Perianal abscesses and fistulae

Question 1

What is an abscess?

Answer 1

a collection of pus within a cavity, often due to bacterial infection

Question 2

Where are perianal abscesses located?

Answer 2

the anal verge

Question 3

Where is the anal verge found?

Answer 3

distal end of the anal canal

Question 4

What is the anal verge?

Answer 4

a transitional zone between the epithelium of the anal canal and the perianal skin

Question 5

Give two areas that untreated perianal abscesses commonly extend into:

Answer 5

1. Ischioanal space
2. Intersphinteric space

Question 6

What is the ischioanal space?

Answer 6

a fat filled wedge located lateral to the anal canal and inferior to the pelvic diaphragm

Question 7

Infection of which glands commonly cause perianal abscesses?

Answer 7

cryptoglobular

Question 8

Give 7 risk factors for perianal abscesses:

Answer 8

1) IBD
2) diabetes
3) constipation
4) smoking
5) compromised immune system (HIV/ AIDS)
6) anal sex
7) diarrhoea

Question 9

What disease should patients with recurrent perianal abscesses be screened for?

Answer 9

Inflammatory bowel disease

Question 10

Describe the pain associated with perianal abscesses:

Answer 10

throbbing constant pain in the anal area with greater pain during bowel movements

Question 11

Give 5 symptoms associated with perianal abscesses:

Answer 11

1) swelling in the anal area (red, swollen, tender lump)
2) throbbing pain in the anal area
3) rectal discharge or bleeding
4) fatigue
5) fever/ chills (typically seen in deeper abscesses)

Question 12

What is the gold standard investigation for perianal abscesses?

Answer 12

digital rectal exam

Question 13

Name 3 investigations that may be indicated following positive digital rectal examination for perianal abscesses:

Answer 13

1. STI test
2. IBD test
3. Checks for rectal cancer and diverticular disease

Question 14

What is the gold standard management for perianal abscesses?

Answer 14

surgical drainage

Question 15

Give 3 recommendations following surgical drainage of a perianal abscess:

Answer 15

1. Soak the area with warm bath water 3/4 times a day
2. take laxatives or fibre supplements to ease the discomfort of bowel movements
3. Wear gauze or mini pad to prevent the drainage from soiling their clothes

Question 16

What is a fistula?

Answer 16

An abnormal communication between 2 epithelial surfaces

Question 17

What is a perianal fistula?

Answer 17

a connection between the anorectal canal and the perianal skin

Question 18

What is the most common cause of perianal fistulae?

Answer 18

perianal abscesses failing to heal or reoccur in the same place forming tunnels

Question 19

Describe a ‘low’ fistula:

Answer 19

a fistula that passes through few or no sphincter muscle fibres and is relatively close to the skin

Question 20

Describe a ‘high’ fistula:

Answer 20

a fistula that passes through or above lots of sphincter muscle fibres

Question 21

Describe a ‘complex’ fistua:

Answer 21

a complex fistula may include secondary tracks (branch points) or extend in an almost circumferential manner around the anal canal (horseshoe extension)

Question 22

Give 4 symptoms associated with perianal fistulae:

Answer 22

1) skin irritation around the anus
2) constant, throbbing pain
3) discharge from the anus (pus or blood)
4) difficulty controlling bowel movements (in severe cases)

Question 23

Describe the appearance of perianal fistulae on examination:

Answer 23

they appear as external opening - a small pit in the skin which may be obviously discharging

Question 24

Give 3 methods of investigation for perianal fistulae:

Answer 24

1) DR examination
2) proctosigmoidoscopy
3) MRI

Question 25

How may a perianal fistula feel on digital rectal examination?

Answer 25

the internal opening of a fistula feels like an indentation/ grain of rice

Question 26

What is proctosigmoidoscopy?

Answer 26

using a hollow tube with a tiny light at the end to view the rectum and sigmoid colon

Question 27

What is the gold standard imaging technique for fistula anatomy?

Answer 27

MRI

Question 28

Name 4 management methods for perianal fistulae:

Answer 28

1) Seton
2) fistulotomy
3) fibrin glue
4) fistula plug

Question 29

Describe how Seton can be used to manage perianal fistulae:

Answer 29

thread is placed through the anal fistula track and tied to form a continuous ring between the internal and external openings, allowing patency for drainage
(this does not close the fistula and so secondary treatment is required)

Question 30

What is a fistulotomy?

Answer 30

a surgical procedure that opens a tract through excision

Question 31

What are the three main components of fibrin glue?

Answer 31

1) fibrinogen
2) thrombin
3) calcium

Question 32

Describe how fibrin glue can be used to manage perianal fistulae:

Answer 32

1) the fibrin glue is injected into the fistula track while the patient is under general anaesthesia
2) the glue heals the fistula by inducing clot formation and then encourages growth of collagen fibres and healthy tissue

Question 33

What is a fistula plug made of?

Answer 33

pig small intestine mucosa

Question 34

Describe how a fistula plug can be used to manage a perianal fistulae:

Answer 34

it encourages host cells to populate the plug, ultimately filling the fistula track