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Anal or Rectal Abscess and Fistula Treatment

What is an Anal or Rectal Abscess?

An anorectal abscess is an infected pocket filled with pus found near the anus or rectum.


What is an Anal Fistula and how does it form?

An anal fistula (also called fistula-in-ano) can develop as the result of an incompletely healed initial anal abscess. It can occur in up to 50% of patients who present with an abscess infection. Occasionally, the normal small glands found inside the anal canal can become clogged and become infected, leading to an abscess. The fistula is a tunnel that forms and connects the infected glands in the anal canal to the abscess under the skin. The development of an infection and fistula is usually not caused by a person’s bowel habits, or by how a person cleans-up after a bowel movement. It is usually bad luck. There are other conditions that can put a person a higher risk of developing an anorectal fistula, such as Crohn’s disease, a history of pelvic radiation, anorectal trauma, and anorectal cancer.

What are the signs or symptoms of an Abscess or Fistula?


A patient with an abscess may have pain, redness or swelling in a localized area around the anal canal. This may develop over a period of a few or several days. Generalized fatigue, fever and chills are also common. As the pressure of the infection increases, the overlying skin may rupture, releasing the infection pus. In approximately 50% of people who develop a fistula, the area of the original abscess infection will periodically swell and rupture-open to drain. This can be a repeating cycle. Or, the fistula skin opening may be persistently open, allowing continuous drainage of fluid or pus from the area.

Is any specific testing necessary to diagnose an Abscess or Fistula?


No. Most anal abscesses or fistula-in-ano are diagnosed and managed on the basis of clinical findings during office or surgical examination. Occasionally, additional studies such as ultrasound, CT scan, or MRI can assist with the diagnosis of deeper abscesses or the delineation of an unusual fistula tunnel to help guide treatment.



What is the treatment of an Anal Abscess?

An abscess requires drainage. An incision is made in the skin over the swelling to drain the infection. This can be done in the Emergency Room, or the  doctor’s office with a local anesthetic or in the operating room under deeper anesthesia.
If the infection has created pus, then antibiotics are often ineffective as the sole treatment. Successful drainage of the pus allows the body’s immune system a better opportunity to conquer the infection. There are some conditions in which antibiotics are indicated.  



What is the treatment of an Anal Fistula?

Surgery is almost always necessary to cure an anal fistula. Although surgery can be fairly straightforward, it may also be complicated, occasionally requiring staged or multiple operations. Surgical management of an anorectal fistula can be a significant challenge, and patients are often referred to a board-certified colon and rectal surgeon by other surgeons.  There are several different types of surgical repair available. At surgery, the relationship of the fistula and the anal sphincter muscle is carefully studied. Then an appropriate surgical technique and plan for management are implemented. It is important to remember that multiple surgical efforts may be necessary to achieve the goal of successful fistula cure without undue injury to the anal sphincter muscle.



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