Anal Abscess and Fistula
Overview
An abscess is a localized pocket of pus caused by infection from bacteria. It can occur in any part of the body. When bacteria seep into the underlying tissues in the anal canal, an abscess may develop.
A fistula is a tiny channel or tract that develops in the presence of inflammation and infection.
Since fistulas are infected channels, there is usually some drainage. Often a draining fistula is not painful, but it can irritate the skin around it. An abscess and fistula often occur together. If the opening of the fistula seals over before the fistula is cured, an abscess may develop behind it.
Causes
Certain conditions such as Crohn's disease or conditions that reduce the body's immunity are more likely to develop anal abscesses and fistulas.
Symptoms
Symptoms of Anal Abscesses
An abscess causes tenderness, swelling, and pain. These symptoms clear when the abscess is drained. The patient may also complain of fever, chills, and general weakness or fatigue.
Symptoms of Anal Fistula
A fistula is a tiny channel or tract that develops in the presence of inflammation and infection. It may or may not be associated with an abscess, but like abscesses, certain illnesses such as Crohn's disease can cause fistulas to develop. The channel usually runs from the rectum to an opening in the skin around the anus. However, sometimes the fistula opening develops elsewhere. For example, in women with Crohn's disease or obstetric injuries, the fistula could open into the vagina or bladder.
Since fistulas are infected channels, there is usually some drainage. Often a draining fistula is not painful, but it can irritate the skin around it. An abscess and fistula often occur together. If the opening of the fistula seals over before the fistula is cured, an abscess may develop behind it.
Diagnosis
Diagnosis of an abscess is usually made on examination of the area. If it is near the anus, there is always pain, and often redness and swelling. The physician will look for an opening in the skin (a sign that a fistula has developed), and try to determine the depth and direction of the channel or tract of the fistula. However, signs of fistula and abscess may not be present on the skin's surface around the anus. In this case, the physician uses an instrument called an anoscope to see inside the anal canal and lower rectum.
Whenever the physician finds an abscess, and especially a fistula, further tests are needed to be sure Crohn's disease is not present. Blood tests, x-rays, and a colonoscopy (a lighted, flexible scope exam of the bowel or colon) are often required.
Treatments
Treatment for Anal Abscess
An abscess must be surgically opened to promote drainage and relieve pressure. This is often done in the physician's office under local anesthesia. However, patients with a large or deep abscess, or those who have other conditions, such as diabetes, may be admitted to the hospital for the procedure.
Antibiotics cannot take the place of draining an abscess. Antibiotics are carried by the bloodstream but do not reach the pus within the abscess. However, they are usually prescribed along with surgical drainage, especially if the patient has other serious diseases, such as diabetes or those associated with reduced immunity.
Treatment for Anal Fistula
Treatment of anal fistula often varies, depending on whether Crohn's disease is present. Crohn's disease is a chronic inflammation and may include the small intestine, colon, or both. As noted, the physician will often do tests to see if this disease is present. If it is, then prolonged treatment with a variety of medications, including antibiotics, is usually undertaken. Often these medications will cure the infection and heal the fistula.
If Crohn's disease is not present, it still may be worthwhile to try a course of antibiotics. If these do not work, surgery is usually very effective. The surgeon opens the fistula channel so that healing occurs from the inside out. Most of the time, fistula surgery is done on an outpatient basis or with a short hospital stay. Following surgery, there may be mild to moderate discomfort for a few days, but patients usually have a short recovery period.