Abstract Background This case series characterizes enema- and catheter-induced rectal injuries as an underrecognized iatrogenic cause of life-threatening lower gastrointestinal bleeding (LGIB). By focusing on elderly, high-risk patients, we highlight the diagnostic complexities and management strategies associated with these routine yet potentially catastrophic anorectal procedures. Methods We analyzed three cases of high-risk elderly patients who experienced acute, massive hemorrhage following routine anorectal procedures, specifically glycerin enemas and anorectal manometry. To contextualize these findings, we performed a narrative literature review of the PubMed and Web of Science databases to identify recurring clinical characteristics and predisposing factors associated with these iatrogenic rectal injuries. Results All three elderly patients with significant comorbidities experienced sudden, painless, massive hematochezia following routine anorectal procedures. Standard anoscopy failed to localize the bleeding source due to obscuration by extensive blood clots. However, emergency colonoscopy without bowel preparation successfully identified and treated bleeding foci in the distal rectum (3–4 cm from the anal verge). Clinically, the patients demonstrated profound hemoglobin drops ranging from 10 to 80 g/L (nadir: 59 g/L) and severe hemodynamic instability (lowest blood pressure BP: 89/56 mmHg; Heart rateHR: 120 bpm). Two patients required massive blood transfusions, receiving up to 13 units of red blood cells and 1,350 mL of fresh frozen plasma to maintain stability. Notably, all three patients required Intensive care unit (ICU) admission for intensive monitoring and resuscitation. Common risk factors identified included advanced age, prolonged bed rest, and underlying coagulopathy. Conclusion In frail, bedridden patients, even routine anorectal procedures such as enema administration or catheterization can trigger catastrophic, life-threatening hemorrhage. While instrumentation is the primary trigger, clinical outcomes depend on recognizing potential mucosal vulnerability. The key to survival lies in early risk stratification, maintaining a high index of clinical suspicion regarding recent procedural history, and proceeding directly to emergency colonoscopy to identify and treat hidden bleeding sources in the distal rectum. Such vigilance is not merely best practice—it is life-saving and should be formally integrated into clinical guidelines to enhance safety for high-risk populations.
Yin et al. (2026) studied this question.