Lower GI Bleeding | MRCEM EXPERT

Lower GI Bleeding Summary

Key Definition

Bleeding distal to ligament of Treitz
Presents with haematochezia
No gastric blood present

Common Causes

Diverticular disease (most common)
Angiodysplasia
Inflammatory bowel disease
Colorectal cancer
Hemorrhoids/anal fissures

Severe Bleeding Indicators

Systolic BP <115
HR >100
Syncope
Rectal bleeding in first 4h
≥2 comorbidities
Aspirin use

Investigations

Colonoscopy (first-line)
CT angiography
Radionuclide scan
EGD to rule out upper GI

Management

Resuscitation first
Colonoscopy within 24h
Angiography for massive bleeds
Surgery last resort

Discharge Criteria

Age <60 years
No hemodynamic disturbance
No gross rectal bleeding
No NSAIDs/anticoagulants

Definition

Lower GI bleeding is defined as bleeding distal to the ligament of Treitz (small bowel, colon, rectum) presenting with haematochezia (bright red blood per rectum) without gastric blood.

Causes

Common Causes

Diverticular disease (most common in elderly)
Angiodysplasia
Inflammatory bowel disease
Colorectal cancer
Infectious colitis
Hemorrhoids/anal fissures

Uncommon Causes

Meckel's diverticulum
Radiation telangiectasia
Aorto-enteric fistula
Vasculitis
Rectal varices
NSAID colopathy

Clinical Assessment

History

Age: >60 years suggests diverticular/angiodysplasia
Bleeding characteristics:
- Duration (acute/chronic)
- Blood color/mixing with stool
Associated symptoms:
- Syncope (significant blood loss)
- Abdominal pain/diarrhea (colitis)
- Weight loss/change in bowel habits (malignancy)
Risk factors: NSAID use, IBD, recent travel

Examination

Vital signs: Postural hypotension, shock index (HR/SBP ≥1)
Abdomen: Tenderness, masses, hepatomegaly
Rectal exam: Essential to exclude rectal mass

Severe bleeding indicators: Systolic BP <115, HR >100, syncope, rectal bleeding in first 4h, ≥2 comorbidities, aspirin use.

Investigations

Initial Tests

FBC: Hematocrit drop >6-8% indicates significant bleed
Coagulation screen: PT/APTT, platelets
Crossmatch: If active/severe bleeding
ESR/CRP: Elevated in IBD
Stool studies: Culture, O&P if diarrhea present

Further Investigations

Anoscopy

For suspected anorectal source (hemorrhoids)

Colonoscopy

First-line for diagnosis & therapy (within 24h for high-risk)

Radionuclide Scan

Detects slow bleeds (0.1mL/min)

CT Angiography

For persistent GI bleeding with negative colonoscopy or when endoscopy is not feasible

CT Abdomen

Useful for ischemic colitis and aortoenteric fistula. First test for suspected colonic ischemia

EGD

To rule out upper GI source. Also useful for aortoenteric fistula diagnosis

Serologic Markers

ANA, ANCA if vasculitic disease suspected (e.g., SLE)

Management

Resuscitation

Two large-bore IV lines
IV fluids to maintain perfusion
Blood transfusion if:
- Ongoing bleeding
- Hct drop >20%
- ≥2 units required
Correct coagulopathy (FFP, platelets)
ICU admission if unstable

Definitive Management

Colonoscopy

Therapeutic options:
- Thermal coagulation
- Epinephrine injection
- Hemoclips/banding
Risk of perforation

Angiography

For massive bleeds
Superselective embolization
Small ischemia risk

Surgery

Last resort
Segmental resection
Consider if >6 units transfused

Special Considerations

Anticoagulants: Reverse if INR >2.5 (vitamin K, PCC)
Diverticular bleed: 80% stop spontaneously
Hemorrhoids/fissures: Conservative management first

Discharge Criteria

Consider for discharge or non-admission with outpatient follow-up if:

Age <60 years; and
No evidence of haemodynamic disturbance; and
No evidence of gross rectal bleeding; and
Does not take NSAIDs or anticoagulants