Anorectal Abscess

Question 1

What is an anorectal abscess?

Answer 1

Collection of pus in the anal or rectal region

More common in men than in women

High rates of recurrence

Question 2

Pathophysiology

Answer 2

Plugging of the anal ducts which are supposed to drain the anal glands in the anal wall.

The blockage leads to fluid stasis -> infection

The anal galnds are found in the intersphincteric space which means that infection from the glands spreads to adjacent areas.

Question 3

Common causative organisms

Answer 3

E. colie

Bacteriodes spp.

Enterococcus spp.

Question 4

Categorisation of anorectal abscesses.

Answer 4

1 - Perianal (most common)

2 - Ischiorectal

3 - Intersphinteric

4 - Supralevator

Question 5

Clinical features

Answer 5

Pain in the perianal region exacerbated when sat down

Localised swelling

Itching

Discharge

Can have systemic features like fever, rigors, general malaise or sepsis

Question 6

Examination findings

Answer 6

Erythematous

Fluctuant

Tender perianal mass

Discharging pus

Surrouding cellulitis

Question 7

Examination findings of deeper abscesses

Answer 7

Severe tenderness on DRE

so need further examination under anaesthesia (EUA)

Question 8

Sometimes a CT or MRI scan is warranted.

When?

Answer 8

Complicated

Unclear

Chronic disease

Question 9

Management

Answer 9

Abx with analgesia

Incision and drainage which can be left to heal by secondary intention

Question 10

What should be done after drainage?

Answer 10

Proctoscopy to see if there is any fistula in ano.

If fistula -> Insertion of a seton can be done