People who have C. difficile may have symptoms such as abdominal pain and fever or loose stools that contain mucus or blood. In some cases, patients may have a ruptured colon. C. difficile usually appears within one to two weeks of starting an antibiotic (even just one dose before surgery). It can be distinguished from noninfectious, antibiotic-induced diarrhea which usually ends when antibiotic use stops.
It is important to diagnose C. difficile as early as possible and begin aggressive treatment to avert complications such as dehydration, electrolyte depletion, even hemorrhage. Stool tests are the standard diagnostic method. A flexible sigmoidoscopy, which focuses on the lower part of the colon, may provide a quicker diagnosis so that therapy can begin sooner, before stool results are available. A colonoscopy also may be used.