Anorectal abscess

Background

• Usually begin via blocked anal gland (leads to infection/abscess formation)
  • Can progress to involve any of the potential spaces:
    • Perianal
      • Most common
      • Located close to anal verge, posterior midline, superficial tender mass
    • Ischiorectal
      • 2nd most common
      • Larger, indurated, well-circumscribed, located laterally on medial aspect of buttocks
    • Intersphincteric, deep postanal, pelvirectal
      • Rectal pain, skin signs may not be present
      • Constitutional symptoms often present

Clinical Features

• Perirectal abscesses often accompanied by fever, leukocytosis
  • May only be paplpated via digital rectal exam
• Tender inguinal adenopathy may be only clue to deeper abscesses

Diagnosis

• CT or US can be useful to define deep abscesses (esp w/ pain out of proportion to exam)

Treatment

• All perirectal abscesses should be drained in the OR
• Isolated perianal abscess is only type of anorectal abscess that should be treated in ED
  • Consider either linear incision w/ packing or cruciate incision w/o packing
  • Frequent sitz baths
  • Abx
    • Only indicated for:
      • Elderly
      • Systemic signs (fever, leukocytosis)
      • Valvular heart disease
      • Cellulitis
      • Immunosuppression
    • Piperacillin-tazobactam 3.37gm IV q6hr OR ampicillin-sulbactam 3gm IV q6hr

Source

Tintinalli