Anorectal disorders are a group of medical disorders that occur at the junction of the anal canal and the rectum.
The anal canal, also called the anus, is the opening at the bottom end of the digestive tract and is a combination of external skin and tissue from the digestive tract. It has many sensory nerves and is sensitive to pain. The rectum is the last section of the digestive tract and has a mucus layer as its inside surface. It has very few sensory nerves and is, therefore, relatively insensitive to pain. The anal canal has a ring of muscle, called the anal sphincter, which keeps the anus closed. There are a number of different anorectal disorders.
Causes and symptoms
Hemorrhoids are swollen or varicose veins in the anal canal and rectum. They may become inflamed, enlarged, or protrude from the anorectal area. Hemorrhoids may bleed when passing a bowel movement. The amount of bleeding is typically small. Frequently, hemorrhoids develop because of straining during bowel movements, especially if the person has constipation.
An anal fissure is a tear in the lining of the anus that is usually caused by a hard bowel movement. Fissures are painful and bleed when the tissue is stressed during bowel movements.
Anorectal abscesses are characterized by pus-forming infections in the anorectal region. Painful abscesses form under the skin.
An anorectal fistula is an abnormal opening or channel from the anorectal area to another part of the body. Typically, the channel leads to pockets of skin near the anus. When seen in infants, anorectal fistulas are considered birth defects. These are seen more frequently in boys than in girls. Fistulas are also seen more frequently in people who have other diseases, including Crohn's disease, tuberculosis, cancer, and diverticulitis. Anorectal fistulas also occur following anorectal abscesses or other injury to the anal area. Fistulas are usually painful and discharge pus.
Proctitis is an inflammation of the internal mucosal lining of the rectum. Ulcers of the lining may form and develop into ulcerative colitis. There are many causes of proctitis, including the sexually transmitted diseases chlamydia and herpes simplex infections. Proctitis is frequently seen in homosexual males as a consequence of anorectal infection. Proctitis itself is not painful, but pain may be caused by the infectious agent.
Diagnosis is made by visual inspection of the skin around the anus. Also, the doctor may probe the rectum with a gloved finger. An anoscope is a short instrument that allows the physician to view the inside of the anus. A proctoscope is a longer, rigid viewing tube of approximately six to ten inches in length, which may be used to look for anorectal disorders. A sigmoidoscope is a longer, flexible tube, that allows the physician to view up to about two feet of the inside of the large intestine. Tissue samples and material for microbial culture may be obtained during the examination.
Treatment usually isn't required for hemorrhoids. Most hemorrhoids will heal if the patient takes stool softeners
Berkow, Robert, ed. Merck Manual of Medical Information. Whitehouse Station, NJ: Merck Research Laboratories, 1997.
Edwards, C. R. W., I. A. D. Bouchier, and C. Haslett. Davidson's Principles and Practices of Medicine. Edinburgh: Churchill Livingstone, 1995.
Harrison's Principles of Internal Medicine. Ed. Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.
John T. Lohr, PhD