Rectal Bleeding

Patients present with any degree of bleeding from a smear on the toilet tissue to severe haemorrhage. Various causes are presented in Figure R1.

Local causes of bleeding include excoriated skin, anal fissure, a burst perianal haematoma and anal carcinoma. A characteristic pattern of bright bleeding is found with haemorrhoids. It is usually small, non-prolapsing haemorrhoids that bleed.

Black tarry (melaena) stool indicates bleeding from the upper gastrointestinal tract and is rare distal to the lower ileum.

Key history Nature of the bleed, including fresh versus altered blood, mixed with faeces and/or mucus, in toilet bowl or on underwear. Quantity of bleeding: slight, moderate or torrential. Associated symptoms (e.g. weight loss, constipation, diarrhoea, pain, weakness, presence of lumps, urgency, unsatisfied defecation, recent change of bowel habit).

Key examination

• General inspection (evidence of anaemia) and vital signs

• Abdominal examination, anal inspection, digital rectal examination, proctosigmoidoscopy

Key investigations

• FBE and ESR

• Stool M&C

• Faecal occult blood

• Colonoscopy

• Consider abdominal X-ray, CT colonography, angiography, small bowel enema (depending on clinical findings)