Purpose: Cytomegalovirus infection has been known to complicate ulcerative colitis. This study was designed to elucidate the prevalence and clinical features of ulcerative colitis that might point efficiently to the diagnosis of complicating cytomegalovirus infection in cases of ulcerative colitis.

Methods: The study included 47 consecutive patients diagnosed to have moderate-to-severe ulcerative colitis who were treated on an inpatient basis at our department during a two-year period. A prospective examination for cytomegalovirus antigenemia was conducted in all patients with moderate-to-severe ulcerative colitis to determine the prevalence of cytomegalovirus infection among these patients. Then, the characteristic clinical and endoscopic features of ulcerative colitis complicated by cytomegalovirus infection were investigated by comparison of the cytomegalovirus-infected group with the non-cytomegalovirus-infected group. The therapeutic effects of antiviral drugs also were assessed.

Results: Cytomegalovirus infection was detected in 16 of 47 patients (34 percent). Proportion of female patients, age at the time of determination, and proportion of patients showing corticosteroid resistance was significantly higher in the cytomegalovirus-infected group (59.1 percent) than in the non-cytomegalovirus-infected group (13.6 percent). The prevalence of endoscopically severe ulcerative colitis was higher in patients with cytomegalovirus antigenemia than in those without cytomegalovirus antigenemia (P = 0.016). Ganciclovir was administered to 12 of 16 ulcerative colitis patients with complicating cytomegalovirus infection, and was found to be effective in 8 (66.7 percent).

Conclusions: It is not easy to make a diagnosis of cytomegalovirus infection complicating ulcerative colitis based on clinical features, including endoscopic biopsy. On the other hand, blood examination for the detection of cytomegalovirus antigenemia in corticosteroid-resistant patients, particularly in relatively elderly patients, may enable diagnosis of cytomegalovirus infection with a high sensitivity and allow effective treatment to be administered in these patients.