ANAL ABSCESS AND FISTULA
What is an anal abscess and fistula?
Anal abscess is a relatively common condition that most often occurs as the result of infection of an anal gland. Perianal abscess is an emergency and should always be drained in a timely fashion. Delayed or inadequate treatment may occasionally cause extensive or life-threatening tissue necrosis and septicemia.
Anal fistula is an abnormal connection between the anal canal and the skin around the anus. Anal fistula can be classified depending on where the fistula runs in relation to the anal sphincter muscles. Occasionally anal fistula may be related to Crohn’s disease or, very uncommonly, anorectal cancer.
Symptoms of anal abscess and fistula
An anal abscess usually presents with symptoms of pain and swelling. A fistula often presents with recurrent discharge, bleeding, swelling, itching, or repeat episodes of abscess formation.
Diagnosis of anal fistula
Physical examination may reveal the external opening of the anal fistula. It is critical to establish the course of the fistula tract prior to therapy; this can usually be done through an examination under anaesthetic. Sometimes, magnetic resonance imaging (MRI) is used to map the extent of the fistula.
Treatment of anal fistula
The goal of surgery is to eliminate the sepsis whilst maintaining continence. Simple fistulas that do not involve too much of the sphincter muscle can be treated by a lay open or fistulotomy procedure (surgical opening of the fistula tract). Fistulas that involve a significant proportion of the sphincter muscles are more safely treated by initial placement of a seton. A seton is a fine thread [usually of thin, coloured rubber] that allows drainage of sepsis. A subsequent procedure would then be necessary to definitively treat the fistula.