Anal Fissures

Question 1

An anal fissure is a _________ or _________ in the lining of the anal canal, immediately within the __________

Answer 1

tear

ulcer

anal margin

Question 2

What is the anal margin?

Answer 2

Perianal skin just exterior to the anal verge

Question 3

What is contained within the anal canal? (5)

Answer 3

Rectum…
(From proximal to distal)
1. Transitional zone including blood vessels
2. Dentate (pectinate) line
3. Internal and external sphincters + overlying mucosa
4. Anal verge
5. Anal margin (perinanal skin)

Question 4

The nerve supply of the superior 2/3 of the anal canal is through the ________________, while the inferior third is supplied by the ________________ through the _____________

Answer 4

*delineation between thirds made by the pectinate/dentate line

Autonomic nervous system via inferior hypogastric plexus

Somatic innervation via inferior rectal nerve

sacral plexus

Question 5

What is the significance of the dentate/pectinate line?

Answer 5

Distinct embryological origins and therefore neuro-vascular supplies:

Above pectinate line (proximal 2/3) supplied by:

• inferior mesenteric artery
• drains to portal venous system
• visceral (autonomic) innervation from inferior hypogastric plexus

Below pectinate line (distal 1/3) supplied by:

• inferior rectal artery (branch of internal pudendal a.)
• drains to systemic venous system
• somatic innervation from pudendal nerve

Question 6

The anal canal above the dentate line is sensitive to which stimuli?

Answer 6

Stretch

Thus, procedures above the line do not necessitate analgesia

Question 7

The anal canal below the dentate line is sensitive to which stimuli?

Answer 7

Pain
Temperature
Touch
Pressure

Thus, procedures below this line necessitate analgesia

Question 8

The internal anal sphincter is made of ___________ muscle while the external anal sphincter is made of _____________ muscle

Answer 8

Smooth

Skeletal

Question 9

As a result of their distinct lymphatic drainage pathways, proximal rectal cancers are more likely to produce ________________ adenopathy, while distal rectal and proximal anal cancers can produce ________________ adenopathy.
Distal anal cancers are more likely to produce ______________ adenopathy.

Answer 9

Mesenteric

Internal iliac

Inguinal

Question 10

The dentate line corresponds to the transition between ____________ and ____________ mucosa in the anal canal

Answer 10

Rectal

Anal

Question 11

What are the clinical features of anal fissures? (3)

Answer 11

Bleeding

Persistent pain on defecation

Linear split in the anal mucosa

Question 12

What is the drug treatment of an acute anal fissure?

Answer 12

*present for less than 6 weeks

Focus on ensuring that stools are soft and easily passed:

• bulk-forming laxatives eg ispaghula husk
• osmotic laxatives eg lactulose

+ short-term use of topical preparations containing local anesthetic or simple analgesic IF prolonged burning pain following defecation

Question 13

Acute anal fissures are those which have been present for less than _______________

Answer 13

6 weeks

Question 14

What is the treatment of chronic anal fissures?

Answer 14

*present for 6 weeks or longer

• GTN rectal ointment 0.4% or 0.2%
• diltiazem hydrochloride (unlicensed)
• nifedipine (unlicensed)

Question 15

What are the disadvantages of GTN rectal ointment? (3)

Answer 15

1. Healing rates with topical GTN are only marginally superior to placebo
2. Side effects are quite high and include headaches (20-30% of patients)
3. Recurrence of fissure after treatment is common

Question 16

What is the management of chronic anal fissures that do not respond to pharmacological treatment?

Answer 16

Specialist referral for local injection of botulinum toxin

Question 17

What is the non-drug treatment of chronic anal fissure?

Answer 17

Surgery; generally reserved for those who do not respond to drug treatment

Question 18

90% of anal fissures are found at the _______________ positions. If the fissures are found elsewhere eg lateral, other underlying causes should be considered

Answer 18

Posterior midline

Question 19

What are the risk factors for anal fissures? (3)

Answer 19

1. Constipation
2. IBD
3. STIs eg HIV, syphilis, herpes