Snapshot An 89-year-old man with a past medical history of gastritis presents to the hospital for dehydration and watery diarrhea. He started having diarrhea and some weakness about 2 days ago and had not been able to keep up with his fluid intake. He has been taking omeprazole for over 30 years and was recently treated with clindamycin for a soft tissue infection. On laboratory evaluation, he has a marked leukocytosis. He is started on oral vancomycin. Introduction Classification login to view 5 more bullets Epidemiology login to view 11 more bullets Pathogenesis login to view 5 more bullets Prognosis login to view 1 more bullet Presentation Symptoms login to view 6 more bullets Physical exam login to view 4 more bullets Imaging Abdominal radiography login to view 5 more bullets Abdominal computed tomography (CT) login to view 6 more bullets Studies Labs login to view 7 more bullets Making the diagnosis login to view 1 more bullet Differential Ulcerative colitis login to view 3 more bullets Crohn disease login to view 4 more bullets Treatment Management approach login to view 1 more bullet Medical login to view 15 more bullets Complications Colonic perforation login to view 1 more bullet Toxic megacolon login to view 1 more bullet