2020 Oct 16. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–.
ABSTRACT
Cytomegalovirus (CMV), a double-stranded DNA virus and a member of the human herpesvirus family, is a common viral infection in 50% to 100% of humans worldwide depending on age and race of population tested. This chapter discusses current approaches to diagnose and manage CMV colitis and how to make a high index of suspicion based on clinical presentation and use investigation methods to reach a final diagnosis. 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 steroid-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 suspicion index is necessary, and laboratory investigations are essential in making the diagnosis of 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 the diagnosis of CMV colitis. Rapid diagnosis and management are usually recommended, especially in critically ill patients.