Anorectal Fistula
An anorectal fistula is an abnormal channel from the anus or rectum usually to the skin near the anus but occasionally to another organ, such as the vagina.
Most fistulas begin in a deep gland in the wall of the anus or rectum. Sometimes fistulas occur after drainage of an anorectal abscess, but often the cause cannot be identified. Fistulas are more common among people with Crohn's disease or tuberculosis. They also occur in people with diverticulitis, cancer, or an anal or rectal injury. A fistula in an infant is usually a birth defect; such fistulas are more common among boys than girls. Fistulas that connect the rectum and vagina may result from radiation therapy, cancer, Crohn's disease, or an injury to a mother during childbirth.
Symptoms and Diagnosis
A fistula may be painful and may discharge pus. A doctor can usually see one or more openings of a fistula or can feel the fistula beneath the surface. A probe may be inserted to determine its depth and direction. Looking through an anoscope inserted into the rectum and exploring with the probe, a doctor may locate the internal opening. Inspection with a sigmoidoscope, which is a much longer viewing scope, helps a doctor determine whether the problem is being caused by cancer, Crohn's disease, or another disorder.
Treatment
The only effective treatment is surgery to remove the fistula (fistulotomy). During surgery, sometimes the sphincter is inadvertently partially cut. If too much of the sphincter is cut, the person may have difficulty controlling bowel movements. If the person has diarrhea or Crohn's disease, which may delay wound healing, the operation usually is not performed.
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