Rectal Bleeding in Adults
This is a very common presenting complaint and creates a lot of anxiety in the patient. By far the likeliest causes are haemorrhoids or a fissure, but more sinister pathologies should be considered according to the clinical picture, especially in older patients.
- Anal Fissure
- Rectal Carcinoma
- Diverticular Disease
- Villous Adenoma
- Anticoagulant Therapy
- Inflammatory Bowel Disease
- Colonic Carcinoma
- Blood Clotting Disorders (Including Anticoagulants)
- Bowel Ischaemia
Key distinguishing features of the most common diagnoses
|Piles||Fissure||Gastroenteritis||Cancer of Rectum||Diverticulosis|
|Blood and Stool Mixed||No||No||Yes||No||Possible|
|Mass Felt PR||Possible||No||No||Yes||Possible|
|Sentinel anal Skin Tag||No||Yes||No||No||No|
Possible: FBC, ESR/CRP, LFTs, bone biochemistry, U&E, stool for microbiology and faecal calprotectin, FIT, hospital-based lower GI investigations.
Small Print: Clotting screen.
- FBC: Check for anaemia from acute or chronic bleeding; low platelets may cause or aggravate bleeding
- ESR/CRP raised in active inflammatory bowel disease and malignancy
- If malignancy is suspected, LFT, U&E and bone biochemistry are useful early on as a baseline
- Clotting screen: If clotting disorder a possibility; INR if on warfarin.
- Stool specimen: Helpful in the presence of diarrhoea. May show evidence of infective cause (especially Campylobacter) or white cells in inflammatory bowel disease. Faecal calprotectin may be useful in diagnosing IBD. FIT: A useful colorectal cancer ‘rule out’ test in patients at low risk, also commonly required when arranging a two-week referral to help secondary care stratify urgency of investigation.
- Proctoscopy: Helpful in primary care in visualising haemorrhoids and proctitis to confirm a clinical diagnosis.
- Hospital-based lower GI investigations: Necessary if significant pathology is suspected.
- Eighty percent of rectal tumours are within fingertip range. Always do a PR examination unless the diagnosis is manifestly obvious from the history.
- If blood is on the toilet paper and surface of the motions, the cause is likely to be palpable PR or visible on proctoscopy; if mixed in with the motions, referral for further investigation will be required to make a definite diagnosis.
- In young adults, the diagnosis is usually clear from the history and is likely to be haemorrhoids or a fissure. In such cases, if and when you refer, to allay anxiety, emphasise that this is for treatment rather than investigation.
- The presence of diarrhoea with rectal bleeding in young adults suggests gastroenteritis (especially Campylobacter) or colitis.
- Change of bowel habit and weight loss with rectal bleeding are ominous symptoms which should prompt urgent referral.
- Any patient aged 50 or over with unexplained rectal bleeding merits urgent referral to rule out cancer.
- The presence of haemorrhoids does not necessarily clinch the diagnosis – another lesion may be present, especially in the elderly.
- A brisk, painless haemorrhage in an elderly patient is likely to be caused by diverticular disease. Significant amounts of blood can be lost, so assess urgently with a view to admission