The diagnostic value of endoscopic terminal ileum biopsies

Biopsy of the terminal ileum (TI) is commonly performed during colonoscopy. The primary utility of this is to diagnose or rule out Crohn's disease in patients with symptoms and/or radiographic findings suggesting this diagnosis. We see many such biopsies in our gastrointestinal pathology service and have been impressed by the subjectively low yield of TI biopsies. Therefore, we studied this to obtain objective data.

We retrospectively reviewed 414 consecutive patients with terminal ileal biopsies. Histologic parameters evaluated were primarily those changes diagnostic of chronic inflammation or its sequelae. Histologic findings were then compared with the indication(s) and endoscopic findings.

The TI was histologically normal in 82% and endoscopically normal in 81% with most endoscopic abnormals having "ileitis" (13%). Known or strongly suspected inflammatory bowel disease was the most common indication (38%) with Crohn's disease accounting for 20% and ulcerative colitis 16% followed by diarrhea (33%), anemia/hematochezia (15%), abdominal pain (6%), and abnormal imaging (5%). Diagnostic yield varied, with indication and endoscopic findings being highest with known suspected Crohn's disease (40%), abnormal imaging (32%), and with endoscopic "ileitis" (84%) or ulcers/erosions (69%).

Diagnostic yield of TI biopsy varied with indication and endoscopic findings. Our study indicates that biopsy is of greatest value in patients undergoing endoscopy for known or strongly suspected Crohn's disease, or with an abnormal imaging study of the TI. Biopsy of endoscopically normal mucosa is unlikely to yield diagnostically useful information, and is not encouraged as routine. However, when "ileitis," ulcers, or erosions are identified, biopsies can be very helpful.