Initial Assessment and Management of Bleeding Per Rectum

Patient Evaluation

The American College of Emergency Physicians recommends beginning with immediate hemodynamic assessment, including vital signs and focused history, to determine bleeding severity and guide management 1, 2
Hemodynamic evaluation should include checking vital signs immediately to assess hemodynamic stability, including pulse rate, blood pressure, and signs of shock 2
Calculate shock index (heart rate/systolic BP); a shock index >1 indicates hemodynamic instability requiring urgent intervention 3

Obtain history of prior abdominal surgery, as it has 85% sensitivity for adhesive bowel obstruction if presenting with obstruction symptoms 4
Document medication use, particularly anticoagulants, antiplatelet agents, and NSAIDs 3
Assess for liver disease or portal hypertension history, as anorectal varices occur in up to 89% of patients with portal pressure >10 mmHg 5
Inquire about previous episodes of rectal bleeding, chronic constipation, unexplained weight loss, or recent trauma 2, 6

Perform digital rectal examination (DRE) to rule out other causes of lower gastrointestinal bleeding and assess for masses, hemorrhoids, fissures, or blood 1, 2
Examine for abdominal tenderness, distension, or peritoneal signs 4
Assess for signs of chronic liver disease if portal hypertension suspected 5

Complete blood count (CBC) with hemoglobin and hematocrit should be performed to assess severity of bleeding 1, 2
Coagulation studies, including PT/INR, aPTT, and platelet count, should be evaluated to assess coagulopathy 1, 3
Serum electrolytes, blood urea nitrogen (BUN), and creatinine should be assessed to evaluate metabolic status and renal function 2

Risk stratification scores incorporate vital signs and hemodynamic parameters, presence of blood at rectal examination, laboratory values, and comorbidities and anticoagulant/antiplatelet use 2

Anoscopy or proctosigmoidoscopy should be performed as first-line diagnostic tool when feasible and well-tolerated 1, 6
Flexible sigmoidoscopy or colonoscopy is recommended for all patients reporting rectal bleeding to adequately assess the source 6
Urgent colonoscopy within 24 hours is indicated for patients with high-risk features, evidence of ongoing bleeding, or hemodynamic instability 1

CT angiography (CTA) should be performed immediately in hemodynamically unstable patients with suspected ongoing bleeding before endoscopic or radiological therapy to locate the bleeding source 3
Contrast-enhanced CT scan is indicated if endoscopy fails to detect bleeding site or when endoscopic ultrasound is unavailable 1, 5
Imaging (CT, MRI, or endoanal ultrasound) should only be performed if there is suspicion of concomitant anorectal diseases 2, 6

Hemorrhoids are the most common benign cause, presenting as discrete radial bulging of anal cushions (not crossing dentate line) 2, 3
Anorectal varices appear as discrete, compressible, serpiginous submucosal veins crossing the dentate line in patients with portal hypertension 5, 3
Anal fissures can occur from trauma, including mechanical trauma from anal intercourse or douching 6
Rectal prolapse presents as circumferential full-thickness protrusion through the anus 7

Do not rely on initial hemoglobin values alone, as they may appear falsely normal in the first 30-60 minutes after acute bleeding; serial measurements are essential 8
Do not delay appropriate treatment for imaging in unstable patients; stabilization takes priority 7