Cytomegalovirus infection associated with onset of ulcerative colitis

BACKGROUND: In 2009, a trigger role of cytomegalovirus (CMV) was shown in the development of ulcerative colitis (UC) in mice. Fifteen cases of synchronous onset of CMV colitis and UC have been reported in literature. A careful prospective and retrospective survey identified CMV colitis in newly diagnosed UC patients at 4.5% (3/65 cases) and 8.2% (5/61 cases), respectively. This means that a majority of synchronous CMV colitis may be missed in newly diagnosed UC patients in routine practice. Such a case is presented. CASE PRESENTATION: A 50-year-old woman, with a history of right partial mastectomy two years ago, had a persistent high fever for 9 days, after which a thickness of the colonic wall was detected on abdominal ultrasonography. Laboratory data showed inflammation and 2% atypical lymphocytes with the normal number of white blood cells. Although there was no bloody stool, fecal occult blood was over 1000 ng/ml. Colonoscopy showed diffuse inflammation in the entire large bowel and pseudomembranes in the sigmoid colon. The diagnosis was UC with antibiotic-associated pseudomembranous colitis. Metronidazole followed by sulfasalazine resulted in defervescence and improvement in laboratory data of inflammation. It took one month for normalization of fecal occult blood. Endoscopic remission was simultaneously confirmed. Later, it was found that a report of positive CMV antigenaemia (2/150,000) had been missed. Reevaluation of biopsy specimens using a monoclonal antibody against CMV identified positive cells, although inclusion bodies were not found in hematoxylin and eosin sections. Finally, the case was concluded to be synchronous onset of CMV colitis and UC. CONCLUSION: Synchronous CMV colitis is not routinely investigated in newly diagnosed UC patients. Together with a recent observation in animal studies, it is plausible that a subset (a few to several per cent) of UC patients develop synchronous CMV infection. Further studies are needed to elucidate the plausibility.