Synopsis
Stabilise acute haematochezia, recognise diverticular haemorrhage as a diagnosis requiring localisation and exclusion of alternatives, and coordinate endoscopic, radiological and antithrombotic decisions safely.
- Diverticular bleeding is often abrupt, painless and substantial because a vasa recta adjacent to a diverticulum ruptures; many episodes stop spontaneously but recurrence is important.
- Do not call bleeding diverticular simply because diverticula were seen previously. Cancer, angiodysplasia, ischaemic colitis, inflammatory disease, haemorrhoids and an upper-GI source need proportionate exclusion.
- Judge physiology before estimating colour or volume: calculate shock index, repeat observations, assess perfusion and establish venous access while history is taken.
- Haemoglobin can initially appear normal in acute blood loss, so serial values and clinical trajectory are more useful than a single reassuring result.
- For haemodynamic instability or suspected active major bleeding, BSG guidance prioritises CT angiography because it rapidly localises arterial extravasation and directs embolisation.
- A stable major lower-GI bleed generally requires admission and inpatient colonoscopy on the next available list after preparation; urgent unprepared colonoscopy is rarely effective.
- Transfuse red cells using the current restrictive NICE and local major-haemorrhage strategy, individualised for active exsanguination and cardiovascular ischaemia.
- Anticoagulant and antiplatelet interruption, reversal and restart must balance active haemostasis against the indication and thrombosis risk with the relevant specialist owner.
Key red flags
Abrupt painless passage of red or maroon blood, often with clots, in an older adult with diverticulosis is characteristic, but source attribution remains provisional until localisation or exclusion is adequate.
Syncope, tachycardia, hypotension, cool peripheries, oliguria, altered mentation or a shock index above the local instability threshold identifies high risk regardless of the initial haemoglobin.
Pain before blood, focal tenderness, fever or diarrhoea is atypical for uncomplicated diverticular haemorrhage and raises ischaemic colitis, infection, IBD or diverticulitis.
Melaena, haematemesis, raised urea relative to creatinine, liver disease, ulcer risk or haemodynamic instability with brisk haematochezia warrants parallel consideration of an upper source.
Investigation priorities
Classify haemodynamic instability and response to resuscitation before selecting the diagnostic route.
Management branches
Haematochezia accompanies shock, ongoing major loss or failure to respond durably to initial resuscitation.
- Begin ABCDE, two suitable venous lines, urgent bloods and crossmatch, warming, continuous observations and the local major-haemorrhage protocol when activation criteria are met.
- Call senior gastroenterology and colorectal teams, alert interventional radiology and transfusion services, and document last antithrombotic doses while analgesia and resuscitation continue.
- Arrange CT angiography promptly; if active extravasation is shown, proceed rapidly to catheter angiography and selective embolisation where available.
- If CTA is negative but instability continues, reassess for an upper source, intermittent bleeding and repeat or operative strategies through the multidisciplinary emergency team.
Bleeding is clinically major but haemodynamic stability is sustained after initial assessment.
- Admit, monitor stool and physiology, correct fluid and clinically important anaemia, and risk-assess comorbidity and antithrombotic indication.
- Undertake adequate bowel preparation with attention to aspiration, renal and fluid risks, then arrange colonoscopy on the next available appropriate list.