Lower GI bleed pathway

SJH Emergency Medicine
NHS Lothian

Acute lower GI bleed flowchart

Notes on the acute LGIB pathway

Please read the caveats at the side of the flowchart, reiterated and expanded:

  1. Acute lower GI bleed is defined as Fresh red blood or purple blood/clots per rectum
    1. DO NOT apply this protocol to patients with suspected IBD, suspected infective bloody diarrhoea, suspected brisk upper GI bleeding, suspected other aetiology
  2. Shock, as measured by shock index, is after adequate resuscitation (defined as after >1L fluid or 2 units of RCC)
  3. Shock index can be calculated on MDCalc [external link]
  4. Oakland score can also be calculated on MDCalc [external link]
  5. Patients who remain unstable should have critical care input for safe transfer and may require critical care admission
  6. Primary care can refer "non-shocked" lower GI bleeding patients direct to colorectal via SAU if felt to require admission (being mindful of note 1)
  7. If not shocked, and Oakland score >10 (i.e. bottom left part of pathway), admission to colorectal is dependent on "when aetiology agreed". This will likely precipitate CT angiograms outside the agreed pathway. These cases should be escalated early to a senior decision maker.

Notes on acute lower GI bleed

  1. Fresh red or purple blood +/- clots
  2. Majority due to haemorrhoids or diverticular disease
  3. >90% settle spontaneously
  4. CT abdomen angiogram (in unstable patients) defines ongoing bleeding / site
  5. I.R. & embolisation rarely required (<1%)
  6. Surgery rarely if ever required

Editorial Information

Last reviewed: 11/09/2025

Next review date: 11/09/2027

Author(s): NHSL Acute CMG.

Reviewer name(s): Deepankar Datta.

References
  1. NHS Lothian, "Acute lower GI bleeding pathway", updated August 2025, approved by NHSL acute CMG on 11th September 2025