What is the appropriate workup for a patient with hematochezia and which focused history questions should be asked for the history of present illness (HPI)?

Workup for Blood in Stool

Critical History Questions for HPI

Ask about the appearance and timing of blood to distinguish upper from lower GI sources and guide your diagnostic pathway. 1, 2

Essential Bleeding Characteristics

• Color and location of blood: Bright red blood on the surface versus mixed throughout stool versus melena (10-15% of hematochezia originates from upper GI tract despite bright red appearance) 3, 4, 2
• Volume and frequency: Scanty streaks versus large volume, single episode versus recurrent 1
• Relationship to bowel movement: Blood on toilet paper only, coating stool surface, or mixed throughout 1
• Presence of mucus: Blood with mucus suggests inflammatory bowel disease (ulcerative colitis, Crohn's disease) or infectious colitis 1

Associated Symptoms That Change Management

• Abdominal pain, cramping, urgency, or watery diarrhea: Suggests inflammatory or infectious colitis requiring stool studies 1
• Weight loss, change in bowel habits, or anemia symptoms: Red flags for malignancy requiring urgent colonoscopy 1, 4
• Fever or nocturnal bowel movements: Indicates inflammatory disease 1
• Pain with defecation: Suggests anal fissure 3, 1

Medication and Risk Factor History

• NSAIDs or anticoagulants: Increase bleeding risk and may indicate upper GI source 3, 4
• Age and family history: Colorectal cancer risk is 2.4-11% in patients with rectal bleeding; age >50 or family history mandates colonoscopy 1, 4
• History of portal hypertension, peptic ulcer disease, or angiodysplasia: Consider upper GI source 3

Diagnostic Workup Algorithm

Initial Assessment and Laboratory Testing

Perform digital rectal examination on every patient with blood in stool, but never assume hemorrhoids explain the bleeding without endoscopic evaluation. 3, 1

• Vital signs: Assess hemodynamic stability 3
• Complete blood count: Check hemoglobin and hematocrit to evaluate severity and detect anemia 3, 4
• Coagulation studies: PT/INR, PTT if on anticoagulation 4
• Blood type and crossmatch: If severe bleeding present 3

Physical Examination Priorities

• Digital rectal examination: Identify hemorrhoids, fissures, masses, or rectal trauma 3, 1
• Visual inspection: Look for thrombosed external hemorrhoids, skin tags, prolapsed internal hemorrhoids, anal fissure, abscess, or fistula 1
• Abdominal examination: Assess for tenderness, masses, or organomegaly 1

Endoscopic Evaluation: The Definitive Diagnostic Test

All patients with rectal bleeding require at minimum sigmoidoscopy, regardless of whether hemorrhoids are visible on examination. 1

When to Perform Upper Endoscopy First

• Severe hematochezia with hemodynamic instability: 10-15% have upper GI source 3, 4, 2
• History of peptic ulcer disease, portal hypertension, or angiodysplasia 3
• Nasogastric lavage showing blood, clots, or coffee grounds 3

Colonoscopy Indications (Diagnostic Yield 72-86%)

Colonoscopy is the procedure of choice for lower GI bleeding and should be performed after rapid bowel preparation. 3

• Mandatory for complete evaluation: Even when hemorrhoids are visible, as serious pathology may coexist 1, 4
• Atypical bleeding characteristics: Blood mixed throughout stool, not just on surface 1
• Presence of anemia or positive fecal occult blood test 1, 4
• Age >50 or colorectal cancer risk factors 1, 4
• Systemic symptoms: Weight loss, change in bowel habits 1

Anoscopy

• Perform as part of physical examination when feasible and well-tolerated 3
• Sigmoidoscopy alone is inadequate: Only diagnostic if actively bleeding lesion visualized 3

Additional Diagnostic Studies

Stool Studies

• Infectious workup: When fever or colitis symptoms present (diarrhea, cramping, urgency) 1
• Fecal occult blood testing: Useful for screening but hemorrhoids alone do not cause positive tests 2, 5

Imaging

• CT scan, MRI, or endoanal ultrasound: Only if suspicion of concomitant anorectal diseases (abscess, inflammatory bowel disease, neoplasm) 3, 1
• Not routinely indicated for uncomplicated hemorrhoids 3

Critical Pitfalls to Avoid

Never attribute all anorectal symptoms to hemorrhoids without proper endoscopic examination—colorectal cancer may be missed. 1, 2

• Hemorrhoids are extremely common and may coexist with more serious pathology 1, 4
• Anemia from hemorrhoidal disease is rare (0.5 per 100,000 population) 2
• Even resolved bleeding requires complete evaluation to identify the source and exclude malignancy 4, 2
• False-positive fecal occult blood tests can occur from hematuria contaminating toilet bowl samples 6