An anorectal abscess is a pocket of pus that forms in the anus and/or the area just above it, called the rectum.
Most anorectal abscesses begin as bacterial infections of the glands in the anus that produce mucus. Infection can cause inflammation, which in turn creates a wall around the bacteria and forms an abscess. This protective wall makes it hard for the immune system to fight the bacteria.
Pain in the rectal area is the most common symptom of an anorectal abscess. The pain may be dull, aching, or throbbing. It is worse when the person sits down and right before a bowel movement. After the individual has a bowel movement, the pain usually decreases.
Other signs and symptoms of anorectal abscess include: constipationdrainage from the rectumfever and chillsloss of appetitea mass near the rectum
Most anorectal abscesses are caused by bacteria in the lining of the anus or rectum. Factors that increase a person's risk for an abscess include: chronic constipationdiabetesinflammatory bowel diseases, including Crohn's disease and ulcerative colitisimmunodeficiency disorders, such as HIVpregnancy
Anorectal abscesses cannot always be prevented. Early treatment of erosions of the bowel lining can help prevent an anorectal abscess. Stool softeners can be used to improve chronic constipation. Effective treatment of underlying disorders, such as diabetes, can decrease the risk of abscess formation.
The diagnosis of anorectal abscess begins with a medical history and physical exam. Diagnostic studies of the anus or rectum can determine the size of the abscess. These may include special X-ray tests, such as a CT Scan, MRI or ultrasound. An anoscopy may give the healthcare provider a direct look at the inside of the bowel. A special thin tube with a camera and light on the end of it is inserted into the anus and advanced into the bowel.
An anorectal abscess that is untreated or not fully healed can get worse. It can develop into a fistula or a life-threatening infection. A fistula is an abnormal opening or connection between two organs where none should exist.
An anorectal abscess is not contagious and poses no risk to others.
Treatment of an anorectal abscess usually involves surgery to drain the pus pocket. Antibiotics and pain medicines may be prescribed.
Surgery can bwe complicated by bleeding or an allergic reaction to the anesthesia. Sometimes, surgery in the anorectal region can make an infection worse despite the best surgical technique. Antibiotics and pain medicines can cause allergic reactions and stomach upset.
After successful treatment and recovery, a person can generally return to normal activities.
Someone with inflammatory bowel disease often needs lifelong monitoring by a healthcare provider. Any new or worsening symptoms should be reported to the healthcare provider.
Principles of Surgery, 1998, Schwartz et al.