Ischiorectal Abscess

Aka: Ischiorectal Abscess

1. See Also
   1. Perirectal Abscess
2. Epidemiology
   1. Represents 25% of Perirectal Abscess
3. Pathophysiology
   1. Perirectal Abscess involving ischiorectal space
   2. Anatomic boundaries
      1. Lateral to external sphincter
      2. Below levator ani
4. Signs: Low Abscess
   1. See Perirectal Abscess
   2. Infection of fatty tissue below rectum
   3. Perianal tenderness and swelling 2-3 cm from anal verge
5. Differential Diagnosis
   1. High Abscess
      1. Pelvirectal Abscess
      2. Intersphincteric Abscess
   2. Low Abscess
      1. Perianal Abscess (immediately adjacent to anal verge)
6. Radiology: Intrarectal Ultrasound
   1. Evaluation of complex or suspected high abscess
7. Management
   1. See Perirectal Abscess
   2. Local Incision and Drainage indications
      1. Low abscess without signs of higher spread
      2. Non-toxic appearance
   3. Surgical referral for drainage indications
      1. Signs of fasciitis and deep ischiorectal spread
8. Complications: Deep spread of infection
   1. Posterior rectal space infection (horseshoe abscess)
   2. High Ischiorectal Abscess
9. References
   1. Marx (2002) Rosen's Emergency Medicine, p. 1952
   2. Roberts (1998) Procedures, Saunders, p. 649-51