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.
2 min synopsisUK scopeSources checked 8 Sept 2026Clinical review pending
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Ongoing major lower gastrointestinal haemorrhage
Repeated large-volume haematochezia with a shock index above 1, syncope, organ hypoperfusion or continued transfusion need requires immediate resuscitation and rapid localisation.
Action: Activate the major-haemorrhage pathway when indicated, obtain large-bore access and blood-bank samples, correct coagulopathy appropriately, and arrange urgent CT angiography with gastroenterology, interventional radiology and surgical involvement.
Synopsis
Manage presumed diverticular haemorrhage as acute lower-GI bleeding: resuscitate, risk-stratify, localise active bleeding with appropriate imaging or endoscopy and avoid attributing the source without evidence.
Diverticular bleeding is classically abrupt, painless haematochezia from a vasa recta, but incidental diverticulosis does not prove the source.
Calculate shock index as heart rate divided by systolic blood pressure; a value above 1 indicates instability in the BSG lower-GI bleeding pathway.
After initial resuscitation, use CT angiography for suspected active bleeding or instability because it rapidly localises extravasation.
Key red flags
Heart rate divided by systolic blood pressure above 1 after initial resuscitation identifies haemodynamic instability and supports urgent CT angiography.
Haematochezia with shock can arise from a brisk upper gastrointestinal bleed, especially when CT angiography does not show a lower source.
New abdominal pain, fever or peritonism after arterial embolisation suggests colonic ischaemia and requires urgent reassessment.
Investigation priorities
01
ABCDE observations and blood bank samplesFirst step
identify shock and prepare blood support.
Management branches
Worked case: unstable arterial diverticular bleedUse shock index to localise and treat active loss
A 74-year-old passes repeated maroon stools while taking apixaban for atrial fibrillation. Pulse is 128/min and systolic blood pressure is 92 mmHg after initial fluid, giving a shock index of 1.39; admission haemoglobin is 98 g/L.
Continue ABCDE resuscitation, obtain two large-bore cannulas and crossmatch samples, assess organ perfusion and activate major-haemorrhage support according to ongoing loss rather than the first haemoglobin alone.
Interrupt apixaban, establish the last dose and renal function, and make any reversal decision with senior haematology guidance from bleeding severity and stroke risk.
Key medicines
Red blood cell transfusion in stable lower-GI bleedingIn a clinically stable patient who needs transfusion, use haemoglobin 70 g/L as the trigger and target 70–90 g/L; for a patient with cardiovascular disease use an 80 g/L trigger and 100 g/L target.Do not apply stable restrictive thresholds mechanically during active major haemorrhage or shock, when blood loss, perfusion, myocardial ischaemia, coagulopathy and the major-haemorrhage protocol determine replacement; reassess after each unit when feasible.
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 8 Sept 2026; clinical approval remains outstanding.