Rectal Bleeding in Adults

For details on rectal bleeding in children see separate article Rectal bleeding in children.

• Benign anorectal disease:
  • Haemorrhoids1
  • Anal fissure²
  • Fistula-in-ano
• Diverticular disease³
• Inflammatory bowel disease:⁴
  • Crohn's disease
  • Ulcerative colitis
• Neoplasia
• Coagulopathies
• Arteriovenous malformation

Less common causes of rectal bleeding

• Massive upper GI bleeding.
• Radiation proctitis.
• Ischaemic colitis (mesenteric vascular insufficiency).
• Solitary rectal ulcer syndrome.
• Dieulafoy's lesion of small or large bowel.
• Endometriosis.
• Meckel's diverticulum (in adults less often than children).
• Rectal varices.
• GI tract invasion of non-GI tract malignancy.
• Henoch-Schönlein purpura (children).
• Trauma (possible sexual abuse).

• The quantity and nature of bleeding:
  • Fresh bright red blood usually comes from low down in the GI tract. Examples include fissures and haemorrhoids.3
  • Remember bright red blood can also occur with pathology higher in the GI tract (for example, intussusception).
  • Blood mixed in with the stool has usually originated higher in the GI tract.
  • The quantity of blood is very difficult to assess from the history but it is important to get a description from the patient. Indirect measures of the severity of bleeding are essential (see classification, in 'Presentation', above).
• Abnormal weight loss should be identified. Even in infants, failure to thrive may help to identify the likely causes.
• Change in bowel habit (both frequency of defecation and consistency of stool) must be recognised.^5,6
• Tenesmus may be a feature (for example, with fissures).
• Anal symptoms, for example soreness, itching or prolapse, occur often with piles.
• Family history of bowel cancer or polyposis must be identified.
• Past medical history should be carefully documented with particular reference to causes of bleeding and GI tract pathology. Any history of trauma should not be overlooked.
• Medication history is important, as it may identify causes of bleeding (for example, warfarin and aspirin).

Examination

• General features. Look for:
  • Pallor or anaemia
  • Cardiovascular signs of shock, including tachycardia and hypotension (including orthostatic hypotension).
  • Cachexia or obvious weight loss.
  • Abdominal examination to identify, for example, masses and hepatomegaly.
• Stool examination or description:
  • Often possible on a home visit (is the motion still available to be seen?).
  • Blood mixed with stool: the blood is darker and this usually indicates a lesion on the left side of the colon or even transverse colon (often carcinoma or inflammatory bowel disease).
  • Shiny black- or plum-coloured stool is often not recognised by the patient as blood (melaena). This indicates bleeding from higher up the GI tract - these patients need admission for investigation (usually upper GI tract endoscopy), either immediately or through an upper GI tract bleeding fast-track service (see separate article Upper gastrointestinal bleeding (includes Rockall score)).
  • Occult faecal blood loss may be severe enough to cause iron-deficiency anaemia.
  • Bright red blood suggests a lesion in the rectum or anus. If blood is clearly separate from a stool, it indicates an anal lesion, usually haemorrhoids or a fissure - particularly if there are associated anal symptoms (for example, anal pain or pruritus ani) but, occasionally, other pathology (for example, proctitis or anal carcinoma). This emphasises the need for rectal examination.
  • With blood on the surface of the stool the lesion can be anal, but may be a more proximal lesion (for example, polyp or carcinoma in the rectum or descending colon).
• Rectal examination:
  • A digital rectal examination is usually appropriate, both to confirm blood in the rectum and to exclude any rectal or pelvic masses.
  • Proctoscopy and sigmoidoscopy should identify anorectal sources of bleeding.

• Benign anorectal disease:
  • Usually causes intermittent rectal bleeding.
  • Does not exclude more proximal causes of bleeding.
  • Rarely causes massive rectal bleeding but can do so with, for example, portal hypertension.
• Diverticulitis:
  • Is very common in the over-60s, being present in about half of patients. About 20% of such patients develop rectal bleeding.
  • Is most common in the sigmoid and descending colon and can therefore cause bright red rectal bleeding.
  • Causes bleeding which will stop spontaneously in 20% of patients. In 5% of cases the bleeding is massive.
• Colonic angiodysplasias:
  • Generally cause slow but repeated episodes of bleeding.
  • Are acquired lesions and more common in the over-60s.
  • The bleeding is often occult and sited on the right side of the colon and caecum.
  • Can present with iron deficiency anaemia.
• Inflammatory bowel disease:
  • Rarely causes massive GI bleeding.
  • Usually causes bloody diarrhoea when the cause is ulcerative colitis.7
  • Lower GI bleeding is less common with Crohn's disease compared with ulcerative colitis.⁸
• Adenocarcinoma of the colon and rectum:
  • These are common cancers.
  • Bleeding is usually occult and patients usually present with other signs and symptoms (for example, change of bowel habit or anaemia).
  • Is more common in older patients.

• Digital rectal examination, proctoscopy and sigmoidoscopy may be performed as part of the initial examination.9^,10
• Blood tests may be required:
  • FBC (and group and save if bleeding is profound or anaemia suspected).
  • Clotting studies may be appropriate.
  • Ferritin and iron studies if iron deficiency anaemia is suspected.
  • LFTs may be indicated if liver disease is suspected.
• Refer for sigmoidoscopy or colonoscopy where appropriate.¹⁰ Virtual colonoscopy may be an option.¹¹ (This method uses computed tomography (CT) to examine the prepared, distended colon. Interpretation of the data combines two dimensional methods with three-dimensional 'endoscopic fly-through' simulations, hence "virtual" colonoscopy.¹² The procedure does not require sedation, is well tolerated by patients and is relatively safe.)
  
  Guidance on urgency of referral is given below. Rapid access referral may be appropriate, and the patient may need immediate admission if bleeding is severe. Further investigations to identify the source of bleeding include:
  • Selective mesenteric angiography, which is particularly useful at identifying the point of bleeding. For rectal bleeding this is usually the inferior mesenteric artery (rather than superior mesenteric artery or coeliac axis).
  • Nuclear scintigraphic imaging (ten times more sensitive than mesenteric angiography).
  • CT scanning (helical used when routine work-up fails to detect cause of bleeding).
  • Double-contrast barium enema may be useful but should be avoided with acute bleeding, as it may make subsequent examination difficult.

Guidance for those assessing cases of rectal bleeding in hospital has also been produced.15 This is useful also for those considering referral.

• Follow-up in outpatients is suggested to be appropriate when:
  • The patient is less than age 60.
  • There is no haemodynamic disturbance.
  • There is no other evidence of massive rectal bleeding.
  • An obvious source of bleeding has been identified by rectal examination and/or sigmoidoscopy.
• Immediate admission is considered appropriate when:¹⁵
  • The patient is over the age of 60.
  • There is haemodynamic disturbance.
  • There is evidence of massive bleeding.
  • Aspirin, non-steroidal anti-inflammatory drugs (NSAIDS) or other drugs likely to exacerbate bleeding are being taken.
  • There is significant comorbidity.

1. Haemorrhoids, Prodigy (May 2008)
2. Anal fissure, Prodigy (May 2008)
3. Diverticular disease and diverticulitis, Prodigy (March 2008)
4. Guidelines for the management of inflammatory bowel disease in adults, British Society of Gastroenterology (2011)
5. Diarrhoea - adults assessment, Prodigy (December 2010)
6. Constipation, Prodigy (January 2008)
7. Ulcerative Colitis, Prodigy (June 2010)
8. Crohn's Disease, Prodigy (June 2010)
9. Rectal cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up, European Society for Medical Oncology (2010)
10. Primary colon cancer: ESMO Clinical Practice Guidelines for diagnosis, adjuvant treatment and follow-up, European Society for Medical Oncology (2010)
11. Computed tomographic colonography (virtual colonoscopy), NICE Interventional Procedure Guideline (2005)
12. Burling D, East JE, Taylor SA; Investigating rectal bleeding. BMJ. 2007 Dec 15;335(7632):1260-2.
13. Referral for suspected cancer, NICE Clinical Guideline (2005)
14. GI (lower) cancer - suspected, Prodigy (July 2005)
15. Management of acute upper and lower gastrointestinal bleeding, Scottish Intercollegiate Guidelines Network - SIGN (September 2008)

• Colorectal screening, Clinical Knowledge Summaries (January 2010)
• Colorectal cancer, NICE Clinical Guideline (November 2011)
• Diagnosis and management of colorectal cancer, Scottish Intercollegiate Guidelines Network (December 2011)