Management of Rectal Bleeding
All patients presenting with rectal bleeding require a digital rectal examination and risk stratification based on hemodynamic status, with colonoscopy being the definitive diagnostic test for most patients, particularly those over 40 years of age where serious pathology is detected in up to 44% of cases. 1, 2
Initial Assessment and Hemodynamic Stabilization
Assess hemodynamic status immediately by checking pulse, blood pressure, and orthostatic vital signs to determine bleeding severity 1. Obtain complete blood count, coagulation studies (INR), and serum creatinine 3, 1.
Risk Stratification Using Oakland Score
- Score ≤8 points: Safe for outpatient management 1
- Score >8 points: Major bleed requiring hospital admission 1
- Score incorporates: age, gender, previous lower GI bleeding, digital rectal exam findings, heart rate, systolic blood pressure, and hemoglobin level 1
Resuscitation for Hemodynamically Unstable Patients
- Establish two large-bore IV cannulae in anticubital fossae 1
- Infuse normal saline 1-2 liters initially to restore blood pressure and urine output >30 mL/hour 1
- Transfuse packed red blood cells when hemoglobin <100 g/L or with active bleeding and shock 1
- Correct coagulopathy with fresh frozen plasma if INR >1.5 3, 1
- Correct thrombocytopenia (<50,000/µL) with platelet transfusion 3
ICU Admission Criteria
Admit to intensive care unit if any of the following are present 3:
- Hematocrit decrease ≥6%
- Transfusion requirement >2 units packed red blood cells
- Continuous active bleeding
- Persistent hemodynamic instability despite aggressive resuscitation
Mandatory Physical Examination
Perform digital rectal examination on every patient to exclude anorectal pathology, confirm stool appearance, and detect palpable rectal masses—approximately 40% of rectal cancers are palpable 3, 1. Visual inspection must identify thrombosed external hemorrhoids, skin tags, prolapsed internal hemorrhoids, anal fissures, abscesses, or fistulas 4.
Critical Pitfall to Avoid
Never attribute all anorectal symptoms to hemorrhoids without proper examination—serious pathology including colorectal cancer may be missed 4, 5. Hemorrhoids are extremely common and may coexist with more serious pathology 4.
Diagnostic Approach Based on Age and Presentation
Patients Over 40-50 Years Old
All patients over 40 years presenting with rectal bleeding should undergo colonoscopy, as serious pathology is detected in 44.4% of cases, including colorectal cancer (8%), polyps ≥5mm (17%), and inflammatory bowel disease (11%) 2. The risk of colorectal cancer ranges from 2.4-11% in patients over 50 with rectal bleeding 1.
Colonoscopy should be performed urgently for major bleeds or within 2 weeks for minor bleeds, with diagnostic yield of 42-90% and allowing therapeutic intervention 1. In patients ≥70 years old, diverticulosis and angiodysplasia are the most common causes, accounting for up to 40% of cases 3.
High-Risk Features Requiring Urgent Colonoscopy
The cancer prevalence increases significantly with these features 6:
- Blood mixed with stool (not just on surface) 2
- Change in bowel habit: increases cancer prevalence to 9.2% 6
- Absence of perianal symptoms: increases cancer prevalence to 11.1% 6
- Palpable rectal mass: present in 36% of cancer patients 6
- Abdominal pain 2
- Anemia or guaiac-positive stools 4
Younger Patients (<40-50 Years)
Be aggressive in investigating younger patients because small bowel tumors are the most common cause of obscure bleeding in patients younger than 50 years 3. Inflammatory bowel disease (particularly ulcerative colitis) and Crohn's disease are leading causes in younger patients 3, 1, 7.
When Symptoms Are Unhelpful
Symptoms alone are unreliable for determining who requires investigation—symptoms changed significantly between initial GP consultation and colonoscopy in research studies 2. Over 96% of patients presenting with rectal bleeding do not have cancer, but the 3.4-11% who do require identification 6.
Alternative Diagnostic Modalities
For severe ongoing bleeding when colonoscopy is not diagnostic or feasible 1:
- Technetium-99m red blood cell scan
- CT angiography
- Catheter angiography with potential for therapeutic embolization
Special Circumstances Requiring Additional Workup
When Accompanied by Abdominal Pain
Urgent evaluation is required to consider inflammatory bowel disease, ischemic colitis, or complicated rectal prolapse with strangulation 1. Check inflammatory markers (C-reactive protein, procalcitonin, lactate) as these correlate with tissue necrosis and mortality 1. Perform urgent contrast-enhanced CT scan in hemodynamically stable patients to exclude perforation, ischemia, or obstruction 1.
Blood and Mucus Together
This combination is characteristic of ulcerative colitis and Crohn's disease, particularly when accompanied by watery diarrhea, cramping, urgency, or abdominal pain 4. All patients require sigmoidoscopy at minimum, regardless of whether hemorrhoids are visible 4.
History of Pelvic Radiation
Consider radiation proctitis, which may occur 9 months to 4 years after radiation therapy for prostatic or gynecologic malignancy 3.
Patients on Anticoagulation
Anticoagulant use does not preclude endoscopic intervention 3. For most hospitalized patients on warfarin with GI bleeding, reverse anticoagulation with fresh frozen plasma and vitamin K 3.
Endoscopy Safety Considerations
Elderly patients are at greater risk of complications (0.24-4.9%) compared to younger patients (0.03-0.13%) 3. Principal complications include hemorrhage, aspiration pneumonia, myocardial infarction, and bowel perforation 3.
Minimize risks through 3:
- Adequate resuscitation before the procedure
- Standard monitoring: heart rate, blood pressure, respiratory rate, oxygen saturation
- Continuous ECG monitoring for high-risk patients (history of dysrhythmia, cardiac dysfunction, elderly, extensive therapeutic procedures anticipated)
- Supplemental oxygen administration is mandatory, especially in patients with impaired pulmonary function