The first thing when called is to identify whether the bleeding is truly a lower GI bleed or whether it is an Upper GI Bleed as the management differs. Both can quickly become emergencies so seek senior advice.

When the nurse first calls you
  • Check the observations & their trend (urgent review for haemodynamic instability)
  • If unwell, apply your A to E assessment (otherwise you can take a history as usual) 
  • If well with minimal PR bleeding, the focus is identifying who needs further testing & managing the underlying condition (see at the bottom)
Initial Assessment: The focus is circulation. If they are unwell or you're concerned:
  • Take bloods including a group & save (2 samples are needed if there's no historic sample)
  • A venous/arterial blood gas can give you an instant haemoglobin
  • Ideally 2 large cannulas, but a small cannula in a vein is better than a large one in the bin
  • Consider a major haemorrhage call as it is better to resuscitate with blood (& you might not have time to wait for properly matched blood)
  • Consider tranexamic acid (can cause clots)
  • Keep nil by mouth
Further emergency management
  • Lactate (tends to be elevated in colitis, very elevated in ischaemic colitis))
  • Bloods & stool samples
  • Imaging can be discussed with seniors (e.g. abdominal x-ray for features of colitis, erect CXR for perforation)
Causes of a large lower GI bleed
  • Colitis
    • Infectious (recent travel, gastroenteritis symptoms, very acute, exposure to antibiotics for c-difficile)
    • Inflammatory (chronic history of multiple episodes, family history, extra-intestinal associated features, nutritionally deplete)
    • Ischaemic (vascular risk factors)
  • Surgical
    • Post operative
    • Diverticulitis (known diverticular disease, constipation, associated pain, older)
    • Perforation (peritonism)
  • Blood thinners may exacerbate bleeding (and may need reversal e.g. warfarin)
Causes of small or minimal bright red blood per rectum
In this situation, you are reassured by minimal bleeding that is NOT mixed in with the stool because it is a lesion in the rectum or anal canal (and is more frequently benign). If it is mixed in consider colonic or small intestinal sources. 
  • Haemorrhoids
    • Painless bleeding associated with bowel movement. Bright red blood coats stool. Blood may be seen in toilet or on tissue
  • Anal fissures
    • Tearing pain with passage of stool, small amount of bright rectal on tissue or stool surface. Itch or perianal skin irritation
  • Polyps
    • Usually asymptomatic. Bleeding more likely with distal polyps
  • Proctitis
    • Intermittent rectal bleeding, mucus, and mild diarrhoea present in <4 small loose motions per day
  • Rectal cancers
    • bleeding, mucus, straining, sense of incomplete evacuation
  • Cancer
    • Haematochezia, abdominal pain, change in bowel habit, family history, weight loss, change in bowel habit. Likely lesion on left
Assessment & Investigations
Given the differential it is important to review red flags & consider whether a colonoscopy or sigmoidoscopy is necessary. 
  • If on examination (including a rectal examination) doesn't reveal the cause or there are red flags or they are older (especially above 50y) then colonscopy should be considered
  • In the intermediate population, a sigmoidoscopy could be offered first with a colonoscopy only if the cause was not identified. 
  • Beware though as there could be multiple pathologies - haemorrhoids are very common and the patient could have cancer also. 
Management of haemorrhoids & anal fissures
Due to their common nature, this is something you'll frequently need to provide some help with. Here's some things you could offer:
  • Fibre, water & laxatives as necessary aiming for soft stools
  • Regular exercise 
  • Any emollients/anaesthetic/anti-inflammatory agents you have at your hospital which can be used in the very short term (less than a week) for relief
Written by Dr Charlotte Knight
Edits by Dr Akash Doshi CT3