Perianal Abscess + Fistula

Question 1

def of perianal abscess

Answer 1

pus collection in perianal region

Question 2

def of perianal fistula

Answer 2

an abnormal chronically infected tract communicating between the perianal skin and either anal canal or rectum

Question 3

how are perianal abcesses classified

Answer 3

on location:
1 submucous
2 subcutaneous

Question 4

how are perianal fistulas classified

Answer 4

Park's classification:
2 intersphincteric (most common)
3 transsphincteric
4 suprasphincteric
5 extrasphincteric

Question 5

aetiology

Answer 5

obstruction + stasis of anal crypt glands leads to infection which spreads to perianal tissues
produces abscesses

Question 6

how do abscesses form fistula

Answer 6

fistulae develop once abscess discharges

Question 7

associations

Answer 7

1 diverticulitis
2 crohns
3 childbirth
4 malignancy (rectal carcinoma)

Question 8

epi

Answer 8

30-40yrs

male>females

Question 9

history

Answer 9

1 constant throbbing pain in the perinuem

2 with fistulae: intermittant discharge

Question 10

what is the perineum

Answer 10

between anus and scrotum/uvula

Question 11

examination

Answer 11

1 tender perianal swelling
2 or small skin opening with discharge
3 PR: an area of hardening indicating abscess/fistula

Question 12

investigations

Answer 12

1 bloods
-FBC, CRP/ESR, blood cultures if pyrexial
2 MRI for complex fistulae
3 endoanal USS

Question 13

management

Answer 13

SURGERY
1 open drainage of abscess
-incision + drainage
2 laying open of fistula
-probe to explore tract
3 low fistulae (fistulotomy to cut away diseased tissue to allow healing)
4 high fistulae (must preserve anal sphincter to prevent incontinence, Seton, suture which allows drainage)

Question 14

when are antibiotics used

Answer 14

cellulitis

Question 15

complications

Answer 15

1 recurrence
2 severe sepsis
3 surgery: incontinence

Question 16

prognosis

Answer 16

high recurrence rate

Question 17

what is goodsalls rule

Answer 17

internal opening of fistula is dependent on location of external opening of fistula
1 IO anterior to anal canal - direct tract
2 IO posterior to anal canal - complex, curved tract

Question 18

what is the management with perinanal fistula secondary to crohns disease

Answer 18

drain acute sepsis

maintain drainage by use of setons (suture which allows drainage)