Concurrent amebic and cytomegalovirus colitis in immunocompromised patients: two case reports and literature review

Immunosuppression from human immunodeficiency virus (HIV) or other comorbidities increases susceptibility to gastrointestinal infections such as Entamoeba histolytica and cytomegalovirus (CMV). Although each pathogen can independently cause severe colitis, co-infection is rare and may lead to rapid clinical deterioration if not recognized early. We report two cases of concurrent amebic and CMV colitis in immunocompromised patients. The first patient, a 56-year-old man with HIV, Kaposi sarcoma, and hepatitis C, presented with bloody diarrhea and hypotension. Colonoscopy revealed pancolitis with ulcerations, and biopsy initially confirmed E. histolytica. Despite an initial response to anti-amebic therapy, he later developed recurrent bleeding and sepsis and died on hospital day 24. Postmortem pathological examination subsequently identified CMV co-infection. The second patient, a 48-year-old HIV-negative man with diabetes, chronic hepatitis B and C, and prior colorectal cancer, presented with 1 month of bloody diarrhea. Colonoscopy and histopathology confirmed dual infection, which was successfully treated with metronidazole and ganciclovir. A follow-up colonoscopy later demonstrated complete resolution. These cases highlight the importance of early endoscopic evaluation and tissue diagnosis in immunocompromised patients with persistent bloody diarrhea, as prompt recognition of co-infection allows timely, targeted therapy and may prevent fatal outcomes.