What is the management for a lower gastrointestinal (GI) bleed caused by constipation?

Management of Lower GI Bleeding Secondary to Constipation

For lower GI bleeding caused by constipation (typically from anal fissures or hemorrhoids), initial management focuses on hemodynamic assessment, treating the underlying constipation with stool softeners and fiber supplementation, and addressing the bleeding source endoscopically if conservative measures fail. 1, 2

Initial Assessment and Stabilization

Assess hemodynamic status immediately using shock index (heart rate/systolic blood pressure), with a shock index >1 indicating instability requiring aggressive resuscitation. 2 Resuscitation should occur concurrently with initial evaluation, including fluid resuscitation and blood transfusion if necessary. 1

• Calculate the Oakland score for risk stratification in stable patients: scores ≤8 allow for outpatient management, while scores >8 require hospital admission. 1, 2
• Perform digital rectal examination to confirm blood in stool and identify anorectal pathology such as fissures or hemorrhoids, which are the most common causes of bleeding related to constipation. 2, 3
• Check for orthostatic hypotension, which indicates significant blood loss requiring ICU admission. 2

Diagnostic Approach

For Hemodynamically Stable Patients

Colonoscopy is the diagnostic procedure of choice with a diagnostic accuracy of 72-86% and should be performed within 24 hours after adequate bowel preparation. 1, 4 However, in the context of constipation-related bleeding:

• Consider sigmoidoscopy or anoscopy first if anorectal pathology (fissures, hemorrhoids) is strongly suspected based on history and physical examination, as these are the most common causes in constipation-related bleeding. 3
• Upper endoscopy should be performed if severe hematochezia with hypovolemia is present, as an upper GI source accounts for 10-15% of such cases. 1

For Hemodynamically Unstable Patients

CT angiography should be performed immediately as it provides the fastest means to localize bleeding, followed by catheter angiography with embolization within 60 minutes if CTA is positive. 2 Colonoscopy is explicitly contraindicated when shock index >1 or patients remain unstable after resuscitation. 2

Treatment of Constipation-Related Bleeding

Conservative Management

Address the underlying constipation immediately to prevent recurrent bleeding:

• Stool softeners (docusate) generally produce bowel movement in 12-72 hours. 5
• Fiber supplementation (psyllium) for relief of constipation, which typically produces bowel movement in 12-72 hours. 6
• Stop use and seek medical attention if constipation lasts >7 days, rectal bleeding occurs, or failure to have a bowel movement, as these may indicate a serious condition. 6

Endoscopic Intervention

Endoscopic hemostasis should be provided to patients with high-risk stigmata including active bleeding, non-bleeding visible vessel, or adherent clot. 4 Modalities include:

• Mechanical therapy, thermal coagulation, injection therapy, or combination approaches depending on the bleeding source, access, and endoscopist experience. 7, 4
• Repeat colonoscopy with hemostasis should be considered for patients with evidence of recurrent bleeding. 4

Management Algorithm

1. Assess hemodynamic stability using shock index and calculate Oakland score. 1, 2
2. For stable patients (shock index ≤1):
   • Perform digital rectal examination to identify anorectal causes. 2
   • Consider anoscopy/sigmoidoscopy if fissure or hemorrhoid suspected. 3
   • Perform colonoscopy within 24 hours if source not identified or if higher risk features present. 1, 4
   • Initiate stool softeners and fiber supplementation to treat underlying constipation. 6, 5
3. For unstable patients (shock index >1):
   • Immediate CT angiography followed by catheter angiography with embolization if positive. 2
   • Avoid colonoscopy until hemodynamically stable. 2
4. Correct coagulopathy with fresh frozen plasma (INR >1.5) or platelets (platelets <50,000/µL). 2
5. Consider repeat endoscopy if rebleeding occurs despite conservative management. 4

Common Pitfalls and Caveats

• Do not dismiss severe bleeding as "just hemorrhoids" without proper evaluation—10-15% of severe hematochezia originates from upper GI sources. 1
• Avoid performing colonoscopy in hemodynamically unstable patients (shock index >1), as this delays definitive intervention and increases mortality risk. 2
• Do not overlook the need to treat underlying constipation, as failure to address this will lead to recurrent bleeding from the same anorectal pathology. 6
• Mortality in lower GI bleeding relates more to comorbidity than exsanguination, with overall in-hospital mortality of 3.4% but rising to 20% in patients requiring ≥4 units of red cells. 2
• NSAIDs should be avoided in patients with history of lower GI bleeding to prevent recurrence. 4