Detection of Cytomegalovirus in Patients with Inflammatory Bowel Disease: Where to Biopsy and How Many Biopsies?

BACKGROUND

The potential negative impact of cytomegalovirus (CMV) in ulcerative colitis (UC) and Crohn's disease (CD) warrants efforts to improve the yield of diagnostic techniques.

METHODS

We retrospectively determined the optimal biopsy location and number from sixty-eight patients with inflammatory bowel disease (66% UC, 31% CD, and 3% inflammatory bowel disease-unclassified) with CMV disease between 2005 and 2011. Biopsies with endoscopic and histologic inflammation were analyzed by immunohistochemistry and/or in situ hybridization. The proportion of positive biopsies was determined, and using data from the 25th percentile, we assessed the number of biopsies required to achieve an 80% probability of a single positive biopsy.

RESULTS

Of the patients with a diagnosis by immunohistochemistry and/or in situ hybridization, 27 of 61 (44%; 95% confidence interval, 32-57) were positive by hematoxylin and eosin, and 11 of 36 (31%; 95% confidence interval, 16-46) had systemic CMV by polymerase chain reaction. Of the patients with biopsies proximal and distal to the splenic flexure, 1 of 11 with UC and 4 of 8 with CD had a diagnosis limited to the right colon. Twenty percent of biopsies were positive by immunohistochemistry or in situ hybridization (20% in UC and 17% in CD). Eleven biopsies in UC and 16 in CD were required to achieve an 80% probability of a positive biopsy.

CONCLUSIONS

Biopsy location and number are important considerations when assessing for CMV. We recommend a flexible sigmoidoscopy with 11 biopsies in UC and a colonoscopy with 16 biopsies in CD.