S5123 Acute Lower Gastrointestinal Hemorrhage From Cytomegalovirus Colitis Leading to Severe Anemia

Introduction: Cytomegalovirus (CMV) colitis is an opportunistic infection predominantly affecting immunocompromised individuals. The clinical presentation of CMV colitis is often nonspecific, including symptoms such as diarrhea, abdominal pain, and fever. Although gastrointestinal bleeding is a recognized complication of CMV colitis, the development of severe acute anemia from substantial hemorrhage remains a rare but serious clinical scenario. Case Description/Methods: We report a case of a 52-year-old man with a medical history of human immunodeficiency virus (HIV) who presented to the emergency department with complaints of ongoing rectal bleeding for 3–4 weeks, associated with progressive dizziness and shortness of breath. Initial evaluation revealed significant anemia. The patient underwent esophagogastroduodenoscopy (EGD) and colonoscopy to investigate the source of bleeding. EGD was unremarkable; however, colonoscopy revealed a diffusely congested, erythematous, eroded, hemorrhagic, and inflamed mucosa throughout the colon. Biopsy of the sigmoid colon demonstrated histopathological features consistent with CMV colitis. Discussion: This case highlights the importance of considering CMV colitis in the differential diagnosis of gastrointestinal bleeding and anemia in immunocompromised patients, especially those with HIV. Early recognition and diagnosis are critical for timely initiation of antiviral therapy and improved patient outcomes.