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PR Bleeding

Lower GI haemorrhage is classically bleeding from below the ligament of Trietz (the suspensory muscle of duodenum that connects to the diaphragm). Rarely, massive upper GI bleeding can also present with PR bleeding. Patients present with blood mixed in/with the stool or blood leaking from the rectum.

Here we will focus on patients presenting to hospital with acute, significant blood loss.

In general, the bleeding will stop spontaneously in 80-85% of patients, and the mortality rate is 2 to 4 percent. Massive lower GI bleeding usually occurs in patients >65 years who also have multiple medical problems. Link to diagram on severity of bleeding.


  • Diverticular disease – most common cause of significant bleeding

  • Haemorrhoids - most common cause of all cause bleeding

  • Angiodysplasia

  • Ischaemia

  • Neoplastic

  • Inflammatory – infectious/non infectious

  • Iatrogenic e.g. polypectomy.

Initial assessment, signs and symptoms

The patient’s history is important for accurate assessment of risk and can give important clues to the diagnosis and need for admission.

Age, co-morbidities and certain medications like aspirin increase the chance of significant haemorrhage.

Patients may present with:

  • Maroon stools, with bleeding from the right side of the colon

  • Bright red blood per rectum with bleeding from the left side of the colon

  • Melaena with caecal bleeding

  • Massive upper GI bleed can also present with bright red rectal bleeding

  • May or may not have abdominal pain.

Patients may present with signs of shock:

  • Assess for clinical evidence of hypovolemic shock (↑HR, ↓Pulse Pressure, ↓BP (beware compensation) ↑RR, ↑Cap refill, Cold clammy skin, ↓Urine Output, ↑Agitation /Confusion).

  • Mild / Moderate / Severe hypovolaemia is respectively indicated by resting tachycardia / Orthostatic Hypotension / Supine Hypotension and equates to approximately 15%, 30% and over 40% loss of total circulating blood volume (5L in 70kg male).


  • Must include PR

    • May identify source of bleeding e.g. haemorrhoids or feel a mass.

    • Haemorrhoids not always visible or palpable but finding of normal stool and no polyp/mass would suggest haemorroidal bleed or if painful PR, anal fissure.

    • Finding of frank blood / maroon stained blood mixed in with stool would suggest haemorrhoids not the cause, but rather diverticulosis (right sided) > angiodysplasia etc.

    • Consider PV exam to exclude PV bleeding masquerading as PR (especially in older patients)

  • Nasogastric tube insertion and aspirate to determine if upper GI bleed if suspected

Blood results:

  • Hb may be normal/low.


Bloods including FBC, EUC, LFT, coags, G&H/Xmatch.

ECG to look for myocardial ischaemia (especially in older patients and with comorbidities).

Colonoscopy – Most patients who present with rectal bleeding are investigated when stable. Urgent colonoscopy is only considered in actively bleeding and shocked patients. It should only be done once resuscitation has been optimised.

CT abdo with contrast/mesenteric angiogram – you may see:

  • Vascular extravasation of the contrast medium

  • Contrast enhancement of the bowel wall

  • Thickening of the bowel wall

  • Spontaneous hyperdensity of the peri-intestinal fat

  • Vascular dilatations

  • Neoplastic lesion

  • Diverticular disease.

Nuclear scintigraphy can be considered to assist in localising bleeding in patients with active recent haemorrhage.


  • Resuscitate patient – O2, IV fluids +/- blood

    • Shocked patients should receive fluid therapy to a MAP of 65 mmHg and red cells transfused after loss 30% circulating volume.

  • Monitoring - include stool chart for colour and volume.

  • Platelets may be required for those on antiplatelet agents. For information on massive blood ransfusion (i.e. needing platelets and FFP) click here.

  • Reverse bleeding disorders - ECI anticoagulation guide.

  • Colonoscopy with haemostatic techniques like clipping/adrenaline injections.

  • If bleeding continues significantly and resources available then embolization.

  • If above fails/not available the surgical intervention – laparotomy.


(Adapted from SIGN guidelines)

Consider for discharge with outpatient follow up if:

  • age <60

  • no evidence of haemodynamic compromise, and;

  • no evidence of gross rectal bleeding, and;

  • an obvious anorectal source of bleeding on rectal examination

Consider for admission if:

  • age ≥60 years, or;

  • haemodynamic disturbance, or;

  • evidence of gross rectal bleeding, or;

  • taking anticoagulation/antiplatelet agent.

For those admitted:

  • patients with continued brisk bleeding/haemodynamic instability/significant comorbidities should be admitted to ICU.

  • patients who are haemodynamically stable with minimal active bleeding are candidates for ward admission with close monitoring.

  • patients who undergo intervention should not come back to the ED and should go to the ward/ICU following the procedure.

Further References and Resources

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