Definition and diagnosis of cytomegalovirus colitis in patients infected by human immunodeficiency virus

The definition and routine diagnosis of cytomegalovirus (CMV) colitis in patients infected by human immunodeficiency virus (HIV) are controversial. In 100 consecutive HIV-infected patients who underwent colonoscopy for the investigation of diarrhea, we compared the yields of routine diagnostic tools for CMV infection and assessed the risk of further CMV organ disease in subgroups of patients with the following features: full evidence of CMV colitis (group 1), colonic CMV infection but no endoscopic lesions (group 2), and no evidence of colonic CMV infection (group 3). All biopsies taken during colonoscopy were examined immediately by routine hematoxylin and eosin (H&E) staining and Viral culture and then pooled for second-line H&E staining and immunohistology. Among the 15 diagnoses of CMV colitis (group 1), two were missed during initial H&E examination, and both patients developed further CMV organ disease during follow-up. Of the 12 group 2 patients, 11 were not receiving anti-CMV drugs at the time of initial colonoscopy. CMV organ disease was not significantly more common in these patients than in group 3 during follow-up. We conclude that routine H&E staining of colonic biopsy specimens for CMV inclusions is not 100% sensitive for CMV colitis. The favorable outcome of colonic CMV infection without endoscopic lesions suggests that only patients with full evidence of CMV colitis warrant specific antiviral therapy.