C. Crohn’s disease

A 50-year-old woman has had a long history of medical problems including chronic abdominal pain, hypertension, obesity and obstructive pulmonary disease. She presents to the emergency room with acute right-sided abdominal pain, diarrhea and some bright red blood in the stools. She is admitted to hospital, treated with fluids and empiric antibiotics are given, though stool cultures are negative. Colonoscopy shows two segments of colitis in the ascending colon and cecum [FIGURE]. The most likely diagnosis is: A. C. difficile coliti