Anal Fissure

Question 1

What is an anal fissure?

Answer 1

longitudinal or elliptical tears of the squamous lining of the anal canal (distal to dentate line)

Question 2

How are anal fissures classified?

Answer 2

Acute: <6w OR Chronic: >6w
Primary (due to local trauma) OR Secondary (due to underlying disease)

Question 3

Give 3 risk factors for anal fissures

Answer 3

Constipation
IBD
STIs e.g. HIV, syphilis, herpes

Question 4

Describe the distribution of primary anal fissures

Answer 4

90% of all anal fissures located at posterior commissure (6 o’clock in lithotomy position)

Question 5

List 4 potential causes of trauma leading to primary anal fissures

Answer 5

Chronic constipation/ diarrhoea
Low fibre diet
Anal sex
Vaginal delivery

Question 6

Describe distribution of secondary anal fissures

Answer 6

May occur lateral or anterior to posterior commissure

Question 7

List 5 underlying conditions that may cause anal fissures

Answer 7

Previous anal surgery
IBD
Granulomatous disease e.g. TB
Infections e.g. chlamydia, HIV
Malignancy e.g. Leukaemia

Question 8

List 4 symptoms of anal fissures

Answer 8

Sharp, severe pain during defecation
Rectal bleeding (bright red + minimal)
Perianal pruritus
Chronic constipation

Question 9

Describe appearance of anal fissure on examination

Answer 9

Superficial/ deep laceration in anal canal

Question 10

Give 3 signs of fibrotic and infective changes in chronic anal fissures

Answer 10

Wide, raised edges
Skin tags (sentinel pile) at fissures distal end
Hypertrophied anal papillae at fissures proximal end

Question 11

Describe management of acute anal fissures

Answer 11

Soften stool (High fibre diet, high fluid intake, bulk forming laxatives)
Lubricants e.g. petroleum jelly before defecation
Topical anaesthetics
Analgesia

Question 12

Name 2 bulk forming laxatives

Answer 12

Fybogel
Docusate

Question 13

Describe the management for chronic anal fissure

Answer 13

Continue initial Mx
1. Topical GTN
2. If ineffective after 8w, refer to secondary care

Question 14

What can be performed in chronic anal fissure refractory to medical management?

Answer 14

Sphincterotomy
OR
Botulinum toxin injection

Question 15

Give 2 complications of anal fissures

Answer 15

Chronic anal fissure (if left untreated)
Incontinence (post-sphincterectomy)

Question 16

What is the prognosis of anal fissures?

Answer 16

In most: fissure will heal within ~ 1w
Tx aims to ease pain by keeping the stools soft + relaxing the anal sphincter to promote healing

Question 17

Describe the diagnosis and investigation of anal fissures

Answer 17

Clinical dx
If anal sphincter deficits suspected; may do anal US to examine the internal + external sphincter
DRE NOT conducted in suspected anal fissures due to immense pain

Question 18

What is the pain caused by anal fissures compared to?

Answer 18

“passing broken glass”