Anorectal bleeding

Question 1

Probability diagnosis

Answer 1

Haemorrhoids/perianal haematoma

Anal fissure

Colorectal polyp

Diverticulitis

Excoriated skin (anal pruritus)

Question 2

Serious disorders not to be missed

Answer 2

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

Question 3

Pitfalls (often missed)

Answer 3

Rectal prolapse

Anal trauma (accidental/non-accidental)

Villous adenoma

Rarities:

• Meckel diverticulum
• solitary ulcer of rectum

Question 4

Key history

Answer 4

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 5

Key examination

Answer 5

General inspection (evidence of anaemia) and vital signs

• Abd exam
• anal inspection
• digital rectal examination
• proctosigmoidoscopy

Question 6

Key investigations

Answer 6

FBE and ESR

Stool M&C

Faecal occult blood

Colonoscopy

Consider (depending on clinical findings);

• abdominal X-ray
• CT colonography
• angiography
• small bowel enema

Question 7

Diagnostic tips

Answer 7

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
• 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.