Lower GI Haemorrhage

Lower GI bleeding originates below the ligament of Treitz. Common causes: diverticular disease, angiodysplasia, colorectal cancer, IBD, ischaemic colitis. Most stop spontaneously but haemodynamic instability requires urgent intervention.

Lower GI Bleed Pathway

The pathway

1 · Resuscitate

Two large-bore IV cannulas
Crystalloid resuscitation
Transfuse if Hb <70g/L (threshold <80 in older patients with comorbidities)
Target SBP >100

2 · Risk assessment

Oakland Score or NICE criteria: shock index (HR/SBP) >1 = high risk
Consider HDU if haemodynamically unstable

3 · Bloods

FBC, U&E, clotting, group & save/crossmatch
High urea:creatinine ratio (>100:1) suggests upper GI source

4 · Exclude upper GI source

If haematemesis, melaena, or haemodynamically compromised → upper GI bleed until proven otherwise. NG tube and gastroscopy.

5 · Colonoscopy

Bowel prep + colonoscopy within 24 hours if stable. Identifies source and allows treatment in 80–85% of cases.

6 · CT angiography

In active bleeding or haemodynamic instability. Identifies site for targeted IR embolisation.

7 · Anticoagulation review

Warfarin: hold and reverse (vitamin K ± prothrombin complex)
DOAC: hold; consider reversal if life-threatening

Drugs

Drug	Dose	Route	Notes
0.9% NaCl / Hartmann's	500ml	IV	Rapid bolus for haemodynamic support.
Vitamin K	5–10mg	IV/PO	Warfarin reversal. IV onset 6h.
Prothrombin complex	25–50 units/kg	IV	Emergency warfarin reversal.
Tranexamic acid	Not routinely indicated	—	Do NOT give routinely in acute GI bleeding — BSG/ACPGBI after HALT-IT: no mortality benefit, more VTE and seizures. Exceptional use is a consultant decision, documented as being without established benefit.

When to escalate

Haemodynamic instability not responding to resuscitation,Transfusion requirement >4 units,Rebleeding post-colonoscopy,IR embolisation or surgical intervention required

Reference: ACPGBI/BSG Lower GI Bleeding Guidelines 2019

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