Cytomegalovirus Colitis Evaluation and Management

Immunosuppression History

The Centers for Disease Control and Prevention recommends asking about HIV/AIDS status, as HIV-positive patients are at increased risk for severe CMV infections 1, 2
Patients with a history of organ transplantation, particularly liver transplants, have a 4.9% 10-year cumulative incidence of post-transplant CMV end-organ disease, and hematopoietic stem cell transplantation has a 15-25% incidence of CMV end-organ disease 1, 3
Current immunosuppressive medications, especially corticosteroids, azathioprine, or methotrexate, are significantly associated with CMV disease (OR: 1.95; 95% CI: 1.05–3.62) 4
Anti-TNF therapy is an independent risk factor for CMV colitis (OR: 11.13; 95% CI: 3.31–37.44) 4
Patients with inflammatory bowel disease (IBD) presenting with CMV colitis may experience up to seven times higher in-hospital mortality 1, 3

Diarrhea is a common nonspecific symptom of CMV colitis 1, 3
Rectal bleeding may indicate colonic involvement 1, 3
Abdominal pain, particularly its location, severity, and duration, should be assessed 1, 3
Weight loss may indicate chronic disease 1, 3
Fever is a common symptom in CMV infection 1

Steroid-refractory disease is associated with higher prevalence of CMV disease 4
Recent antibiotic use may affect differential diagnosis 5
Sudden onset of symptoms may suggest infectious colitis rather than IBD flare 5
Exposure to individuals with known CMV infection increases the risk of acquiring CMV infection, as CMV is shed in bodily fluids 2
Working in childcare facilities increases the risk of acquiring CMV infection 2

Classical CMV viremia symptoms (pharyngitis, lymphadenopathy, splenomegaly) are usually absent in CMV colitis 1, 3
Recent respiratory infections can be associated with mesenteric lymphadenitis 6
Recent travel history may suggest other infectious causes 6
Symptoms of other viral infections that may mimic or coexist with CMV (e.g., EBV, Coxsackievirus) should be considered 6

Previous colonoscopies and findings, particularly if ulcerations with well-defined, punched-out appearance were noted (present in up to 80% of patients), should be assessed 1, 3
Previous treatments for similar symptoms and their effectiveness should be evaluated 4, 7
Previous CMV testing and results, including blood serology (though this has limited diagnostic value), should be considered 1, 3

Signs of toxic megacolon, fulminant colitis, or perforation require emergency surgical intervention 3, 8
Symptoms suggesting disseminated CMV infection would necessitate discontinuation of immunosuppressive therapy 7
Symptoms of intestinal obstruction or severe abdominal pain may require emergency surgical assessment 9

Blood serology has no diagnostic value for CMV colitis, as CMV seroprevalence in adults is at least 70% 1, 3
Patients with CMV colitis usually do not present with classical CMV viremia symptoms 1, 3
Culturing CMV from a biopsy is insufficient for diagnosis without histopathological changes, as some immunocompromised patients may have positive cultures without clinical disease 2

The European Crohn's and Colitis Organisation recommends diagnosing CMV colitis using colonoscopy with multiple biopsies analyzed by immunohistochemistry (IHC), which has a sensitivity of 78-93% and specificity of 98.7%, supplemented by tissue PCR when IHC is negative but clinical suspicion remains high 10, 11
The American Gastroenterological Association suggests that patients with steroid-refractory inflammatory bowel disease (IBD), particularly ulcerative colitis with acute severe flares, are at high risk for CMV disease, with an odds ratio of 4.24 10
The Infectious Diseases Society of America recommends that patients on multiple immunosuppressants, such as azathioprine/methotrexate or anti-TNF therapy, be screened for CMV colitis, as they are at increased risk of developing the disease 10, 12

The Centers for Disease Control and Prevention recommend performing colonoscopy with extensive biopsy sampling as the cornerstone of diagnosis, with a minimum of 11 biopsies for ulcerative colitis and 16 biopsies for Crohn's disease 13, 10, 11
The American Society for Gastrointestinal Endoscopy suggests that biopsy location matters, with target ulcer bases and edges where CMV-positive cells are most concentrated 12
The European Society of Clinical Microbiology and Infectious Diseases recommends using tissue PCR as an adjunct to IHC, with a suggested cutoff of >250 viral copies/mg tissue 12

The American College of Gastroenterology recommends that definitive CMV colitis requires mucosal ulcerations on endoscopy plus characteristic intranuclear and intracytoplasmic "owl's eye" inclusions on histology or positive IHC showing CMV-infected cells 13, 11, 10
The Infectious Diseases Society of America suggests that CMV reactivation without disease usually does not require treatment, but patients with positive tissue PCR alone without histological inflammation or positive blood PCR without tissue confirmation should be monitored closely 10, 12

In patients with advanced HIV infection who have a positive CMV PCR (blood or stool) and diarrhea, performing a colonoscopy with multiple biopsies is required to confirm CMV colitis and to direct antiviral therapy, because PCR positivity alone cannot differentiate asymptomatic viral shedding from true end‑organ disease. 14, 15, 16

The 2017 Infectious Diseases Society of America (IDSA) guidelines state that “colonoscopy with biopsy for CMV enteritis” is a mandatory investigation for HIV‑infected individuals presenting with diarrhea, and it should be performed in addition to stool studies. (Strong recommendation) 14, 15, 16