An anal abscess is an infected cavity filled with pus found near the anus or rectum. It results from an acute infection of a small gland just inside the anus. If the skin over the abscess breaks pus may discharge out.
A fistula is a small tunnel that connects a previously infected anal gland to the skin on the buttocks outside the anus (Perianal area).
An abscess is usually associated with symptoms of pain and swelling around the anus. Individuals may also experience fatigue, fevers and chills. Symptoms related to the fistula include irritation of skin around the anus, drainage of pus and fever.
Clinical examination including digital rectal examination is crucial in the assessment of anal fistula.
Anoscopy is performed to identify the internal opening. Sigmoidoscopy is performed to locate the internal opening and to exclude underlying secondary pathology.
Occasionally, total examination of the large bowel is required either using colonoscopy or barium enema in patients with atypical or recurrent anal fistula who have symptoms suggestive of inflammatory bowel disease.
Endoanal ultrasonography is useful in the total assessment of anal fistula.
Fistulography and magnetic resonance imaging to further delineate complex recurrent anal fistula. Pre-operative assessment of the anal sphincter function may be useful to plan operative approach in patients with recurrent fistula, women with previous obstetric trauma and elderly patients.
An abscess is treated by making an opening to drain the pus from the infected cavity as an OPD procedure under local anesthesia. Patients with a large abscess, diabetes or low immunity may require hospitalization.
Surgery is necessary to cure an anal fistula. Fistula tunnel or fistula tract is totally excised up to the anal sphincter muscle complex. It can be performed as day care basis. Treatment of a deep fistula may require short hospital stay.
There can be mild to moderate discomfort after fistula surgery in the first week which can be controlled with pain medications.
Soaking the affected area in warm water (Hot- sitz bath) is recommended three or four times a day.
Analgesics, Stool softeners or a bulk fiber laxative may also be prescribed.
A gauze pad may be applied to prevent the drainage from soiling clothes.