Anorectal Abscess / Fistula

Anal Abscess

An anal abscess is an infected cavity filled with pus found near the anus or rectum.

What causes an abscess?

Most abscesses result from an acute infection of a small gland just inside the anus. Less frequent abscesses occur from an infection from an anal fissure or from sexually transmitted disease (STD).   Deep abscesses may be caused from Crohn’s disease or diverticulitis.

What are the Risk Factors for developing an anal abscess?

Some of the risk factors for developing an anal abscess are:

  • Diabetes
  • Chemotherapy drugs used to treat cancer
  • Inflammatory Bowel Disease such as Crohn’s or Ulcerative colitis
  • Anal Sex
  • Weakened Immune System

What are the symptoms of an abscess?

Symptoms of an anal abscess include:

  • Pain
  • Swelling
  • Redness
  • Fever
  • Feeling poorly
  • Sometimes spontaneous drainage of pus. The pus can be bloody.

How is an anal abscess diagnosed?

An in-office examination by a colon and rectal surgeon will generally allow proper diagnosis of an anal abscess. On occasion additional imaging studies may be ordered to assist in the diagnosis of a complex or deep abscess.

What is the treatment of an anal abscess?

The treatment of an abscess is surgical drainage under most circumstances. Antibiotics alone usually cannot treat the problem. If it is a superficial abscess, it can be drained in the doctor’s office with local anesthesia. If the abscess is more complex and deeper, it may require drainage in the operating room.

What is the prognosis after treatment?

Approximately one third of all anal abscesses will resolve and not recur; one third will appear to resolve, but then a recurrent abscess will occur in the future at the same location; in one third of the patients the wound will not heal completely and a low level of persistent drainage will be noted. The latter two events are consistent with an anal fistula.

Anal Fistula

A fistula is a tract or communication from the gland that became infected inside the anus to the peri-anal skin where the abscess cavity drained. This results in persistent drainage, discomfort and irritation. It will require operative management for the fistula to resolve. Antibiotics will not cure a fistula.

What causes a fistula?

A fistula forms when the passage between the anal gland and the skin remains after an abscess has been drained. This is the result of the gland persisting after the abscess has been drained.

How is a fistula diagnosed?

An in-office examination by a colon and rectal surgeon will generally allow proper diagnosis of an anal fistula. On occasion additional imaging studies may be ordered to assist in the diagnosis of a complex or deep fistula.

What is the treatment of an Anal Fistula?

Surgery is required in order to treat an anal fistula.

  1. Simple Fistula

Fistulotomy

If the fistula tract is small and does not involve a lot of sphincter muscle, the tract can be opened from the inside opening to the outside opening and allowed to heal overtime with local wound care.

  1. Complex Fistula. These types of fistula may have a long and deep tract or multiple tracts that involve the sphincter muscle. They are very complicated and difficult to treat. There are several treatment options available depending on the circumstances. The goal is to treat the fistula without causing significant sphincter damage resulting in incontinence or a large defect.
    1. Endorectal Advancement Flap: A flap is created using the rectal wall lining to close over the inside opening of the fistula tract preventing it from being re-infected.
    2. LIFT (Ligation of Intersphincteric Fistula Tract): The fistula tract is identified between the sphincter muscles and tied off on both sides.
    3. Anal Fistula Plug: Plugging the tract with a device made from porcine small intestinal mucosa.

What is the prognosis following fistula surgery?

The recovery is dependent on the extent of the fistula and the procedure performed. Pain and drainage are common. Close follow up following surgery is important as fistulas have a high risk of recurrence.

Meet Our Physicians

Our surgeons are
board-certified Fellows
of the American Society of
Colon & Rectal Surgeons

and the American College
of Surgeons
.

Mari A. Madsen

MD, FACS, FASCRS

 

Steven Proshan

MD, FACS, FASCRS