Perianal Infection

Question 1

What are the anal sinuses/crypts?

Answer 1

SMall recesses that release mucous when compressed by faeces

-aids evacuation of anal canal

Question 2

What is the most common site of perianal infection?

Answer 2

Anal crypts

Question 3

How do perianal infections typically present?

Answer 3

Visibly red, exquisitely tender swelling next to the anus

Typically ano-receptive males

Question 4

What are the three main types of perianal infection?

Answer 4

Anorectal abscesses
Pilonoidal sinus
Perianal warts

Question 5

What are the management options for perianal warts?

Answer 5

Podophyllin
Cryotherapy
Surgical excision
If 2o to syphillis treat w/ penicillin

Question 6

With what conditions are anorectal abscesses most commonly associated?

Answer 6

Associated w/ Chron’s, DM & malignancy

-caused by gut organisms e.g. E.coli

Question 7

What are the most common sites for anorectal abscesses to form?

Answer 7

Perianal (45%)
Ischiorectal (30%)
Intersphincteric (20%)
Supralevator (5%)

Question 8

What are the management options for anorectal abscesses?

Answer 8

Incision/drainage under LA
-to prevent rupture/fistula formation

Only give abx if signs of systemic infection

Question 9

What causes a pilonoidal sinus?

Answer 9

Obstruction of natal cleft hair follicles

Ingrowing of hair causes FB reaction –> abscess formation OR tracs to skin in a ‘pilonoidal sinus’

Question 10

How does a pilonoidal sinus typically present?

Answer 10

Obese males
Asian/middle eastern
Foul discharge
Pain
Fluctuant swelling

Can have asymptomatic periods

Question 11

What are the management options for a pilonoidal sinus?

Answer 11

Incision and drainage with healing via secondary intention

Question 12

How are perianal infections diagnosed?

Answer 12

Examination/Hx
Examination under anaesthetic/imaging (higher infections)
Operative exploration/MRI

Question 13

What is a fistula in ano?

Answer 13

A track that communicates b/w the skin and the anal canal/rectum

Question 14

What causes a fistula in ano?

Answer 14

Usually an abscess discharging to form a fistula

Question 15

How do fistula in ano present?

Answer 15

Initially as an anorectal abscess

Recurrent episodes of infection

Question 16

What are the risk factors for fistula in ano?

Answer 16

TB
Chron's
Diverticular disease
Rectal carcinoma
Immunocompromise

Question 17

What investigations are appropriate in suspected fistula in ano?

Answer 17

Examination under anaesthetic (v. painful)
MRI
Endoanal USS

Question 18

What is Goodsall’s rule?

Answer 18

Relates external opening of anal fistula to internal opening

• post fistulas have curved track w/ opening in post midline
• ant fistulas have direct opening into anal cavity

Question 19

What is the exception to Goodsall’s rule?

Answer 19

Ant fistulas >3cm from anus

-may drain w/ curved track to opening in post midline

Question 20

What are the management options for fistula in ano?

Answer 20

Fistulotomy (healing by 2o intention)
Fibrin glue (fistula plug)
Seton suture
Metronidazole (if Chron’s)