Rectal bleeding

Lower gastrointestinal haemorrhage refers to bleeding from below the ligament of Treitz (a suspensory muscle that attaches the diaphragm to the duodenum).

Massive upper gastrointestinal bleeding can also present with rectal (PR) bleeding in rare cases. Patients present with blood mixed with the stool or blood leaking from the rectum.

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

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

Causes

• Diverticular disease, most common cause of significant bleeding
• Haemorrhoids, most common cause of all cause bleeding
• Angiodysplasia
• Ischaemia
• Neoplasm
• Inflammatory, infectious or non-infectious
• Iatrogenic, e.g. polypectomy

Initial assessment, signs and symptoms

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

Age, comorbidities 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 (note: massive upper gastrointestinal bleed can also present with bright red rectal bleeding)
• melaena with caecal bleeding
• may or may not have abdominal pain.

Patients may present with signs of shock.

• Assess for clinical evidence of hypovolemic shock (increased heart rate, decreased pulse pressure,  decreased blood pressure (beware compensation), increased respiration rate, increased capillary refill, cold clammy skin, decreased urine output, increased agitation or confusion).

Examination

Must include rectal examination:

• May identify the source of bleeding, such as a mass or haemorrhoids
• Haemorrhoids are not always visible or palpable. Finding normal stool and no polyp or mass suggests haemorrhoidal bleeding or, if painful PR, an anal fissure.
• Finding frank blood or maroon stained blood mixed in with stool suggests haemorrhoids are not the cause, but rather diverticulitis  (right sided), angiodysplasia, etc.

Blood results:

• Haemoglobin may be normal or low.

Investigations

Bloods including full blood count, electrolytes, urea and creatinine, liver function tests, a coagulation profile, and G&H/crossmatch.

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

Colonoscopy. Most patients presenting 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 of the abdomen with contrast or mesenteric angiogram. This may reveal:

• 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 help localise bleeding in patients with active recent haemorrhage.

Management

• Resuscitate the patient, oxygen, intravenous fluids with or without blood. Shocked patients should receive fluid therapy to a mean arterial pressure (MAP) of 65 mmHg and red cells transfused after loss 30% circulating volume.
• Monitor using a stool chart to record colour and volume.
• Platelets may be required for those on antiplatelet agents. Information on massive blood transfusion (i.e. needing platelets and fresh frozen plasma). See blood and blood products.
• Reverse bleeding disorders. See Anticoagulants (Clinical Excellence Commission).
• Colonoscopy with haemostatic techniques like clipping or adrenaline injections.
• Embolisation if bleeding continues significantly and resources available.
• If the above fail or are not available, then surgical intervention, laparotomy.

Disposition

Adapted from Scottish Intercollegiate Guidelines Network guidelines.

Consider for discharge with outpatient follow up if:

• age <60, and
• 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 or significant comorbidities should be admitted to ICU.
• patients who are haemodynamically stable with minimal active bleeding are candidates for ward admission with close monitoring.

Resources

• Cagir B, Ologun GO, Chico GF, et al. Lower gastrointestinal bleeding. Medscape; 26 Jul 2019.
• Raphaeli T, Menon R. Current treatment of lower gastrointestinal hemorrhage. Clin Colon Rectal Surg. 2012 Dec;25(4):219-27. DOI: 10.1055/s-0032-1329393.