Cytomegalovirus Colitis

Excerpt

Cytomegalovirus (CMV) is a double-stranded DNA virus and a member of the human herpesvirus family. It is a common viral infection in 50% to 100% of humans worldwide, depending on the age and race of the population tested. This activity discusses current approaches to diagnose and manage CMV colitis. The CMV genome is the largest among human viruses (approximately 230 kb), containing 200 genes encoding proteins. In healthy subjects, CMV colitis is usually asymptomatic or causes self-limited disease but may result in chronic infection or a life-long carrier state with intermittent reactivation. Cytomegalovirus reactivation is frequent in severe or corticosteroid-resistant ulcerative colitis. However, what science does not yet know is whether CMV causes exacerbation of ulcerative colitis or simply serves as an innocent bystander of severe disease. Patients with CMV colitis present with non-specific symptoms, including diarrhea, abdominal pain, fever, rectal bleeding, and weight loss. Hematochezia and diarrhea are the most frequently observed symptoms in these patients. Therefore, a high index of suspicion is necessary, and laboratory investigations are essential in diagnosing CMV colitis. Several methods are possible, including antigenemia, endoscopy, histological examination of biopsy tissues, CMV culture, and tissue polymerase chain reaction (PCR) quantification. Colonic mucosal biopsies stained with hematoxylin and eosin (H & E) may reveal the typical inclusion associated with CMV colitis, “owl eye appearance” inclusion bodies, which are highly specific for CMV. However, H & E staining has low sensitivity compared to immunohistochemistry, which is the gold standard for diagnosing CMV colitis. Rapid diagnosis and management are usually recommended, especially in critically ill patients.