Management of Rectal Bleeding

Diagnostic Approach

The American Gastroenterological Association recommends that patients over 50 with unexplained rectal bleeding undergo colonoscopy within 2 weeks, as they have a 6% risk of underlying bowel cancer 1, 2
Perform a complete history and physical examination, including digital rectal examination (DRE), to assess for anorectal pathology and confirm the appearance of blood 3, 1
Check vital signs and calculate the shock index to identify active bleeding—a shock index >1 indicates hemodynamic instability 1
Order complete blood count and coagulation studies if severe bleeding is suspected 4

Calculate the Oakland score using age, gender, previous lower GI bleeding admission, DRE findings, heart rate, systolic blood pressure, and hemoglobin level to determine the risk of major bleed 1, 2
An Oakland score ≤8 indicates a minor self-terminating bleed, while a score >8 indicates a major bleed requiring hospital admission 1, 2

Colonoscopy is the preferred initial investigation for hemodynamically stable patients, with diagnostic yields of 42-90% 2, 5
Assessment of the anal canal and rectum should be performed using proctoscopy, rigid sigmoidoscopy, or flexible endoscopic examination to evaluate for anorectal conditions 1, 2
For hemodynamically unstable patients, perform CT angiography (CTA) first to rapidly localize the bleeding site, with sensitivity of 79-95% and specificity of 95-100% 5, 6

Diverticulosis is a common cause of acute lower GI bleeding in patients over 50 years, though the patient's age (55 years) is slightly younger 9
Hemorrhoids and anorectal conditions account for 16.7% of lower GI bleeding diagnoses and are frequently identified 1, 2
Colorectal cancer and polyps account for 6-27% of acute lower GI bleeding cases, with cancer risk of 2.4-11% in patients with rectal bleeding over age 40 7, 8, 9
Angiodysplasia accounts for 2-40% of cases, with incidence increasing with age 9
Inflammatory bowel disease (ulcerative colitis, Crohn's disease) should be considered, particularly if associated with diarrhea, abdominal pain, or weight loss 3

Approximately 80-85% of lower GI bleeding stops spontaneously, but 50% of patients with diverticular bleeding require blood transfusion 9