From the Guidelines
Lower gastrointestinal (GI) bleeding is most commonly caused by diverticulosis, accounting for approximately 30% of cases, followed by other conditions such as inflammatory bowel disease, neoplasms, and vascular lesions like angiodysplasia. The causes of lower GI bleed can be diverse, ranging from benign conditions like hemorrhoids to more serious diseases such as colorectal cancer. According to the study by 1, diverticulosis is the leading cause of lower GI bleeding, with approximately 75% of episodes due to diverticulosis stopping spontaneously, especially in patients requiring transfusions of less than 4 units of blood over a 24-hour period.
Common Causes of Lower GI Bleed
- Diverticulosis: small pouches in the colon wall that can bleed when inflamed
- Inflammatory bowel disease: conditions like Crohn's disease or ulcerative colitis
- Neoplasms: colorectal polyps or cancer
- Vascular lesions: angiodysplasia, which involves abnormal blood vessels in the colon
- Hemorrhoids: swollen veins in the rectum or anus that may rupture
- Ischemic colitis: reduced blood flow to the colon
- Radiation proctitis: following radiation therapy
The study by 1 provides a comprehensive review of the management of lower GI bleeding, highlighting the importance of age as a factor, with diverticulosis and angiodysplasia more common in older adults. The severity of bleeding can vary widely, from minor to massive hemorrhage, and diagnosis typically involves colonoscopy to allow direct visualization and potential treatment of the bleeding source. It is essential to prioritize the most recent and highest quality study, which in this case is 1, to guide clinical decision-making and ensure the best possible outcomes for patients with lower GI bleeding.
From the Research
Causes of Lower GI Bleed
The causes of lower GI bleed can be diverse and include:
- Diverticular disease 2, 3, 4, 5
- Vascular ectasia 2, 3, 4
- Ischemic, inflammatory or infectious colitis 2
- Colonic neoplasia (including post polypectomy bleeding) 2, 3
- Anorectal causes (including haemorrhoids, fissures and rectal varices) 2
- Small bowel lesions (Crohn's, vascular ectasia, Meckel's diverticula, and small bowel tumours) 2
Factors Associated with Lower GI Bleed
Factors associated with the development of acute lower GI bleeding include:
Diagnosis and Evaluation
Colonoscopy is the single most frequent intervention in evaluating patients with lower GI bleeding 2, 6, 5. Determining the precise impact of colonoscopy on the outcome of lower GI bleeding is difficult due to the retrospective nature of many studies, and the frequent inability to definitively establish the exact bleeding site 2. Other diagnostic tests, such as computed tomography angiography (CTA), may also be used in certain cases 6.