Article Text

Download PDFPDF

Guideline review
British Society of Gastroenterology: diagnosis and management of acute lower gastrointestinal bleeding
  1. Ashley Bond,
  2. Philip J Smith
  1. Department of Gastroenterology, Royal Liverpool and Broadgreen Hospitals NHS Trust, Liverpool, UK
  1. Correspondence to Dr Ashley Bond, Royal Liverpool and Broadgreen Hospitals NHS Trust, Liverpool L7 8XP, UK; ashleybond{at}


New guidelines have been produced through collaborative work between the British Society of Gastroenterology (BSG), the Association of Coloproctology of Great Britain and Ireland, the British Society of Interventional Radiology, the Royal College of Radiologists, National Health Service Blood and Transplants and patient representatives. This is the first UK national guidance for lower gastrointestinal bleeding (LGIB). The focus is the in-hospital management of adult patients presenting with acute LGIB. LGIB refers to patients presenting with bright or dark red blood per rectum, clots per rectum or blood mixed with stool. We provide a commentary and overview of the key features, with a particular focus on risk assessment, management, investigations, and radiological and endoscopic intervention.

  • gastrointestinal bleeding
View Full Text

Statistics from


Lower gastrointestinal bleeding (LGIB) has a reported incidence of 33–87/100 000 and can account for 3% of annual surgical referrals.1 2 LGIB represents a significant healthcare burden, with a UK in-hospital mortality of 3.4%, with this figure rising to 18% for those whose index event occurs as an inpatient. The majority of patients are admitted to general surgical wards, often with increasing age and a greater burden of comorbidity.3 In the UK, diverticular bleeding is the most common cause and is the most common indication leading to mesenteric embolisation. Despite the majority of patients being under the care of general surgeons, emergency laparotomy for bleeding is very uncommon.3 Overall, 23% of patients admitted to hospital with LGIB in the UK are discharged without a culprit lesion or diagnosis.3 The 2015 National Confidential Enquiry into Patient Outcome and Death (NCEPOD) report identified a number of deficiencies in the management. Notably, of the hospitals whom routinely admitted LGIB patients, only 55% were able to provide appropriate 24 hours a day/7 days a week (24/7) access to interventional radiology (IR) and 73% to 24/7 colonoscopy.4 The British Society of Gastroenterology has produced the guidance in response to this, and intended it to be used by all practitioners who are involved in the hospital care of patients with LGIB.

In this guidance, the term LGIB refers patients presenting with bright or dark red blood per rectum, clots per rectum or blood mixed with stool. Management of these patients is ideally led by gastroenterologists, who would be responsible for the emergency and ongoing care of all major GI bleeds.4

Key to the management is risk assessment, in particular, the ‘shock index’.4 This is calculated by dividing the heart rate by the systolic blood pressure and is a marker of active bleeding; thus, the need for more immediate intervention. Calculation of the shock index represents the first decision pivotal point in the management algorithm. A shock index of ≥1 is associated with an increased need for hospital-based intervention and increased mortality. It can also be used to predict contrast extravasation with CT angiography (CTA).

Patients presenting with LGIB and a shock index≥1 should undergo CTA (figure 1). As there is no clear evidence for the benefit of colonoscopy over CTA as the initial diagnostic procedure, CTA should be the preferred initial evaluation in patients who are unstable, owing to its speed of access, lack of need for bowel preparation and assessment of whole GI tract. If active bleeding is seen on CTA embolisation should be considered.

Figure 1

Flowchart summarising the initial assessment and subseuqent management of patients presenting with LGIB (adapted from associated BSG guideline).12 BP, blood pressure; BSG, British Society of Gastroenterology; IR, interventional radiology; LGIB, lower gastrointestinal bleeding.

The Royal College of Radiologists Standards of Practice recommends that IR teams should be in place within 60 min of the patient’s admission and 30 min of referral. If formal angiography is to be performed, this should occur as soon as possible after the positive CTA. When available on site, this should be possible within 60 min of the patients’ unstable presentation.5 Length of time between the performance of CTA and catheter angiography should act as a key performance indicator.

For patients with a shock index of less than 1 further risk assessment with the Oakland score is advised.6 This comprises seven routinely measured variables: age, gender, previous hospital admission with LGIB, digital rectal examination findings, heart rate, systolic blood pressure and haemoglobin level (table 1). Patients with a score of ≤8 have a 95% chance of safe discharged from the emergency department. Such patients can be offered urgent outpatient investigations with the subsequent timing judged on an individual basis; for example, within 2-weeks, as indicated by the National Institute of Clinical Excellence. A score of >8 is classified as a major bleed, indicating the patient is likely to benefit for hospital-based treatment.

Table 1

Variable comprising the Oakland score and the score attributed to each parameter

Colonoscopy is recommended as the preferred initial investigation for patients with major bleeding, in the absence of a shock index>1. The optimum time for colonoscopy for acute LGIB remains uncertain. A single randomised control trial (RCT) has directly compared colonoscopy at <12 hours and ‘delayed’ (30–60 hours). This study failed to demonstrate any significant difference in observed outcomes.7 A further observational study of 58 296 patients found that colonoscopy performed <24 hours from admission was associated with reduced length of stay and reduced transfusion requirements, but no difference on therapy requirements and mortality.8 As there is no clear evidence to support colonoscopy <24 hours, patients with major LGIB should have a colonoscopy performed on the next available list. Inpatient waiting time for colonoscopy should act as a key performance indicator. Patients should receive bowel preparation, preferably with polyethylene glycol-based solutions (eg, Moviprep), as these have been shown to perform best in the context of LGIB. In order to meet this requirement for an urgent colonoscopy, inpatient endoscopy provision may require emergency endoscopy slots.

In patients who are clinically stable but require blood transfusion, restrictive thresholds should be used, with a trigger to transfuse of <7 g/L. Aiming for a target of 7–9 g/L, taking care not to over-transfuse. This transfusion target may need to be increased when considering patients with ischaemic heart disease.

It has been reported that 11%–15% of patients presenting with LGIB actually have an upper GI source, meaning, therefore, >80% will not. Clinical indicators should be assessed that may suggest a brisk upper GI source for rectal bleeding. These include a history of peptic disease, portal hypertension and elevated urea/creatinine ratio. It is recommended that an upper GI endoscopy should be performed immediately if no source of bleeding is identified on the initial CTA in an unstable patient, that is, shock index>1.

For patients in whom initial CTA, lower GI and upper GI endoscopy are negative, nuclear imaging modalities and video capsule endoscopy (VCE) are the next line of investigation. There is little evidence to support the repeating of CTA or mesenteric angiography, unless there is further bleeding with haemodynamic compromise. Nuclear medicine imaging is of particular use when bleed rates are intermittent or slow. VCE is best performed as close as possible to the bleeding episode. If it is performed within 48 hours of the presentation of bleeding, the diagnostic yield is maximised, but may drop to below 50% if performed 72 hours after presentation.9

Surgery to control LGIB should be the last resort, with no patient proceeding to emergency laparotomy unless every effort has been made to localise the bleeding by radiological and/or endoscopic modalities, except under exceptional circumstances, for example, aortoenteric fistulae. In the UK, mortality from laparotomy is between 3.6% and 41.7%, with a varying consultant presence in theatre out of hours.10 Even if there has been a prior endoscopic or radiological investigation, it is advised to perform on-table endoscopy after induction of anaesthesia, before proceeding directly to surgery.

Tranexamic acid has been shown to improve mortality associated with major haemorrhage in trauma; however, its use in LGIB should remain confined to clinical trials pending the results of the haemorrhage alleviation with tranexamic acid-intestinal system (HALT-IT) trial.11

Anticoagulants and antiplatelet use are common in patients presenting with LGIB.3 Recommendations for each of these can be seen below, including consideration of restarting after bleeding resolution:

  • Warfarin—interruption of warfarin therapy at presentation is recommended. In cases of unstable bleeding, it should be reversed with prothrombin complex concentrate and vitamin K. For patients with low thrombotic risk, warfarin should be restarted at 7 days after haemorrhage. In patients with high thrombotic risk, low-molecular weight heparin therapy should be considered 48 hours after haemorrhage.

  • Aspirin—when being used for primary prevention, this should be immediately stopped and not restarted. For secondary prevention, it should not be routinely stopped. If stopped, if can be restarted once haemostasis has been achieved.

  • Dual antiplatelets (eg, aspirin and clopidogrel)—these should not be stopped in patients with coronary stents unless discussed with a cardiologist. It can be restarted at 5 days post haemorrhage.

  • Direct-acting oral anticoagulants (DOAC)—interrupting therapy at presentation is recommended, followed by discussed with haematology to consider specific reversal agents depending on the DOAC used. Restarting at a maximum of 7 days posthaemorrhage seems to be reasonable.

In 2015, NCEPOD recommended that patients with any acute GI bleed should only be admitted to hospitals with 24/7 access to on-site endoscopy, IR (on-site or covered by a formal network) on-site abdominal surgery, on-site critical care and anaesthetics. There is, therefore, a significant amount of service provision required in order to comply with these standards, with IR the most frequent deficit, followed by endoscopy.3

Key points

  1. Initial stratification according to shock index should be performed at presentation.

  2. Those with a shock index of >1 should have CT angiography (CTA) as the initial investigation of choice, followed by mesenteric angiography and embolisation if extravasation is present on CTA.

  3. For stable patients, the Oakland score should be calculated. Those with a score ≤8 should be considered for discharge from the emergency department. Those with a score >8 should be admitted and a colonoscopy performed on the next available list.

  4. Upper gastrointestinal (GI) endoscopy should be considered in an unstable patient (shock index>1) with a normal CTA, especially if the history of peptic disease, portal hypertension and elevated urea/creatinine ratio.

  5. Except in exceptional circumstances, surgery should only be considered when endoscopic and radiological options have been exhausted.

  6. A gastroenterologist should be the primary clinician responsible for the care of a patient with lower GI bleeding (LGIB).

  7. In order to adequately care for patients presenting with LGIB, the service must consist of 24 hours a day/7 days a week access to on-site endoscopy, IR (on-site or covered by a formal network) on-site abdominal surgery, on-site critical care and anaesthetics.


  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
  8. 8.
  9. 9.
  10. 10.
  11. 11.
  12. 12.
View Abstract


  • Collaborators AB and PJS reviewed the guidelines and drafted the manuscript jointly, reviewing all versions prior to submission.

  • Contributors AB and PJS produced the manuscript together and reviewed prior to submission.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Linked Articles

  • UpFront
    R Mark Beattie