What should be done for a patient experiencing rectal bleeding?

Management of Rectal Bleeding

For a patient with rectal bleeding, immediately assess hemodynamic status and perform digital rectal examination with anoscopy/proctoscopy as the first-line diagnostic approach, followed by colonoscopy within 24 hours for stable patients or CT angiography before endoscopy for unstable patients. 1, 2

Initial Assessment and Stabilization

Hemodynamic Evaluation

• Check vital signs immediately, including heart rate and blood pressure to calculate shock index (shock index <1 defines hemodynamic stability) 2
• Obtain complete blood count, hemoglobin/hematocrit, coagulation parameters, serum electrolytes, BUN, and creatinine 3, 2
• Perform blood typing and cross-matching if severe bleeding is present 3, 2

Risk Stratification

• Apply the Oakland score for risk stratification, which assigns points based on age, previous lower GI bleeding admission, blood on digital rectal exam, heart rate, systolic blood pressure, and hemoglobin level 2
• A score >8 classifies bleeding as major and mandates hospital admission 2

Diagnostic Algorithm Based on Hemodynamic Status

For Hemodynamically Stable Patients

• Perform digital rectal examination and anoscopy/proctoscopy first to identify common anorectal causes such as hemorrhoids or anal fissures 1, 2
• Proceed with colonoscopy within 24 hours after adequate bowel preparation, which has a diagnostic yield of 42-90% 2
• Examine the rectum with retroflexion (J-maneuver) during colonoscopy to evaluate hemorrhoidal disease and low rectal pathology 2

For Hemodynamically Unstable Patients

• Initiate immediate IV fluid resuscitation with crystalloids 3
• Transfuse packed red blood cells to maintain hemoglobin >7 g/dL 3, 1
• Perform CT angiography as the first-line investigation before endoscopy, with sensitivity of 79-95% and specificity of 95-100% for detecting active bleeding 1
• Avoid delaying CT angiography by attempting colonoscopy first in unstable patients 2

Specific Etiologies and Management

Anorectal Varices (Portal Hypertension-Related Bleeding)

If varices are suspected or identified:

Diagnostic approach:

• Use ano-proctoscopy or flexible sigmoidoscopy as first-line diagnostic tool 3, 4
• Perform urgent colonoscopy plus upper endoscopy within 24 hours if high-risk features or ongoing bleeding present 3, 4
• Consider endoscopic ultrasound with color Doppler as second-line tool for deep rectal varices 3, 4

Initial management:

• Involve hepatology specialists early in a multidisciplinary approach 3, 4
• For mild bleeding: provide IV fluid replacement, blood transfusion if necessary, correct coagulopathy, and optimize portal hypertension medications 3, 4
• For severe bleeding: maintain hemoglobin >7 g/dL and mean arterial pressure >65 mmHg while avoiding fluid overload 3, 4

Pharmacological therapy:

• Administer short course of prophylactic antibiotics (strong recommendation) 3, 4
• Consider vasoactive drugs (terlipressin or octreotide) to reduce splanchnic blood flow and portal pressure 3, 4
• Use non-selective beta-adrenergic blockers for prevention/prophylaxis of first and recurrent variceal bleeding, but temporarily suspend during acute bleeding 3, 4

Endoscopic interventions:

• Use local endoscopic procedures as first-line treatment where feasible: endoscopic variceal ligation, band ligation, sclerotherapy, or EUS-guided glue injection 3, 4

Advanced interventions if medical/endoscopic treatment fails:

• Embolization via interventional radiology for short-term bleeding control 3, 4
• Percutaneous TIPS to decompress portal venous system and reduce rebleeding risk if not contraindicated 3, 4
• Surgical procedures only when all other approaches fail 3, 4

Radiation-Induced Rectal Bleeding

If patient has history of pelvic radiation:

• Investigate with flexible endoscopy to determine bleeding cause 3
• Optimize bowel function and stool consistency to potentially reduce bleeding 3
• If bleeding does not affect quality of life (staining clothes, causing anemia, interfering with activities), reassure and observe 3
• If bleeding affects quality of life: stop/reduce anticoagulants if possible, and for severe bleeding start sucralfate enemas (2g suspension in 30-50ml water, twice daily, retained as long as possible) 3
• Consider definitive ablative treatment for telangiectasia, though evidence for long-term outcomes is scanty 3

Critical Considerations

Upper GI Source Exclusion

• Do not assume lower GI source without excluding upper GI bleeding: up to 15% of patients with serious hematochezia have an upper GI source 3, 1
• If colonoscopy is negative, perform upper endoscopy 1

Colorectal Cancer Risk

• The risk of colorectal cancer in patients with rectal bleeding ranges from 2.4-11% 3, 1
• Perform full colonoscopy if patient has risk factors for colorectal cancer or suspicion of more proximal bleeding source 3
• Approximately 6% of patients presenting with lower GI bleeding have underlying bowel cancer 2

Common Pitfalls to Avoid

• Never delay CT angiography in unstable patients by attempting colonoscopy first 2
• Do not discharge patients with Oakland score >8 without hospital admission and investigation 2
• Avoid fluid overload during resuscitation in variceal bleeding, as it may exacerbate portal pressure and increase rebleeding risk 3
• Do not rely on gastric lavage for diagnosis in suspected upper GI bleeding, as it does not provide reliable diagnosis or affect outcomes 1