What is the best management strategy for a patient with diverticulosis and a lower GI bleed?

Management of Diverticulosis with Lower GI Bleeding

For patients with diverticulosis and lower GI bleeding, immediate resuscitation with hemodynamic assessment using shock index (HR/systolic BP) determines the management pathway: hemodynamically unstable patients (shock index >1) require immediate CT angiography followed by transcatheter embolization, while stable patients should undergo urgent colonoscopy within 12-24 hours after rapid bowel preparation for both diagnosis and endoscopic hemostasis. 1, 2

Initial Resuscitation and Risk Stratification

Hemodynamic assessment is the critical first step:

• Calculate shock index (heart rate divided by systolic blood pressure) immediately—a value >1 indicates hemodynamic instability requiring aggressive intervention 2
• Transfuse red blood cells to maintain hemoglobin >7 g/dL (target 7-10 g/dL) in patients without cardiovascular disease, or >8 g/dL (target 10 g/dL) in those with cardiovascular disease 1, 2
• Maintain mean arterial pressure >65 mmHg while avoiding fluid overload 1
• Monitor hourly urine output targeting >30 mL/hour in severe cases 1

For stable patients, calculate the Oakland score (includes age, gender, previous lower GI bleeding admission, digital rectal examination findings, heart rate, systolic blood pressure, and hemoglobin level) to guide disposition 2:

• Oakland score ≤8 points: Safe for discharge with urgent outpatient colonoscopy within 2 weeks 2
• Oakland score >8 points: Admit for inpatient colonoscopy 2

Key prognostic context: Approximately 75% of diverticular bleeding episodes stop spontaneously, particularly in patients requiring <4 units of blood transfusion over 24 hours 1. However, mortality rises to 20% in patients requiring ≥4 units of red cells, though mortality is generally related to comorbidity rather than exsanguination 2.

Management Algorithm Based on Hemodynamic Status

For Hemodynamically Unstable Patients (Shock Index >1)

CT angiography (CTA) is the mandatory first diagnostic test—NOT colonoscopy—as it provides the fastest and least invasive means to localize bleeding before therapeutic intervention, with a 94% positive rate in unstable patients. 2

Following positive CTA, proceed immediately to catheter angiography with transcatheter embolization:

• Perform within 60 minutes in centers with 24/7 interventional radiology to maximize success rates 1, 2
• Use microcatheter for superselective embolization of single vasa recta at the bleeding site 1
• Technical success rates for embolization are 93-100% regardless of embolic agent used 1
• Recurrent bleeding and ischemic complications are less frequent when embolization is distal to a marginal artery with devascularized bowel length of only a few centimeters 1

Critical pitfall to avoid: Do not perform colonoscopy as the initial approach when shock index >1 or patients remain unstable after resuscitation—this delays definitive localization and treatment 2. Colonoscopy is explicitly contraindicated in this setting and should be reserved for stable patients or after successful localization and stabilization via angiography 2.

Surgery is reserved only for patients who fail angiographic intervention or continue to deteriorate despite all attempts at localization and intervention 2. Blind segmental resection and emergency subtotal colectomy are associated with substantial rebleeding rates (as high as 33%) and mortality (33-57%), so localization using CTA or angiography should always be attempted first 2.

For Hemodynamically Stable Patients

Urgent colonoscopy within 12-24 hours after hemodynamic stabilization is the recommended first-line approach:

• Administer rapid bowel preparation with 4-6 liters of polyethylene glycol solution over 3-4 hours before colonoscopy 1
• Use CO2 insufflation to reduce gas explosion risk in poorly prepared colons 1
• Perform colonoscopy on the next available inpatient list rather than emergently within 24 hours, as urgent colonoscopy (<24 hours) does not improve clinical outcomes including rebleeding, mortality, or length of stay 2

Endoscopic Treatment Options

When a bleeding diverticulum is identified, endoscopic hemostasis should be performed immediately as it significantly decreases early and late rebleeding rates:

• Endoscopic band ligation shows superior outcomes with lower early rebleeding rates (6%) compared to clipping (33%) 1
• Other therapeutic options include endoscopic clipping, injection therapy, thermal therapies, and hemostatic powders 1
• The presence of endoscopic stigmata such as visible vessel or adherent clot within a diverticulum reliably indicates severe hemorrhage requiring intervention 1

Angiographic Intervention for Failed Endoscopy

Consider angiography when endoscopic visualization or treatment fails, or when there is ongoing severe bleeding with hemodynamic instability:

• Angiography requires active bleeding at rates >0.5 mL/min to localize a bleeding site 1
• Transcatheter embolization should immediately follow arteriography when extravasation is identified 3, 1
• Embolization provides time to stabilize the patient and prepare the bowel, both of which contribute to better surgical outcomes if surgery ultimately becomes necessary 2

Surgical Management

Surgery is indicated for:

• Ongoing bleeding despite endoscopic and angiographic interventions 1
• Recurrent severe diverticular bleeding episodes 1
• Patients who remain unstable despite aggressive resuscitation AND after failure of other localization methods 2

When surgery is necessary:

• Segmental colectomy is preferred when the bleeding source is localized, with mortality rate of 5-10% and rebleeding rate of 14% at 1 year 1
• Avoid blind segmental resection—every effort should be made to localize bleeding through radiological and endoscopic modalities first 2

Anticoagulation and Antiplatelet Management

For patients on warfarin:

• Interrupt warfarin immediately at presentation 2
• For unstable hemorrhage, reverse with prothrombin complex concentrate AND vitamin K 2
• Restart warfarin at 7 days after hemorrhage for patients with low thrombotic risk 2

For patients on aspirin:

• Aspirin for primary prophylaxis should be permanently discontinued 2
• Aspirin for secondary prevention should not be routinely stopped; if stopped, restart as soon as hemostasis is achieved 2

Risk Factors for Rebleeding

Identify high-risk patients who require closer monitoring:

• History of prior diverticular bleeding 1
• Chronic kidney disease 1
• Failure to identify and treat bleeding point 1
• Initial heart rate >100/min, systolic blood pressure <115 mmHg, syncope, bleeding during first 4 hours of evaluation, aspirin use, and >2 active comorbidities predict severe bleeding requiring intervention 1

Organizational Requirements

Patients with diverticular bleeding should be admitted to hospitals with 24/7 access to endoscopy, interventional radiology, abdominal surgery, and critical care, as lack of interventional radiology access is independently associated with mortality. 1