For details on rectal bleeding in children see separate article Rectal bleeding in children.
The passage of blood per rectum is a very common symptom. It is often attributed by patients to haemorrhoids and they 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, i.e. to the right specialist team and with the correct degree of urgency.
It is difficult to get accurate figures for the relative frequency of the different causes of rectal bleeding. Studies have differing results according to population demographics, 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.
It is also important to remember rare causes. Occasionally, bright red blood appears rectally from massive haemorrhage high up in the GI tract. In as many as 20% of patients no cause can be identified even when there has been considerable blood loss.
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 three classifications according to the amount of bleeding:
Massive lower GI bleeding requires urgent admission.
Important features include:
Patients with rectal bleeding can have bled from anywhere in the GI tract and there are many possible causes. The likely causes can be appreciated from the aetiology and are different in different age groups and different populations.
The different underlying diseases can cause different clinical features. For example:
The investigations chosen will depend on the particular mode of presentation and likely diagnosis. It is important that unnecessary investigation should not delay referral. Rectal examination and FBC are worth performing on all patients prior to referral.
This will be determined by the likely diagnosis and the severity of bleeding. It can range from dietary advice and suppositories 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 two 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.
Referral of suspected cancer
Guidance for referral of suspected lower GI tract cancers:
Guidance for those assessing cases of rectal bleeding in hospital has also been produced.15 This is useful also for those considering referral.
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:
This also depends on many factors. Mortality rate may be 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 GI tract 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.
|Original Author: Dr Richard Draper|
Last Checked: 11 Jun 2012
|Current Version: Dr Hayley Willacy|
Document ID: 2703 Version: 23
|Peer Reviewer: Dr John Cox|