A 64-year-old woman presentsto the emergency department withworsening crampy abdominal painthat began the night before. Afterthe pain started, she had a bowelmovement containing a significantamount of blood; since then she hashad episodes of diarrhea. She hadbeen previously healthy, denies traumaand fever, and knows no one withsimilar symptoms. She reports norecent enema, endoscopy, or otherabdominal procedure.
