Symptoms of CMV Colitis
CMV colitis presents with nonspecific gastrointestinal symptoms including diarrhea, rectal bleeding, fever, abdominal pain, and weight loss, with life-threatening complications including massive hemorrhage and colonic perforation. 1
Clinical Presentation
Common Symptoms
- Diarrhea (often debilitating and persistent) 1
- Rectal bleeding (ranging from occult blood to massive hemorrhage) 1
- Fever (frequently present) 1
- Abdominal pain (variable location and severity) 1
- Weight loss and anorexia (indicating chronic disease burden) 1
- Malaise (generalized weakness and fatigue) 1
Absence of Classic CMV Viremia Symptoms
Patients with CMV colitis typically do NOT present with the classic CMV viremia triad of pharyngitis, lymphadenopathy, and splenomegaly. 1, 2 This is a critical diagnostic pitfall—the absence of these systemic symptoms should not exclude CMV colitis from your differential diagnosis.
Life-Threatening Complications
Surgical Emergencies
- Toxic megacolon (requires emergency colectomy) 1, 3
- Colonic perforation (surgical emergency with high mortality) 1
- Fulminant colitis (rapidly progressive bowel wall necrosis) 1, 3
- Extensive mucosal hemorrhage (can be life-threatening) 1
- Bowel ischemia (from CMV-induced vasculitis) 1
High-Risk Populations
Immunocompromised Patients
CMV colitis occurs predominantly in severely immunosuppressed individuals:
- HIV/AIDS patients with CD4+ counts <50 cells/µL 1
- Solid organ transplant recipients (4.9% 10-year cumulative incidence post-liver transplant) 1, 2
- Hematopoietic stem cell transplant recipients (15-25% incidence of CMV end-organ disease) 1, 2
- Patients on immunosuppressive therapy (corticosteroids, azathioprine, methotrexate—OR 1.95) 2
- Anti-TNF therapy recipients (OR 11.13 for CMV colitis) 2
- Patients with malignancies (particularly acute lymphoblastic leukemia in pediatrics) 1
Inflammatory Bowel Disease Association
Patients with IBD who develop CMV colitis experience up to seven times higher in-hospital mortality compared to CMV colitis alone. 1, 2 Steroid-refractory IBD is particularly associated with CMV reactivation. 2, 4
Endoscopic Findings
Characteristic Ulcer Appearance
- Punched-out ulcerations with well-defined borders (present in up to 80% of cases) 1, 2
- Cecal ulcers involving the ileocecal valve (specific finding in graft-versus-host disease patients) 1
- Pancolic involvement is rare (helps differentiate from Clostridioides difficile colitis) 1
Mortality Risk
In-hospital mortality of immunocompromised patients with severe CMV colitis approaches or exceeds 70% even with treatment. 1, 5 This extraordinarily high mortality rate underscores the critical importance of early recognition and aggressive management.
Diagnostic Pitfalls to Avoid
Blood Serology Has No Value
CMV blood serology is diagnostically useless for CMV colitis, as at least 70% of adults are CMV seropositive. 1, 2 Do not order or rely on CMV IgG/IgM antibodies for diagnosis.
Diagnosis Requires Tissue Confirmation
- CMV-specific immunohistochemistry on colonic biopsies is the gold standard (sensitivity 78-93%, specificity 92-100%) 1, 3
- "Owl eye" inclusion bodies on hematoxylin-eosin staining are highly specific but less sensitive 1
- Colonic tissue CMV DNA PCR improves sensitivity (use viral load cut-off >250 copies/mg tissue for clinical significance) 3
Imaging Findings
Contrast-enhanced CT demonstrates bowel wall thickening (almost always present) with small bowel involvement in up to 40% of cases. 1 Pancolic thickening is rare and helps distinguish CMV colitis from C. difficile colitis.