Rectal bleeding

Question 1

Differential diagnoses of Rectal bleeding

Answer 1

1. Hemorrhoids*

Probability diagnosis 
Haemorrhoids/perianal haematoma
Anal fissure
Colorectal polyp 
Diverticulitis
Excoriated skin (anal pruritus)

Serious disorders not to be missed  
Vascular:
•ischaemic colitis
•angiodysplasia (vascular ectasia)
•anticoagulant therapy

Infection:
•enteritis (e.g. Campylobacter, Salmonella)

Cancer/tumours:
•colorectal, caecum
•lymphoma
•villous adenoma

Other:
•inflammatory bowel disease (colitis/proctitis)
•intussusception

Pitfalls (often missed)
Rectal prolapse
Anal trauma (accidental/non-accidental)
Villous adenoma

Rarities:
•Meckel diverticulum
•solitary ulcer of rectum

Question 2

Rectal Bleeding - Key History

Answer 2

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).

Question 3

Rectal Bleeding - Key PE

Answer 3

Key examination

• General inspection (evidence of anaemia) and vital signs
• Abnormal examination, anal inspection, digital rectal examination, proctosigmoidoscopy

Question 4

Rectal Bleeding - Key Investigations

Answer 4

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)

Question 5

Rectal Bleeding - Diagnostic tips

Answer 5

Diagnostic tips

• Black, tarry (melaena) stool indicates bleeding from upper GIT: rare distal to lower ileum.
• Frequent passage of blood and mucus indicates a rectal tumour or proctitis.
• If substantial haemorrhage, consider diverticular disease, angiodysplasia or more proximal lesions (e.g. Meckel diverticulum, duodenal ulcers).
• New bleeding age >55 years demands colonic investigation.
• 80% of rectal tumours are within fingertip range.
• In young adults, diagnosis is likely to be haemorrhoids or a fissure.