Anorectal abscess

Background

Usually begin via blocked anal gland (leads to infection/abscess formation)
- Can progress to involve any of the potential spaces.

	Perianal	Ischiorectal	Intersphincteric, deep postanal, pelvirectal
Epidemiology	Most common	Second most common	Least common
Symptoms	Located close to anal verge, posterior midline, superficial tender mass	Larger, indurated, well-circumscribed, located laterally on medial aspect of buttocks	Rectal pain, skin signs may not be present
Comments	High incidence of fistula formation even with drainage		Constitutional symptoms often present

Worsening pain around bowel movement, with decreased pain post rectal evacuation
Perirectal abscesses often accompanied by fever, leukocytosis
- May only be paplpable via digital rectal exam
Tender inguinal adenopathy may be only clue to deeper abscesses

CT with IV contrast can be useful to define deep abscesses (especially with pain out of proportion to exam)
May consider ultrasound or MRI as alternatives

All perirectal abscesses should be drained in the OR
All anorectal abscess requires surgical referral and followup
Common bacteria: Staphylococcus aureus, Escherichia coli, Streptococcus, Proteus and Bacteroides
Isolated perianal abscess is only type of anorectal abscess that should be treated in ED
- Consider either linear incision with packing, elliptical incision, or cruciate incision with out packing
- Frequent sitz baths

Causative organisms: Mixed infection with fecal flora for anaerobes and Gram Negatives (Bacteroides fragilis and Escherichia coli)

Only indicated for:^[1]^[2]

Treatment options:

Authors: