Perineal Abscesses and Fistulate

Question 1

Define perineal abscesses

Answer 1

collections of pus in the perineal region

Question 2

Define anal fistula

Answer 2

An abnormal communication between the anal

canal and perianal skin

Question 3

What are the causes/risk factors of anorectal abscesses?

Answer 3

Risk factors
• Anal fistula
• Crohn’s disease
• Male (2-3x more common in men)

Question 4

What are the causes/risk factors of anal fistula?

Answer 4

Risk factors
• Most anal fistulae are caused by
anal abscess
• Trauma
• Crohn’s disease
• Radiotherapy

Question 5

What are the symptoms of anorectal abscesses?

Answer 5

• Perianal pain

* Inability to urinate

Question 6

What are the symptoms of anal fistula?

Answer 6

• Perianal pain
• Bloody or purulent discharge
• Pruritus ani

Question 7

What are the signs of anorectal abscesses?

Answer 7

• Perianal induration
• Perianal swelling
• Low grade fever
• Tachycardia

Question 8

What are the signs of anal fistula?

Answer 8

• Discharge

* Opening

Question 9

What investigations are carried out for perineal abscesses and fistula?

Answer 9

• FBC - leucocytosis
• CRP/ ESR - elevated
• Blood Culture - positive for bacteria, if sepsis.
• Endoanal Ultrasound - may allow visualisation of the abscess and the fistula.
• MRI - extremely useful. Allows detailed study of the often complex and deep pus-filled tracts. Allows for surgical planning ensuring complete excision

Question 10

What is the management for perineal abscesses and fistula?

Answer 10

Surgical treatment under general anaesthesia:
• Abscesses: Open Drainage of abscesses.
• Fistulae: This depends on the location of the internal opening (using a probe):
- Low fistulae: Fistulotomy.
- High fistulae: Fistulotomy would affect muscles leading to incontinence. A Seton (suture) is used –it first allows for the drainage of an abscess, then can be closed. Alternatively, the external part of the fistula is excised and the internal opening is closed by a mucosal flap.

• Antibiotics: According to the cultured organism. Metronidazole and cefuroxime are common initial regimens

Question 11

What are the complications of perineal abscesses and fistula?

Answer 11

• Recurrence, sepsis and damage to the anal sphincters.

* Surgical complications: Incontinence due to damage of the anal sphincters.