Rectal Bleeding

The passage of blood per rectum is a very common symptom. It is often attributed by patients to 'piles' and indeed haemorrhoids or 'piles' are a common cause of this symptom. However, there are other causes and it is important to know what the possible causes are and when and how to investigate this symptom further. The type and amount of the bleeding as well as the age of the patient are important in initial assessment of the bleeding. There are many causes of rectal bleeding and the likely aetiology depends on the age of the patient and the frequency of the underlying diseases in a given population. Rectal bleeding always warrants further assessment and medical advice. It is essential to make appropriate referrals, which means that referrals should be made when necessary to the right specialist team with the correct degree of urgency.

The pattern of disease and modes of investigation have changed over the last 100 years. Early in the 20th century tumours of the large bowel were the most common cause of lower gastrointestinal bleeding. About 50 years ago diverticulitis became the most common cause of lower gastrointestinal bleeding. In the 1960s and 1970s selective mesenteric angiography permitted identification of angiodysplasia as a common cause of bleeding. The full length flexible sigmoidoscope was developed in 1965 in Japan and this technique has improved both diagnostic accuracy and therapeutic possibilities.

• The incidence of rectal bleeding is essentially unknown.
• Empirically it is a very common symptom, particularly in general practice. Few patients with rectal bleeding require hospital admission.
• The incidence rises with age (about 200 times between the third and ninth decades of life) as does the likelihood of hospital admission for lower gastrointestinal haemorrhage.
• In Western societies diverticulosis is common and hence it is a common cause of rectal bleeding.

It is difficult to get accurate figures for the relative frequency of the different causes of rectal bleeding. Different studies have different results according to population differences, patient selection, size of study and other confounding factors. However it is essential to understand the aetiology as this shapes the investigations, management and ultimately the likely outcome. As well as common causes it is important to remember rare causes. Occasionally bright red blood appears rectally from massive haemorrhage high up in the gastrointestinal tract. In as many as 20% of patients no cause can be identified even when there has been considerable blood loss.

Adults

• 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 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:¹
  • Rarely causes massive gastrointestinal bleeding.
  • Usually causes bloody diarrhoea when the cause is ulcerative colitis.²
  • Lower gastrointestinal bleeding is less common with Crohn's disease compared with ulcerative colitis.³
• 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 habit⁴ or anaemia).
  • Is more common in the older patients.

Children

The likely causes are different in children and vary according to the age of the child, as can be seen from the table above. For example:

• Anal fissures:
  • Occur in neonates and infants but also in older children.
  • Bright blood and pain are features of this condition.
• Necrotising enterocolitis:
  • Occurs in neonates.
  • Recurrent bleeding in an infant recovering from this condition may indicate recurrence or stricture.
• Volvulus:
  • Can occur in neonates and infants.
  • In neonates it is heralded by sudden onset of melena and bilious vomiting.
  • In infants volvulus can also occur and presenting features include vomiting and abdominal distension.
  • Rectal bleeding occurs relatively late with development of gangrenous bowel.
• Intussusception:
  • Occurs most often between 6 and 18 months.
  • Pain, distension, vomiting and a sausage shaped mass are characteristic as is the passage of blood and mucous in the form of redcurrant jelly stool.
• Milk protein allergy:
  • Can cause occult or overt rectal bleeding.
  • It is also associated with diarrhoea, weight loss, vomiting and general irritability.
  • Symptoms resolve when the offending milk product is withdrawn.
• Polyps:
  • Generally cause painless recurrent bleeding.
  • In infants and up to teenage years they are most often juvenile polyps which autoamputate and usually require no treatment.
  • Other polyposis syndromes are diagnosed at colonoscopy.
• Meckel's diverticulum:
  • Occurs in about 2% of the population (2 feet from the caecum and 2 inches in length) and commonly presents before age 4 years often with quite brisk rectal bleeding.
  • It is a remnant of the vitello-intestinal duct and apart from bleeding can present in a variety of other ways or remain symptomless.
  • Can also cause melaena at about age 10 years.
• Inflammatory bowel disease (IBD):
  • Starts to become more common over age 2 years.
  • Bleeding occurs less often with Crohn's disease than with ulcerative colitis, but both can cause bloody diarrhoea.
  • Rectal bleeding usually occurs in children known to have IBD rather than as a presenting feature of the IBD.
• Infectious diarrhoea:
  • Includes that caused by C. difficile and causes bleeding associated with profuse diarrhoea.
  • Gastroenteritis in many varieties (more commonly Campylobacter)
• Vascular lesions:
  • Includes a range of haemangiomas, arteriovenous malformations and malformations which can be difficult to detect even with new techniques.
  • Colonoscopy and arteriography are used to localise bleeding.

In assessing rectal bleeding it is important to identify important presenting features as these can give clues to the likely aetiology and severity of bleeding. It is for example important to assess the amount of bleeding. There are 3 classifications according to the amount of bleeding:

• Occult bleeding:
  • Can occur at any age
  • Can present with anaemia
  • Many possible causes
• Moderate bleeding:
  • Can occur at any age
  • May present with rectal bleeding (fresh or dark, even melena)
  • Haemodynamically stable
  • Many possible causes
• Massive bleeding:
  • Usually elderly
  • High mortality
  • Most commonly caused by diverticulitis and angiodysplasia
  • See box below

Massive lower gastrointestinal bleeding requires urgent admission.

Symptoms

Important features include:

• The quantity and nature of bleeding:
  • Fresh bright blood usually comes from low down in the gastrointestinal tract (GIT). Examples include fissures and haemorrhoids.
  • Remember bright blood can also occur with pathology higher in the GIT (for example intussusception).
  • Blood mixed in with the stool has usually originated higher in the GIT.
  • 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 above).
• Abnormal weight loss should be identified. Even in infants failure to thrive may help identify the likely causes.
• Change in bowel habit (both frequency of defaecation and consistency of stool) must be recognised.
• 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 GIT 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 GIT endoscopy), either immediately through an upper GIT bleeding fast track service (see Upper GI Bleeding).
  • Occult faecal blood loss may be severe enough to cause iron deficiency anaemia, which may only show up on faecal occult blood testing.
  • Bright red blood suggests a lesion in rectum or anus. If blood clearly separate from stool indicates an anal lesion, usually haemorrhoids or fissure (particularly if there are associated anal symptoms for example anal pain or pruritis 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 rectum or descending colon).
• Rectal examination:
  • A digital rectal exam is usually appropriate both to confirm blood in rectum and to exclude any rectal or pelvic masses.
  • Proctoscopy and sigmoidoscopy should identify anorectal sources of bleeding.

Patients with rectal bleeding can have bled from anywhere in the GIT and there are many possible causes. The likely causes can be appreciated from the aetiology (above) and are different in different age groups and different populations.

The investigations chosen will depend on the particular mode of presentation and likely diagnosis. It is important that unnecessary investigation does not delay referral.⁵ Rectal examination and full blood count are worth performing on all patients prior to referral.⁵

• Digital rectal exam and proctoscopy and even sigmoidoscopy^6,7,8 may have been performed as part of the initial examination.
• Bloods may be required:
  • FBC (and group and save if bleeding profound or anaemia suspected)
  • Clotting studies may be appropriate
  • Liver function tests may be indicated if liver disease is suspected
• Refer for sigmoidoscopy or colonoscopy where appropriate.^9,7 Guidance on urgency of referral is given below. The rapid access referral may be appropriate, and patient may need immediate admission if bleeding is severe. Further investigations to identify source of bleeding include:
  • Selective mesenteric angiography 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 (10 times more sensitive than mesenteric angiography)
  • CT scanning (helical used when routine workup 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.

This will be determined by the likely diagnosis and the severity of bleeding. It can range from dietary advice and suppositories¹⁰ for benign anorectal conditions to colectomy, super selective embolisation and endoscopic coagulation. It is important to know when to refer. Referral may be urgent (within 2 weeks) to make a diagnosis or as an emergency (immediate) when there is massive bleeding. Routine referral may be appropriate for low risk and benign conditions.⁵

• Refer patients urgently (to be seen within 2 weeks) who have had either:
  Rectal bleeding plus change of bowel habit (increased frequency or change to looser motions) persisting for 6 weeks and are 40 years or older.
  • Palpable rectal or right sided lower abdominal mass.
  • Iron deficiency anaemia without any obvious cause (< 11g/dl in men and <10g/dl in postmenopausal women).
• Patients over 60 with:
  • Rectal bleeding without anal symptoms (anal discomfort, soreness, pruritis ani or local mass) persisting for 6 weeks.
  • Change in bowel habit (increased frequency or change to looser motions) persisting for 6 weeks without rectal bleeding.

Patients who have a change in bowel habit with constipation or infrequent bowel action or abdominal pain without evidence of obstruction have a very low likelihood of bowel cancer. However such patients still need referral for investigation.

The likelihood of complications depends on the cause of rectal bleeding and the severity of bleeding. Generally speaking cases are more likely to produce complications, morbidity and mortality when:

• There is massive haemorrhage
• Surgery is required
• Invasive investigations are required
• Hospital admission is necessary
• The underlying disease is associated with complications (cancer, inflammatory bowel disease)
• In the very young and the old

This again depends on many factors. Mortality is as higher as in the over 60s admitted to hospital. Mortality is as high as 21% in cases of massive haemorrhage in over 65 year olds.

Preventive measures should be aimed at the underlying diseases and better management of both the complications and more severe cases of haemorrhage. Earlier diagnosis and treatment of GIT carcinoma would prevent some cases of haemorrhage, but often it is the bleeding which triggers the diagnostic process. It may be that screening for early occult bleeding will reduce cases of more advanced carcinoma with anaemia and more severe bleeding.^12,13,14,15

Recognition of significant symptoms and appropriate referral are essential to good outcome.
The key recommendations from NICE guidance to improve outcomes in colorectal cancer are:¹¹

• To improve recognition of potential symptoms of colorectal cancer in primary care and in the community.¹⁶
• Efficient systems should be set up to ensure that patients who may have colorectal cancer are rapidly referred for endoscopy.
• Substantial expansion of lower gastrointestinal (GI) endoscopy services. Access to both flexible sigmoidoscopy and colonoscopy should be improved and the focus of diagnostic effort should move from barium enema to endoscopy. (crucial for screening services when they are introduced).
• Cancer Networks and Trusts should review the composition and function of colorectal cancer multi-disciplinary teams (MDTs) and make sure that each MDT has a co-ordinator. They should:
  • Ensure that all patients with suspected or newly diagnosed colorectal cancer are promptly referred to, and managed by, a colorectal cancer MDT.
  • Review operational links with hepatobiliary (HPB) services to ensure that patients with resectable liver metastases are referred to specialist MDTs for assessment.
  • Identify specialist MDTs which will manage patients with anal cancer.
  • Emergency patients (particularly those with intestinal obstruction) should be managed by colorectal cancer MDTs. This may require the development of emergency teams and transfers of patients between neighbouring hospitals.
  • Patients with rectal cancer should be managed by teams trained in all aspects of total mesorectal excision (TME), including pre and post-operative assessment, surgical technique, and the role of clinical oncology.
• All aspects of patient-centred care should be re-assessed. In particular, Trusts should:
  • Improve the provision of appropriately trained staff and resources.
  • Ensure that patients receive all the information they want at all times.
  • Arrange ongoing support for patients and carers from a clinical nurse specialist who is encouraged to play an active part in MDT discussions.