What is the workup and treatment for bloody stools?

Workup and Treatment for Bloody Stools

Initial Assessment and Hemodynamic Stratification

The workup for bloody stools must begin with immediate assessment of hemodynamic stability, as this determines the entire diagnostic and therapeutic pathway. 1

Hemodynamic Status Determination

• Check vital signs immediately and calculate the shock index (heart rate divided by systolic blood pressure)—a value <1 defines hemodynamic stability 2
• Measure hemoglobin/hematocrit levels and assess coagulation parameters to evaluate bleeding severity 3, 1
• For severe bleeding, perform blood typing and cross-matching immediately 3, 1

Diagnostic Algorithm Based on Stability

For Hemodynamically UNSTABLE Patients (Shock Index ≥1):

Immediate surgery is indicated for patients with hemorrhagic shock non-responsive to resuscitation 3

• Begin IV fluid and blood product resuscitation to normalize blood pressure and heart rate 3
• Transfuse packed red blood cells to maintain hemoglobin above 7 g/dL (or 9 g/dL if massive bleeding, cardiovascular disease, or anticipated delay in intervention) 3
• Perform CT angiography (CTA) as the first-line investigation rather than endoscopy—CTA can detect bleeding at rates of 0.3 mL/min 1
• For patients with acute severe ulcerative colitis and life-threatening hemorrhage, subtotal colectomy with ileostomy is the surgical treatment of choice 3

For Hemodynamically STABLE Patients:

Begin with anoscopy/proctoscopy to identify common anorectal causes (hemorrhoids, fissures), followed by upper and lower GI endoscopy 1

Step-by-Step Diagnostic Sequence:

1. Perform anoscopy or proctoscopy first to rule out anorectal sources 3, 1
2. Proceed with sigmoidoscopy AND esophagogastroduodenoscopy (EGD) to exclude both lower and upper GI sources 3, 1
   • Upper GI sources can present with bright red rectal bleeding in cases of rapid transit 1
3. If initial endoscopy is negative and bleeding persists, perform contrast-enhanced CT scan before repeat colonoscopy 1
4. Consider nuclear medicine studies for intermittent or slow bleeding 1
5. Reserve angiography for active bleeding that cannot be localized by endoscopy 1

Special Clinical Contexts

Inflammatory Bowel Disease (IBD) Patients:

For patients with known or suspected IBD presenting with bloody stools ≥6 times daily plus tachycardia >90 bpm, fever >37.8°C, anemia (Hgb <10.5 g/dL), or ESR >30 mm/h, this defines acute severe colitis requiring urgent multidisciplinary evaluation 3

• If no improvement or deterioration within 48-72 hours of medical therapy, consider second-line therapy or surgery 3
• Approximately 66% respond to steroids; 34% require colectomy 3
• Indications for immediate surgery include: free perforation, life-threatening hemorrhage with hemodynamic instability, or generalized peritonitis 3

Neonatal/Infant Bloody Stools:

In neonates and infants, bloody stools are generally benign and self-limiting, with cow's milk protein allergy (CMPA) being the most common cause (53.3% of cases) 4

• Most affected infants (68%) are exclusively breastfed 5
• Cow's milk elimination diet does NOT affect the duration of rectal bleeding and should not be routinely implemented without confirmed allergy 5
• Only 1.7% require surgery (primarily for necrotizing enterocolitis stage III or volvulus) 4
• Colonoscopy in infants typically reveals focal mucosal erythema and aphthous ulcerations; viral particles on colonic epithelium are found in some cases 5

Medical Management

Resuscitation Targets:

• Maintain hemoglobin >7 g/dL (restrictive threshold); use 9 g/dL threshold for massive bleeding or cardiovascular comorbidities 3
• Normalize blood pressure and heart rate prior to endoscopic evaluation 3

Pharmacologic Considerations:

• For patients with IBD-related bleeding, dietary and lifestyle modifications (increased fiber and water intake) are first-line 3
• Flavonoids may be administered to relieve hemorrhoid-related symptoms 3
• Interrupt warfarin at presentation with GI bleeding 2

Surgical Indications

Surgery is indicated in the following scenarios:

1. Hemodynamic instability despite resuscitation 3
2. Free perforation or generalized peritonitis 3
3. Massive hemorrhage with increasing transfusion requirements 3
4. Acute severe ulcerative colitis non-responsive to medical therapy after 48-72 hours 3
5. Significant recurrent gastrointestinal bleeding 3

Surgical Approach:

• For acute severe ulcerative colitis with massive hemorrhage: subtotal colectomy with ileostomy 3
• For Crohn's disease: intraoperative ileoscopy can help localize bleeding source 3

Critical Pitfalls to Avoid

• Do not delay CTA in unstable patients—perform before endoscopy 1
• Do not assume upper GI sources are excluded based on bright red blood alone 1
• Do not delay surgery beyond 48-72 hours in acute severe colitis non-responsive to medical therapy, as mortality increases with perforation (27-57%) 3
• Do not routinely eliminate cow's milk in infants without confirmed allergy—this does not shorten bleeding duration 5
• Do not minimize melena significance—mortality for hospitalized patients with GI bleeding can reach 18% 2
• Approximately 20% of patients requiring ≥4 units transfusion have significant mortality risk 2