Colitis Caused by Escherichia Coli 01587:H7: A Study of Six Cases

The clinical and pathologic features of six patients with provenverotoxin-producing Escherichia coli colitis are described. Clinical data, 25 biopsyspecimens and two autopsies from these patients are reviewed. All presented withcrampy abdominal pain and bloody diarrhea. Colonoscopic findings includededema, erythema, pseudomembranes and hemorrhage. On biopsy, two patientshad ischemic colitis, one had pseudomembranous colitis and three had a combination of concurrent ischemic and pseudomembranous colitis. Four casesshowed fibrin-platelet thrombi in mucosal capillaries and submucosal arterioles.The classical pattern of infectious colitis was not seen in these cases. Othernonspecific changes included patchy mucosal edema, congestion, focallyprominent interstitial hemorrhage and mild, patchy increase of the lymphoplasmocyticcomponent of the lamina. Ischemic necrosis was present in 10 of 25biopsies (40%), pseudomembranes in seven of 25 biopsies (28%), and four of 25biopsies (16%) showed both. Colon from one autopsy revealed edema, pseudo membranesand intramural infarction . Concurrent thrombotic thrombocytopenicpurpura was clinically documented in three of six patients. It isconcluded that, in the context of hemorrhagic colitis, the following observationsare indicative of E coli 0157:H7: the combination of pseudomcmbranous andischemic colitis; ischemic colitis in a young patient; or pseudomembranous colitiswith Clostridium difficile-negative culture and toxin. Multiple biopsies are requiredto demonstrate the full-blown features. E coli 0157:H7 colitis should beadded to the differential diagnosis of submucosal edema