Perineal abscesses and fistulae

Question 1

Define Perineal Abscess?

Answer 1

a pus collection in the perineal region within the subcutaneous tissue of the anus.

Question 2

define perineal fistula?

Answer 2

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

Question 3

what are the causes of perianal abscesses?

Answer 3

• Bacterial infection
o E.coli originating from GI
o Staph aureus originating from infection of skin

Question 4

what are the causes of perianal fistulae?

Answer 4

• Fistulae develop as a complication of an abscess
• Fistulae can develop as a complications of Crohn’s disease
(pepper pit perineum)

Question 5

risk factors of anal abscesses and fistulae?

Answer 5

o IBD
o Diabetes mellitus (bad wound healing)
o Malignancy (due to risk of bowel perforation)

Question 6

epidemiology of anal abscesses and fistulae?

Answer 6

• COMMON
• More common in men
• Average age is 40

Question 7

what is the presenting complaint of abscesses and fistulae?

Answer 7

• Constant throbbing pain in the perineum worse on sitting
• Pus-like discharge from the anal region
• Hardened tissue in the anal region
• Personal or family history of IBD
• Can present with spiking temperatures (for abscesses- SBA clue)
• Patients may be unable to defecate due to pain

Question 8

what are the signs of abscesses and fistulae on DRE?

Answer 8

o A thickened area over the abscess/fistula may be felt

o DREs are not always possible due to pain and anal sphincter spasm

Question 9

what is goodsalls law?

Answer 9

o This is a rule that allows you to correlate the location of the internal fistula opening based on the location of the external fistula opening

• openings anterior to anal canal run directly into anal canal
• openings posterior to anal canals follow a curved path.

Question 10

what investigations should be undertaken for perianal abscesses and fistulae?

Answer 10

•	Bloods 
o	FBC  
o	CRP 
o	ESR  
o	Blood culture  
•	Imaging 
o	MRI – gold standard (rarely used) 
o	Trans-perineal USS

Question 11

management plan for perianal abscesses?

Answer 11

• Requires SURGICAL treatment

* Incision and drainage of Abscess

Question 12

management for perianal fistulae?

Answer 12

• low fistula = fistulotomy

- high fistula = seton.

Question 13

when are antibiotics used for abscesses and fistulae?

Answer 13

• in cases of systemic infection

Question 14

what are complications of perianal abscesses and fistulae?

Answer 14

• Recurrence
• Damage to internal anal sphincter
• Incontinence
• Persisting pain

Question 15

prognosis for patients with perianal abscesses and fistulae?

Answer 15

• High recurrence rate without complete excision