Perianal or perirectal Abscess
Perianal abscesses are typically polymicrobial with both aerobic and anaerobic bacteria.
-They spread through the external sphincter below the level of the puborectalis and become ischiorectal abscesses.
-Anorectal abscesses are more common in early middle-aged males.
Symptoms & Signs: Severe pain in the anal or rectal area, fever, malaise, purulent rectal discharge ischiorectal abscess: Swelling in the ischiorectal fossa on digital rectal examination
-Diagnosis can usually be made with physical exam alone; CT or MRI help to delineate the anatomy of the abscess
–Erythema, fluctuance, and swelling in the perianal region on external examination
-Digital rectal exam will reveal a painful swelling laterally in the ischiorectal fossa. Treatment: Perianal abscesses are treated with local incision and drainage, while ischiorectal abscesses require drainage in the operating room.
Prognosis: After drainage of an abscess, most patients are found to have a fistula in ano.
-Delayed treatment can result in tissue necrosis and sepsis.
-Surgical referral after drainage recommended because of the risk of fistula formation.
–An anorectal fistula is the chronic manifestation of the acute perirectal process that forms an anal abscess
-The majority of anorectal fistulas originate from an infected anal crypt gland
-Drainage of an anorectal abscess results in cure for about 50% of patients while the remaining 50% develop an anal fistula.
-Causes of fistulas that connect to the rectum include: Crohn disease, Lymphogranuloma venereum, rectal tuberculosis, cancer
Symptoms & Signs: purulent discharge, itching, tenderness, and pain
Diagnosis: Drainage from the internal and/or external openings.
-An indurated tract is often palpable.
-Goodsall’s rule can be used as a guide in determining the location of the internal opening
Imaging studies: Endosonography (EUS), fistulography, CT or MRI show air or contrast material within the fistula.
Treatment: Fistula in ano is treated by surgical excision under anesthesia