A patient who feels ill and complains of chills, fever and pain in the rectum or anus could be suffering from an anal abscess or fistula.
WHAT IS AN ANAL ABSCESS?
An anal abscess is an infected cavity filled with pus found near the anus or rectum. Ninety percent of abscesses are the result of an acute infection in the internal glands of the anus. Occasionally, bacteria, faecal material or foreign matter can clog an anal gland and tunnel into the tissue around the anus or rectum, where it may then collect in a cavity called an abscess.
WHAT IS AN ANAL FISTULA?
An anal fistula is always the result of a previous abscess. Just inside the anus are small glands. When these glands get clogged, they may become infected and an abscess can develop. A fistula is a small tunnel that forms under the skin and connects a previously infected anal gland to the skin on the buttocks outside the anus.
WHAT CAUSES AN ABSCESS?
An abscess results from an acute infection of a small gland just inside the anus, when bacteria or foreign matter enters the tissue through the gland. Certain conditions -colitis or other inflammation of the intestine, for example - can sometimes make these infections more likely.
WHAT CAUSES A FISTULA?
After an abscess is drained, a tunnel may persist connecting the anal gland from which the abscess arose to the skin. If this occurs, persistent drainage from the outside opening may indicate the persistence of this tunnel. If the outside opening of the tunnel heals, recurrent abscess may develop.
WHAT ARE THE SYMPTOMS OF AN ABSCESS OR FISTULA?
Anorectal pain, swelling, perianal cellulitis (redness of the skin) and fever are the most common symptoms of an abscess. Occasionally, rectal bleeding or urinary symptoms, such as trouble initiating a urinary stream or painful urination, may be present.
Patients with fistulas commonly have a history of a previously drained anal abscess. Anorectal pain, drainage from the perianal skin, irritation of the perianal skin, and sometimes rectal bleeding, can be presenting symptoms of a fistula.
DOES AN ABSCESS ALWAYS BECOME A FISTULA?
No, a fistula develops in about 50 percent of all abscess cases, and there is really no way to predict if this will occur.
HOW IS AN ABSCESS TREATED?
The treatment of an abscess is surgical drainage under most circumstances. An incision is made in the skin near the anus to drain the infection. This can be done with local anaesthesia or in an operating room under deeper anaesthesia. Hospitalization and antibiotics may be required for patients prone to more significant infections, such as diabetes or patients with decreased immunity.
Up to 50% of the time after an abscess is drained, a tunnel (fistula) may persist, connecting the infected anal gland to the external skin. This typically will involve some type of drainage from the external opening. If the opening on the skin heals when a fistula is present, a recurrent abscess may develop.
Antibiotics alone are a poor alternative to drainage of the infection. The routine addition of antibiotics to surgical drainage does not improve healing time or reduce the potential for recurrences in uncomplicated abscesses.
WHAT ABOUT TREATMENT FOR A FISTULA?
Currently, there is no medical treatment available for this problem and surgery is necessary to cure an anal fistula. If the fistula is straight forward (involving minimal sphincter muscle), a fistulotomy may be performed. This procedure involves unroofing the tract, thereby connecting the internal opening within the anal canal to the external opening and creating a groove that will heal from the inside out.
The surgery may be performed at the same time as drainage of an abscess, although most commonly the fistula doesn’t become obvious until weeks after the initial drainage. Fistulotomy is a long-standing treatment with a high success rate (92-97%). This high success rate must be balanced, however with risk of incontinence (ability to control stool) that comes with division of the anal sphincter muscle.
The two most common procedures utilized in these patients are the endo-anal advancement flap and the LIFT procedure.
HOW LONG DOES IT TAKE BEFORE PATIENTS FEEL BETTER?
Discomfort after fistula surgery can be mild to moderate for the first week and can be controlled with pain killers. Treatment of an abscess or fistula is followed by a period of time at home, when soaking the affected area in warm water (sitz bath) is recommended 3-4 times a day. Stool softeners or a bulk fiber laxative may also be recommended. It may be necessary to wear a gauze pad or mini-pad to prevent the drainage from soiling clothes. Bowel movements will not affect healing.
WHAT ARE THE CHANCES OF A RECURRENCE OF AN ABSCESS OR FISTULA?
If properly healed, the problem will usually not return. However, it is important to follow the directions of a colon and rectal surgeon to help prevent recurrence.
WHO IS A COLON & RECTAL SURGEON?
Colon and rectal surgeons are experts in the surgical and non-surgical treatment of diseases of the colon, rectum and anus. They have completed advanced surgical training in the treatment of these diseases as well as full general surgical training. They are well-versed in the treatment of both benign and malignant diseases of the colon, rectum and anus and are able to perform routine screening examinations and surgically treat conditions.
