Antibiotic-associated pseudomembranous colitis is a potential side effect of antibiotics that should be considered in any such patient who develops diarrhea. Since antibiotic-associated pseudomembranous colitis can involve any part of the colon, the diagnosis cannot be excluded by a normal sigmoidoscopic examination.
Endoscopic evaluation reveals the spectrum from minimal colitis to classic pseudomembranous colitis.
The left side of the colon is most often involved, but a predominantly right-sided colitis is possible. Laboratory diagnosis depends on examination of the feces for the presence of C. difficile toxin. The mere isolation of the organism does not in itself implicate the organism in an ongoing disease process. Rather, given the correct clinical situation, the best test for the diagnosis of antibiotic-associated pseudomembranous colitis is the demonstration of the toxin in the stool. Positive latex tests should be confirmed by another assay when clinically indicated.