Self-Limited Gastrointestinal Illness With Positive Cytomegalovirus Serology in a Young Immunocompetent Adult: A Case Report

Cytomegalovirus (CMV) colitis is uncommon in young immunocompetent individuals, and distinguishing systemic CMV infection from tissue-invasive colonic disease can be challenging.A 28-year-old immunocompetent male patient presented with fatigue, nausea, postprandial left lower quadrant abdominal pain, watery nonbloody diarrhea, decreased oral intake, and weight loss.Laboratory testing showed lymphocytosis and elevated transaminases, while an abdominal computed tomography report described mild splenomegaly and nonspecific colonic changes potentially associated with inflammation.CMV IgM and IgG were positive, and Epstein-Barr virus (EBV) serologies were also positive, although EBV blood polymerase chain reaction (PCR) was negative.CMV quantitative PCR, stool pathogen studies, and colonoscopic biopsy were not obtained during the acute illness.Symptoms resolved without antiviral therapy.Delayed colonic biopsies showed benign mucosa without evidence of CMV infection.Thus, the patient's gastrointestinal illness occurred in association with positive CMV serology, but the absence of acute-phase virologic and histopathologic evidence prevents establishing that CMV caused the colonic abnormalities.This case highlights the diagnostic limitations of attributing a self-limited gastrointestinal illness to CMV without tissue confirmation and adequate evaluation for alternative enteric infections.