Development of nonantibiotic-associated
pseudomembranous colitis has been reported in patients receiving
chemotherapy. Herein, we report a case of a 70-year-old man with
diabetes mellitus and
hypertension who received concurrent chemoradiation
therapy after surgery for stage III pT3N1M0
rectal cancer. After completion of the
therapy, the patient presented with a 2-week history of intermittent watery
diarrhea (seven to nine times per day). However, the patient was afebrile and laboratory examination revealed no evidence of
leukocytosis. Computed tomography disclosed
inflammation of the sigmoid colon, infiltrative changes around the anastomotic site, and edematous changes straddling the serosal surface. Colonoscopic examination revealed multiple whitish patches within the radiation field, a finding suggestive of
pseudomembranous colitis. No concomitant
antibiotics were used during the period of concurrent chemoradiation
therapy. Empirical oral
metronidazole (500 mg every 8 hours) was administrated for 2 weeks. At the end of this treatment, stool culture was negative for Clostridium difficile. Physicians should be aware of the potential for the development of
pseudomembranous colitis following concurrent chemoradiation
therapy.