An Unusual Cause of Lower Gastrointestinal Bleeding in Crohn's Disease


Question: A 62-year-old woman with an 8-year history of fistulizing ileocolonic Crohn's disease (CD) presented to our institution with profuse bleeding from a perianal fistula. The patient has been maintained on oral 5-aminosalicylic acid (5-ASA) since diagnosis and 6-mercaptopurine (6MP) 100 mg/d for the previous 8 months. The patient complained of sudden-onset bleeding from her perianal fistula. Her blood pressure was 105/60 mmHg and pulse rate 102, bpm. Her perianal examination was significant for pyoderma gangrenosum on the skin of her buttock (Figure A) and a large perianal fistula with active bleeding. Digital rectal examination was significant for a nodular and hard rectal mucosa with a palpable stricture above the dentate line. Blood work was significant for a hemoglobin of 9.6 g/dL (baseline, 11 g/dL) and a white blood cell count of 3.6/L. The remainder of her laboratory work was within normal limits.

After resuscitation, the patient was taken to the operating room for an examination under anesthesia and intraoperative colonoscopy. On colonoscopy, the patient's rectum appeared dusky and nodular and was also firm and friable (Figure B) in a continuous fashion up to 25 cm proximally at which point there was 15 cm of intact mucosa, followed by 15 cm of dusky mucosa in the sigmoid colon (Figure C). Despite an atypical presentation, the endoscopist was concerned that this represented ischemia/infarct. The remainder of the proximal colon and terminal ileum seemed normal. By the time the colonoscopy was performed, the bleeding had stopped, although it was apparent that the bleeding had come from the distal colon/rectum. The internal fistula opening was not identifiable on colonoscopy. Biopsies were obtained from throughout the colon and the patient was transferred back to the inpatient ward for further care. Contrast computed tomography (CT) was performed, revealing active inflammation from the descending colon to the rectum with ongoing inflammation in the known fistula and evidence of a perianal abscess (Figure D). The colonoscopy photos from 1-year prior were retrieved and compared. At that time, there was moderate colitis in the rectosigmoid area and a rectal fistula opening identified (Figure E).

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