A 53-year-old woman complains of acute diarrhea and severe abdominal pain. She was recently treated with broad-spectrum antibiotics for community-acquired pneumonia. A CBC shows a WBC count of 24,000/mL. The patient subsequently develops septic shock and dies. A portion of her colon is shown at autopsy. These findings are typical of which of the following gastrointestinal diseases?

Pseudomembranous colitis is a generic term for an inflammatory disease of the colon that is characterized by exudative plaques on the mucosa. Antibiotic therapy eliminates the normal mixed flora of the colon and facilitates the overgrowth of Clostridium difficile, leading to an acute infection of the colon. The exotoxins produced by C. difficile cause intestinal necrosis, with superficial ulcers covered by a thick fibropurulent exudate. The other choices are not related to antibiotic therapy and are not associated with the development of these exudative plaques.Diagnosis: Pseudomembranous colitis