Approach to a Patient with Lower Gastrointestinal Bleeding: A 1-Hour PowerPoint Presentation
Slide 1: Title Slide
Approach to Lower Gastrointestinal Bleeding A Systematic Evidence-Based Approach
Slide 2: Learning Objectives
By the end of this session, you will be able to:
- Rapidly assess hemodynamic stability using shock index and stratify risk using validated scoring systems 1
- Apply an algorithmic approach to diagnosis and management based on bleeding severity 2, 1
- Make evidence-based decisions regarding transfusion, anticoagulation reversal, and timing of interventions 1, 3
- Recognize critical pitfalls that increase mortality and morbidity 1, 4
Slide 3: The Critical First Question - Is This Really Lower GI Bleeding?
11-15% of patients presenting with brisk hematochezia and hemodynamic instability actually have an UPPER GI source 5
Red flags suggesting upper GI source:
- Hemodynamic instability (shock index >1) 5
- Elevated BUN/creatinine ratio 5
- Antiplatelet drug use 5
- Risk factors for peptic ulcer or portal hypertension 5
Action: Perform upper endoscopy FIRST if any red flags present 5
Slide 4: MCQ #1 (Difficult)
A 72-year-old man presents with bright red blood per rectum. HR 110, BP 95/60, Hb 8.2 g/dL. He takes aspirin for prior MI. His BUN is 45 mg/dL and creatinine 1.1 mg/dL. What is your FIRST diagnostic step?
A) Urgent colonoscopy
B) CT angiography
C) Upper endoscopy
D) Tagged RBC scan
E) Angiography with embolization
Answer: C - Upper endoscopy
Rationale: Despite hematochezia, this patient has multiple red flags for upper GI source: hemodynamic instability (shock index 1.16), antiplatelet use, and elevated BUN/Cr ratio. 11-15% of patients with brisk hematochezia have upper GI sources 5
Slide 5: Initial Assessment - The Shock Index
Calculate shock index IMMEDIATELY upon presentation: Heart Rate ÷ Systolic Blood Pressure 1, 5
Shock Index >1 = Hemodynamically UNSTABLE 1
- This single calculation dictates your entire management pathway 5
- Unstable patients bypass colonoscopy and go directly to CT angiography 1
Shock Index ≤1 = Hemodynamically STABLE 1
Slide 6: Risk Stratification - The Oakland Score
For hemodynamically STABLE patients (shock index ≤1), calculate Oakland score: 1, 3
Components:
- Age 1
- Gender 1
- Previous LGIB admission 1
- Digital rectal examination findings 1
- Heart rate 1
- Systolic blood pressure 1
- Hemoglobin level 1
Oakland Score ≤8: Safe for urgent OUTPATIENT investigation 1, 3
Oakland Score >8: Requires hospital ADMISSION for colonoscopy 1, 3
Slide 7: MCQ #2 (Difficult)
A 58-year-old woman with no prior GI bleeding presents with maroon stools. HR 88, BP 130/75, Hb 10.5 g/dL. Digital rectal exam shows maroon stool. Oakland score is 7. What is the most appropriate disposition?
A) ICU admission
B) Hospital admission for urgent colonoscopy
C) Discharge with outpatient colonoscopy within 24-48 hours
D) Observation unit for 6 hours then discharge
E) Emergency surgery consultation
Answer: C - Discharge with outpatient colonoscopy
Rationale: Shock index is 0.68 (stable), Oakland score ≤8 indicates safe discharge for urgent outpatient investigation 1, 3
Slide 8: The Four Categories of Lower GI Bleeding
Category 1 (75-90% of patients): Minor bleeding resolving with conservative therapy 2
- Manage with observation and colonoscopy 2
Category 2: Chronic intermittent bleeding 2
Category 3: Severe, life-threatening bleeding with hemodynamic stability between episodes 2
- Tc-99m RBC scans useful prior to angiography 2
- Urgent colonoscopy (with/without purge) may be diagnostic and therapeutic 2
Category 4: Continual active bleeding with hypotension 2
- Best served by urgent angiography or surgery 2
Slide 9: Resuscitation - The Restrictive Transfusion Strategy
For patients WITHOUT cardiovascular disease: 1, 3
For patients WITH cardiovascular disease: 1, 3
Critical point: Liberal transfusion worsens outcomes 5
Slide 10: Coagulopathy Correction - Act Immediately
INR >1.5: Transfuse fresh frozen plasma 2, 1, 4
Platelets <50,000/µL: Transfuse platelets 2, 1, 4
Patients on warfarin with UNSTABLE hemorrhage: 1
- Interrupt warfarin immediately 1, 3
- Give prothrombin complex concentrate (PCC) + IV vitamin K 1, 3
- If PCC unavailable, use fresh frozen plasma 3
Delays in correction worsen outcomes 5
Slide 11: MCQ #3 (Difficult)
A 68-year-old man on warfarin (INR 3.2) presents with massive hematochezia. HR 115, BP 85/55. What is the MOST appropriate immediate coagulopathy management?
A) Hold warfarin and observe
B) Vitamin K 10 mg IV only
C) Fresh frozen plasma 2 units
D) Prothrombin complex concentrate + IV vitamin K
E) Platelet transfusion
Answer: D - Prothrombin complex concentrate + IV vitamin K
Rationale: Unstable hemorrhage (shock index 1.35) on warfarin requires immediate reversal with PCC + vitamin K for fastest and most complete reversal 1, 3
Slide 12: Antiplatelet Management - A Nuanced Approach
Aspirin for PRIMARY prevention: Permanently discontinue 1, 4, 3
Aspirin for SECONDARY cardiovascular prevention: 1, 3
- Do NOT routinely stop 1, 3
- If stopped, restart as soon as hemostasis achieved (preferably within 5 days) 3
Dual antiplatelet therapy (aspirin + P2Y12 inhibitor): 3
- Continue aspirin 3
- P2Y12 inhibitor can be continued or temporarily interrupted based on bleeding severity and ischemic risk 3
- If interrupted, restart within 5 days 3
Slide 13: ICU Admission Criteria - Know These Cold
Admit to ICU if ANY of the following: 2, 1, 4
- Orthostatic hypotension 2, 1, 4
- Hematocrit decrease ≥6% 2, 1, 4
- Transfusion requirement >2 units packed RBCs 2, 1, 4
- Continuous active bleeding 2, 1, 4
- Persistent hemodynamic instability despite aggressive resuscitation 2, 1, 4
Slide 14: The Hemodynamically UNSTABLE Patient - A Different Algorithm
Shock index >1 = UNSTABLE 1
Step 1: Aggressive IV fluid resuscitation 5
Step 2: CT angiography (CTA) IMMEDIATELY - NOT colonoscopy 1, 5
Step 3: If CTA positive → Catheter angiography with embolization within 60 minutes 1
Step 4: If patient remains unstable despite all measures → Surgery 1
CRITICAL: British Society of Gastroenterology explicitly recommends AGAINST colonoscopy as initial approach when shock index >1 1
Slide 15: MCQ #4 (Difficult)
A 75-year-old man presents with ongoing bright red blood per rectum. HR 120, BP 80/50 despite 2L crystalloid. Hb 6.8 g/dL. Upper endoscopy negative. What is the NEXT step?
A) Urgent colonoscopy
B) CT angiography
C) Tagged RBC scan
D) Exploratory laparotomy
E) Observation with serial hematocrits
Answer: B - CT angiography
Rationale: Shock index 1.5 (unstable). CTA is first-line for unstable patients, NOT colonoscopy. CTA has 94% positive rate and guides subsequent catheter angiography/embolization 1, 5
Slide 16: The Hemodynamically STABLE Patient - Colonoscopy First
For stable patients (shock index ≤1) with Oakland score >8: 1
Colonoscopy is the primary diagnostic and therapeutic modality 1, 3, 6
Timing: Perform sometime during hospital stay 3
- No high-quality evidence that EARLY colonoscopy (within 24 hours) improves outcomes 3
- Allows time for adequate bowel preparation 3
Therapeutic options during colonoscopy: 6
Slide 17: The BLEED Classification - High-Risk Features
BLEED mnemonic identifies high-risk patients: 2, 5
- Bleeding (ongoing) 2
- Low systolic blood pressure 2
- Elevated prothrombin time 2
- Erratic mental status 2
- Disease (unstable comorbid) 2
Additional high-risk features: 2, 5
- Heart rate >100/min 2, 5
- Syncope 2, 5
- Nontender abdomen 2, 5
- Bleeding per rectum during first 4 hours 2, 5
- Aspirin use 2, 5
- More than two active comorbidities 2, 5
Slide 18: MCQ #5 (Difficult)
A 82-year-old woman with dementia, atrial fibrillation on warfarin (INR 2.8), and CHF presents with hematochezia. HR 105, BP 110/70, confused (baseline alert). Which BLEED criteria are present?
A) 2 criteria
B) 3 criteria
C) 4 criteria
D) 5 criteria
E) 1 criterion
Answer: C - 4 criteria
Rationale: Bleeding (ongoing), Elevated PT (INR 2.8), Erratic mental status (confused), Disease (unstable comorbid - CHF, AF). Low BP not present (110/70) 2
Slide 19: Common Etiologies and Their Natural History
Diverticular bleeding (most common): 2
- Resolves spontaneously in >75% of patients 2
- Majority require <4 units transfused blood 2
- Recurrence: 14-38% after primary episode 2
- Long-term recurrence: 9% at 1 year, 25% at 4 years 2
Angiodysplasia: More common in patients >70 years 2
Other causes: 6
Slide 20: Mortality Context - What Really Kills These Patients
Overall in-hospital mortality: 3.4% 1, 5
BUT mortality rises dramatically in specific scenarios: 1, 5
- 18-23.1% for inpatient-onset bleeding (bleeding during hospitalization for other reasons) 2, 1
- 20% for patients requiring ≥4 units of red cells 1, 5
Critical insight: Mortality relates to COMORBIDITY, not exsanguination 1, 5
- Lower GI bleeding per se is uncommonly the cause of death 2
Slide 21: When Colonoscopy Fails - Next Steps
If colonoscopy unsuccessful or cannot be performed: 6
For active bleeding: Angiography 6
- Allows both diagnosis and therapeutic embolization 6, 7
- Modern techniques: non-selective cone-beam CT arteriography identifies damaged vessels faster 7
- Preferred embolic agents: detachable coils or liquid embolics 7
For intermittent bleeding: 2, 6
- Tc-99m RBC scan (reserved for unexplained intermittent bleeding when other methods fail) 2, 6
- Video capsule endoscopy for small bowel sources 8
Slide 22: MCQ #6 (Difficult)
A 65-year-old man undergoes colonoscopy for ongoing LGIB (stable hemodynamics). No source identified despite adequate prep. He continues to have intermittent maroon stools every 2-3 days. What is the MOST appropriate next diagnostic step?
A) Repeat colonoscopy
B) Angiography
C) Tagged RBC scan
D) Exploratory laparotomy
E) CT angiography
Answer: C - Tagged RBC scan
Rationale: For intermittent bleeding when colonoscopy fails, Tc-99m RBC scan is appropriate. Angiography limited for slow, sporadic bleeding. RBC scan can detect bleeding rates as low as 0.1 mL/min and guide subsequent angiography 2, 6
Slide 23: Surgery - The Last Resort
Surgery indicated when: 1
- Active bleeding from segmental lesion amenable to surgical cure 1
- Failure of angiographic intervention 1
- Patient continues to deteriorate despite all localization/intervention attempts 1
CRITICAL: Blind segmental resection has terrible outcomes: 1
Modern approach: Localization FIRST (CTA or angiography), then targeted resection 1
Slide 24: Critical Pitfalls to Avoid
Pitfall #1: Assuming hematochezia = lower GI source 5
- 11-15% have upper GI source - always consider upper endoscopy first if unstable 5
Pitfall #2: Performing colonoscopy on unstable patients 1
- Shock index >1 → CTA first, NOT colonoscopy 1
Pitfall #3: Liberal transfusion strategy 5
- Worsens outcomes - use restrictive thresholds 5
Pitfall #4: Delaying coagulopathy correction 5
- Delays worsen outcomes - correct immediately 5
Pitfall #5: Blind surgical resection without localization 1
- 33-57% mortality - always attempt localization first 1
Slide 25: The Complete Algorithm - Putting It All Together
STEP 1: Calculate shock index (HR/SBP) 1
If shock index >1 (UNSTABLE):
- Aggressive resuscitation 5
- Correct coagulopathy immediately 5
- Upper endoscopy if red flags present 5
- CT angiography → catheter angiography/embolization 1
- Surgery if all else fails 1
If shock index ≤1 (STABLE):
- Calculate Oakland score 1
- Oakland ≤8: discharge for outpatient colonoscopy 1
- Oakland >8: admit for colonoscopy 1
- If colonoscopy fails: angiography or RBC scan based on bleeding pattern 2, 6
Slide 26: MCQ #7 (Difficult)
A 70-year-old man with diverticulosis presents with his third episode of LGIB in 2 years. Each episode resolved spontaneously. He is currently stable (shock index 0.7) with maroon stools. What is his approximate risk of rebleeding over the next 4 years?
A) 5%
B) 10%
C) 25%
D) 50%
E) 75%
Answer: C - 25%
Rationale: For diverticular bleeding managed conservatively without definitive therapy, recurrence rates are 9% at 1 year, 10% at 2 years, 19% at 3 years, and 25% at 4 years 2
Slide 27: Special Consideration - Anticoagulation Resumption
For patients on warfarin: 1
- Low thrombotic risk: Restart warfarin 7 days after hemorrhage 1
- High thrombotic risk: Individualize timing with cardiology/hematology 1
For patients on direct oral anticoagulants (DOACs): 3
For patients on aspirin (secondary prevention): 3
- Restart as soon as hemostasis achieved, preferably within 5 days 3
Slide 28: MCQ #8 (Difficult)
A 78-year-old woman with mechanical aortic valve on warfarin presents with LGIB requiring 3 units PRBCs. Colonoscopy shows diverticular bleeding, successfully treated with clips. She is now stable. When should warfarin be restarted?
A) Immediately
B) 3 days
C) 7 days
D) 14 days
E) Never - switch to DOAC
Answer: B - 3 days (or sooner with cardiology consultation)
Rationale: Mechanical valve = HIGH thrombotic risk. While guideline suggests 7 days for low-risk patients, high-risk patients require earlier resumption. Hemostasis achieved, so can restart sooner than 7 days with specialist input. Never switch mechanical valve patients to DOACs (contraindicated) 1
Slide 29: The Digital Rectal Examination - Don't Skip It
Always perform digital rectal examination: 2, 1
Provides critical information:
- Confirms blood in stool 1, 4
- Characterizes bleeding (melena vs. hematochezia) 4
- Excludes anorectal pathology 2
- Approximately 40% of rectal carcinomas are palpable 2
Part of Oakland score calculation 1
Slide 30: Key Historical Features to Elicit
Age: Diverticula and angiodysplasia more likely >70 years 2
Medications: 2
Past medical history: 2
- Prior pelvic radiation (radiation proctitis 9 months to 4 years later) 2
- Coronary artery disease (affects transfusion threshold) 1, 3
- Cirrhosis 2
- COPD 2
Associated symptoms: 2
- Abdominal pain, weight loss, fever, diarrhea suggest inflammatory/infectious/malignant lesions 2
Slide 31: MCQ #9 (Difficult)
A 55-year-old man with prostate cancer treated with pelvic radiation 18 months ago presents with intermittent bright red blood per rectum for 2 weeks. Hemodynamically stable. What is the MOST likely diagnosis?
A) Diverticular bleeding
B) Angiodysplasia
C) Radiation proctitis
D) Colon cancer
E) Hemorrhoids
Answer: C - Radiation proctitis
Rationale: Radiation proctitis occurs 9 months to 4 years after pelvic radiation therapy. Timing (18 months) and history of pelvic radiation make this most likely 2
Slide 32: Modern Imaging Advances
CT angiography advantages: 1
- Fastest, least invasive localization 1
- 94% positive rate in unstable patients 1, 4
- Guides subsequent therapy 1
Cone-beam CT arteriography: 7
- Identifies damaged vessels during angiography 7
- Facilitates direct microcatheter placement 7
- Reduces time to embolization 7
Video capsule endoscopy: 8
Slide 33: Embolization Techniques
Preferred embolic agents: 7
- Detachable coils (with or without triaxial system) 7
- Liquid embolics 7
- Proven advantages over other agents 7
Success factors: 7
- Time to intervention (faster = better outcomes) 7
- Precise vessel identification 7
- Appropriate embolic agent selection 7
Angiography-directed surgery outcomes: 2
Slide 34: MCQ #10 (Difficult)
A 68-year-old woman undergoes CTA for unstable LGIB, showing active extravasation in the sigmoid colon. Catheter angiography confirms bleeding from sigmoid branch. What is the MOST appropriate embolic agent?
A) Gelfoam
B) Detachable coils
C) Polyvinyl alcohol particles
D) Absolute ethanol
E) No embolization - proceed to surgery
Answer: B - Detachable coils
Rationale: Detachable coils (with or without triaxial system) and liquid embolics have proven advantages over other embolic agents for LGIB 7
Slide 35: Multidisciplinary Approach
Lower GI bleeding requires collaboration among: 8
Transfer to specialized center if: 8
- Minimally invasive techniques unavailable locally 8
- Patient stabilized but requires advanced intervention 8
Complexity and diversity of LGIB demand team-based care 8
Slide 36: Take-Home Messages
1. Calculate shock index FIRST - it dictates everything 1, 5
2. Shock index >1 → CTA, NOT colonoscopy 1
3. Don't assume hematochezia = lower GI source (11-15% are upper GI) 5
4. Use restrictive transfusion thresholds (Hb 7 g/dL for most, 8 g/dL for cardiac disease) 1, 3
5. Correct coagulopathy immediately - delays worsen outcomes 5
6. Oakland score ≤8 in stable patients = safe discharge 1, 3
7. Mortality relates to comorbidity, not exsanguination 1, 5
8. Never perform blind surgical resection - localize first 1
9. Stop aspirin for primary prevention; continue for secondary prevention 1, 3
10. Most LGIB (75-90%) stops spontaneously, but high-risk features demand aggressive intervention 2, 5