II. Epidemiology
- More common in men (twice risk of women)
- Anorectal Abscess Incidence: >100,000 cases per year in U.S.
- Age: 20 to 60 years old (mean 40 years old)
III. Pathophysiology
- Infection of the 6-12 anal glands and crypts that surround the anus circumferentially
- Occurs at mucocutaneous junction (Dentate Line)
- Intestinal columnar epithelium lies proximal to the Dentate Line
- Squamous epithelium is present distal to the Dentate Line
- Contiguous spread of infection in to ischiorectal space
- Infection spreads through the internal anal sphincter, and into the intersphincteric plane
- Causative organisms: Mixed infection with fecal flora
- Bacteroides fragilis (most common in adults)
- Escherichia coli (most common in children)
IV. Risk Factors
- Crohn's Disease
- Diabetes Mellitus
- Immunodeficiency
- Pregnancy
- Chronic Corticosteroid ues
- Anorectal Trauma
- Radiation fibrosis
- Perirectal tumor
V. Types: Anorectal Abscess
- Superficial: Perianal Abscess (60%)
- Local Perianal Abscess
- Immediately adjacent to anal verge
- Deep: Perirectal Abscess
- Intersphincteric Abscess
- Proximal infection spread through the internal and external anal sphincter
- Ischiorectal Abscess (25%)
- Inferior to levator ani
- Two to 3 cm from anal verge
- Pelvirectal Abscess (Supralevator Abscess)
- Abscess superior to levator ani
- Complicated, deep abscess spread from perianal, intersphincter and Ischiorectal Abscesses
- May also spread from Pelvis (PID, Diverticulitis, Ruptured Appendicitis)
- Intersphincteric Abscess
VI. Symptoms
- Constant, throbbing perianal pain
- Pain may be made worse with Defecation
- Systemic symptoms (e.g. fever, chills, Nausea, Vomiting) may be present with deep space infection
VII. Signs: General
- Palpable, tender mass in perianal area or on Rectal Exam
- Perianal Abscess is superficial and is easily identified as a red, tender fluctuant perianal mass
- Deeper, Perirectal Abscesses may only be identified on Rectal Exam or on imaging
- Purulent drainage may be seen via perianal skin tract
- See Fistula-in-ano
VIII. Differential Diagnosis
IX. Imaging
- CT Pelvis
- Indicated for evaluation of deep space or complicated abscess
- MRI Pelvis
- Indicated for complicated Anal Fistula evaluation
- Endorectal Ultrasound
- Indicated in some cases of complicated Perirectal Abscess
X. Management
- Complete surgical abscess drainage is critical (including breaking up loculations)
- See types above for specific approach
- Perianal Abscess is typically drained bedside
- Deep, Perirectal Abscess is typically drained in the operating room
- Perianal Abscess and Ischiorectal Abscess incision should be made as close to anal verge as possible
- Minimizes length of potential fistula formation
- Wound cultures are not typically useful (polymicrobial)
- Wound packing is not typically recommended (does not alter course)
- Sterile saline irrigation of the abscess cavity may be performed
- However, incision should be long enough to continue to effectively drain
-
General Measures
- Keep area clean and dry
- Stool Softeners (e.g. Colace)
- Sitz baths
- Frequent dressing changes
-
Antibiotics are recommended to reduce Anal Fistula formation
- Treat for 5 day Antibiotic course
- Additional Indications
- Systemic signs of infection
- Accompanying Cellulitis
- Valvular heart disease
- Diabetes Mellitus
- Immunocompromised patient
- Antibiotic coverage (Anaerobes, Gram Negatives)
- See Diverticulitis for nuanced Antibiotic coverage (Perianal Abscess is treated the same)
- Example Regimens (choose one)
- Ciprofloxacin 500 mg orally twice daily AND Metronidazole 500 mg orally three times daily
- Amoxicillin-Clavulanate (Augmentin) 875 mg orally twice daily
XI. Complications
- Fistula-in-ano (complicates up to 50 to 70% of Perirectal Abscess)
- Untreated Anorectal Abscess
- Fecal Incontinence
- Chronic Pain
- Constipation
- Recurrent Anorectal Abscess
XII. References
- Goroll (2000) Primary Care Medicine, Lippincott, p. 426
- Jhun and Cologne in Herbert (2015) EM:Rap 15(9): 17-8
- Marx (2002) Rosen's Emergency Medicine, p. 1951
- Roberts (1998) Procedures, Saunders, p. 649-51
- Sherman, Bahga and Vietvuong (2022) Crit Dec Emerg Med 36(7): 23-9
- Surrell in Pfenninger (1994) Procedures, Mosby, p. 969
Images: Related links to external sites (from Bing)
Related Studies
Concepts | Disease or Syndrome (T047) , Acquired Abnormality (T020) |
ICD10 | K61.1 |
SnomedCT | 91669008 |
Italian | Ascesso perirettale |
Japanese | 直腸周囲膿瘍, チョクチョウシュウイノウヨウ |
English | Perirectal abscesses, perirectal abscess (diagnosis), rectal abscess perirectal, perirectal abscess (physical finding), perirectal abscess, abscesses perirectal, abscess perirectal, peri-rectal abscess, peri rectal abscess, Perirectal abscess, Perirectal abscess (disorder), abscess; perirectal, pararectal; abscess, perirectal; abscess |
Czech | Perirektální absces |
Hungarian | perirectalis tályog |
Dutch | abces; perirectaal, pararectaal; abces, perirectaal; abces, perirectaal abces |
Spanish | absceso perirrectal (trastorno), absceso perirrectal, Absceso perirrectal |
Portuguese | Abcesso perirrectal |
French | Abcès périrectal |
German | perirektaler Abszess |
Ontology: Anorectal abscess (C0267567)
Concepts | Disease or Syndrome (T047) |
ICD9 | 566 |
ICD10 | K61 , K61.2 |
SnomedCT | 266530003, 155793007, 155796004, 197167001, 197160004, 75236001 |
Dutch | anorectaal abces, abces anorectaal, abces van anorectale streken, abces; anorectaal, anorectaal; abces, Anorectaal abces, Abces van anaal en rectaal gebied |
French | Abcès anorectal, Abcès des régions anale et rectale |
German | Abszess anorektal, anorektaler Abszess, Abszess in der Anal- und Rektalregion, Anorektalabszess, Abszess des analen und rektalen Bereichs |
Italian | Ascesso anorettale, Ascesso anale e rettale |
Portuguese | Abcesso anorrectal, Abcesso das regiões anal e rectal |
Spanish | Absceso anorrectal, Absceso de las regiones anal y rectal, absceso anorrectal, SAI (trastorno), absceso anorrectal, SAI, absceso anorrectal (trastorno), absceso anorrectal |
Japanese | 肛門直腸膿瘍, コウモンチョクチョウノウヨウ |
English | Anorectal abscess NOS, Abscess anorectal, Anal & rectal abscess, abscess of anal and rectal regions, Abscess;anorectal, abscesses anorectal, anorectal abscess, abscess anorectal, Anal/rectal abscess, Anal/rectal abscess NOS, Anorectal abscess NOS (disorder), Abscess - anal/rectal, anorectal abscess (diagnosis), Anorectal abscess, Anorectal abscess (disorder), abscess; anorectal, anorectal; abscess, Abscess of anal and rectal regions |
Czech | Anorektální absces, Absces řitní a konečníkové krajiny |
Korean | 항문 및 직장부의 고름집(농양), 항문직장 고름집(농양) |
Hungarian | Analis és rectalis régió abscessusa, anorectalis tályog, anorectalis abscessus |