal pain since yesterday. He has had 4-5 episodes of small-volume bloody diarrhea per day accompanied by lower abdominal cramps for the past 2 months. Review of systems reveals a 4-kg (8.8-lbs) weight loss and loss of appetite. The remainder of his history is noncontributory. Temperature is 38.8°C (102°F), pulse is 125/min, respirations are 18/min, and blood pressure is 90/55 mmHg. Physical examination shows lethargy and dry mucous membranes. There is abdominal distension, diffuse abdominal tenderness, and decreased bowel sounds without rebound or guarding. Rectal examination reveals marked tenderness, with guaiac-positive, maroon-colored, liquid stools in the vault. Laboratory results are shown below:

Laboratory value	Result
Complete blood count
Hemoglobin	9.9 g/dL (reference range: 13.5-17.5 g/dL)
Platelets	455,000/mm3 (reference range: 150,000-400,000/mm3)
Leukocytes	19,200/mm3 (reference range: 4,500-11,000/mm3)
Erythrocyte sedimentation rate	67 mm/hr (reference range: 0-15 mm/hr)

Fluid resuscitation with 0.9% normal saline improves the blood pressure to 103/59 mmHg. Which of the following is most likely to be found on further evaluation?