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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Haematochezia and lower GI bleeding

Gastroenterology and hepatology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Escalate

Fresh or maroon rectal bleeding with shock, syncope, ongoing large-volume loss, severe abdominal pain, peritonism or rapidly changing physiology is an emergency. Start ABCDE, activate major-haemorrhage support when appropriate, obtain senior gastroenterology, colorectal, radiology and critical-care help, and remember that brisk upper gastrointestinal bleeding can present as haematochezia.

Synopsis

Stabilise lower gastrointestinal bleeding, distinguish minor self-limited bleeding from major or unstable haemorrhage, and sequence CT angiography, colonoscopy, embolisation and follow-up without assuming every fresh bleed is anorectal.

  • Classify unstable versus stable first; a shock index above one is a useful BSG warning, but beta-blockade, pacing and older age can conceal tachycardia.
  • Describe bright red, dark red or maroon blood, clots, mixing with stool, dripping, pain and melaena, but colour alone does not reliably locate a brisk bleed.
  • In unstable ongoing bleeding, CT angiography is the fastest widely available test to localise active haemorrhage and direct interventional radiology or surgery.
  • If CT angiography does not identify a lower source in an unstable patient, assess for upper gastrointestinal bleeding promptly because rapid upper bleeding may pass fresh.
  • Stable patients are stratified as major or minor with a validated tool such as the Oakland score plus clinical judgement; low score is not a discharge command.
  • A major stable bleed is admitted for colonoscopy on the next available list after preparation, while a minor self-terminating bleed may undergo urgent outpatient investigation when safe.
  • Diverticular bleeding is often painless and brisk, ischaemic colitis usually combines pain and blood, and anorectal disease commonly leaves blood on paper or surface; none is proven without adequate assessment.
  • Review anticoagulants, antiplatelets and NSAIDs immediately. Reversal, interruption and restart depend on bleeding severity and thrombotic indication and require named specialist ownership.
  • Rectal examination and proctoscopy can identify distal disease, but finding haemorrhoids does not explain anaemia, weight loss or a separate proximal cancer risk.

Key red flags

Unstable active haemorrhage

Ongoing large-volume blood with shock index above one, syncope, hypotension, cool peripheries, oliguria or raised lactate indicates major active bleeding and supports immediate resuscitation and CT angiography.

Ischaemic colitis

Abrupt cramping abdominal pain followed by bloody diarrhoea, often left sided and after hypotension or with vascular disease, raises colonic ischaemia. Peritonism, acidosis or right-sided disease increases concern for transmural injury.

Investigation priorities

01
Serial physiology and shock indexFirst step

Identify unstable bleeding and measure response to resuscitation before definitive localisation.

Management branches

Unstable bleedLocalise during resuscitation

Haematochezia continues with shock or a shock index above one.

  1. Begin ABCDE, obtain large-bore access, crossmatch, monitor urine output and activate local major-haemorrhage support according to physiology.
  2. Call gastroenterology, colorectal surgery and interventional radiology early and arrange CT angiography without allowing transport to interrupt resuscitation.
  3. If CTA shows active bleeding, proceed urgently to angiography and embolisation or the locally agreed definitive intervention.
  4. If CTA is negative but instability persists, investigate an upper source promptly and continue multidisciplinary reassessment rather than labelling the bleed resolved.
Stable bleedSeparate major from minor

The patient is haemodynamically stable after initial assessment.

  1. Calculate an Oakland score accurately and combine it with comorbidity, ongoing blood, haemoglobin, anticoagulation, examination and social reliability.
  2. Admit major bleeds for bowel preparation and colonoscopy on the next available list, with earlier escalation if physiology changes.
  3. Consider discharge only for a self-terminating minor bleed in a suitable low-risk patient, arranging urgent outpatient investigation and explicit return advice.

Key medicines

Agent-specific anticoagulant reversalFor life-threatening or uncontrolled bleeding, use the current local and BNF reversal regimen matched to warfarin, dabigatran, factor Xa inhibitor or heparin exposure.Reversal increases thrombosis risk and is not identical for each drug. Confirm last dose and renal function, involve haematology, and create a documented restart decision after bleeding control.
Intravenous crystalloid and blood componentsGive warmed crystalloid in limited reassessed boluses and blood components through the local major-haemorrhage or restrictive transfusion strategy according to active physiology.The first haemoglobin may be misleading. Avoid both under-resuscitation and unnecessary over-transfusion, monitor calcium and temperature during major transfusion, and individualise coronary and heart-failure risk.
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • BSG acute lower gastrointestinal bleeding guidelineShock index, Oakland stratification, CTA, colonoscopy, embolisation and antithrombotic management.
  • NICE NG12 suspected colorectal cancerFIT-supported investigation and referral for rectal bleeding and associated features.
  • NICE NG24 blood transfusionRestrictive transfusion, reassessment and blood-component practice outside major haemorrhage.
  • BSG endoscopy and antithrombotic guidelineBalancing bleeding, endoscopic intervention and thrombotic risk around antithrombotic medicines.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
Do not attribute bleeding to haemorrhoids without addressing anaemia, mass, bowel change and cancer risk.