Colonic disease associated with a positive assay for Clostridium difficile toxin: a retrospective study.

In this retrospective review of colonic tissue from 21 patients with a positive stool assay for Clostridium difficile toxin, four groups of patients were identified by pathologic examination. Classic pseudomembranous colitis was identified in 38% of patients in colon biopsies, resections, and at postmortem examination. One third of patients had acute colitis without specific features on colon biopsies at the time of a positive toxin assay. Effects of C. difficile toxin in patients with idiopathic inflammatory bowel disease (10%) could not be pathologically separated from activity of the underlying disease. In 19% of patients, no acute or chronic colitis or pseudomembranous colitis was noted. This report reminds gastroenterologists that C. difficile infection is associated with a range of pathologic changes similar to the well known clinical spectrum of disease.