Cytomegalovirus Colitis Workup

Updated: May 17, 2021
  • Author: Douglas M Heuman, MD, FACP, FACG, AGAF; Chief Editor: BS Anand, MD  more...
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Laboratory Studies

There is some supportive evidence for testing for cytomegalovirus (CMV) colonic disease to improve sensitivity in suspected CMV colitis cases or in cases of moderate to severe colitis (eg, hematoxylin and eosin staining with immunohistochemistry of biopsy specimens and/or CMV DNA real-time polymerase chain reaction). [11, 12, 13]

Antigen detection

Direct specific immunofluorescent antibody detects viral antigens or viral DNA.

In a retrospective study that evaluated the clinical utility of CMV antigenemia assay and blood CMV polymerase chain reaction (PCR) in 229 patients with moderate to severe ulcerative colitis (UC) to predict CMV colitis and outcomes, Kim et al found both tests had low sensitivity (47.0% and 44.3%, respectively) but high specificity (81.7% and 87.9%, respectively) for diagnosing CMV colitis among the 83 patients (36.2%) with confirmed CMV colitis. [14] There was a significant association between positive CMV antigenemia and subsequent colectomy among patients with CMV colitis (P= 0.015).

Culture techniques

The shell viral assay using monoclonal antibodies can detect immediate early antigens. Shell viral assay cultures reduce the time to positivity to 24-72 hours, whereas other cultures take days to weeks.

Other diagnostic studies

Tests such as antibody tests, qualitative or quantitative PCR, or studies of serum or other body fluids yield less diagnostic information.

Other co-infecting pathogens must be excluded by appropriate smears, cultures, and serologic studies.

A rising alkaline phosphatase level was the initial laboratory abnormality seen in one patient with CMV colitis.


Imaging Studies

Imaging studies may demonstrate bowel wall thickening, mucosal ulcerations (see the following image), and luminal narrowing.

Gross specimen of bowel showing ulceration seconda Gross specimen of bowel showing ulceration secondary to cytomegalovirus colitis.


The study of choice is sigmoidoscopy or colonoscopy, which allows direct visualization and the opportunity to obtain biopsy specimens that may aid in the diagnosis.

Endoscopy may demonstrate mucosal erythema, erosions, ulcerations, hemorrhage, or nodular-plaque or polypoid lesions.

Specimens should be submitted for histologic examination, antigen detection, and viral cultures.

Lesions may mimic neoplastic processes.


Histologic Findings

Affected specimens may show acute and chronic inflammatory changes, vasculitis, and/or mucosal ulceration. Deep biopsy specimens are preferred. Staining with Papanicolaou or hematoxylin and eosin stains may reveal the classic findings, which include giant cells (usually 25-35 µm) (see the image below) with cytomegaly and large ovoid or pleomorphic nuclei containing basophilic inclusions (owl's eyes, halo rim). Data suggest that immunohistochemical staining may be more sensitive for detecting CMV.

Giant cell with inclusion body characteristic of c Giant cell with inclusion body characteristic of cytomegalovirus colitis.