Pathogenesis. Hemorrhoids are dilated veins within the anal canal and distal rectum. External hemorrhoids are derived from the external hemorrhoidal plexus below the dentate line and are covered by stratified squamous epithelium. Internal hemorrhoids are derived from the internal hemorrhoidal plexus above the dentate line and are covered by rectal mucosa.
Hemorrhoids are thought to develop in most instances as a consequence of erect posture, straining at stool, heavy lifting, or childbirth. In some patients, portal hypertension predisposes to hemorrhoids; rarely, hemorrhoids develop as a result of an intraabdominal mass.
Hemorrhoids typically cause bleeding, which is detected as streaks of red blood on the stool and toilet paper. Patients also may complain of anal itching or pain. However, severe pain is an unusual symptom unless the hemorrhoid is thrombosed.
Inspection of the anus may reveal bluish, soft, bulging veins indicative of external hemorrhoids or prolapsed internal hemorrhoids. Nonprolapsed internal hemorrhoids cannot be seen externally and are difficult to distinguish from mucosal folds by digital rectal examination unless they are thrombosed. Thrombosed hemorrhoids usually are exquisitely tender.
The anal canal and rectum should be examined by anoscopy and sigmoidoscopy. Symptomatic hemorrhoids usually are accompanied by varying degrees of inflammation within the anal canal. At sigmoidoscopy, the anus and rectum can be evaluated for other conditions in the differential diagnosis of rectal bleeding and discomfort, such as anal fissure and fistula, proctitis and colitis, rectal polyp, and cancer. Barium enema x-ray examination or colonoscopy should be performed in patients over age 50 and in patients of any age whose stool remains positive for occult blood after appropriate treatment for hemorrhoids.
A high-fiber diet, stool softeners, and avoidance of straining at stool and heavy lifting may be sufficient to treat mild hemorrhoidal symptoms. Warm baths twice a day and anal lubrication with glycerine suppositories provide further comfort. Addition of medicated suppositories, such as Anusol-HC (containing hydrocortisone), may help reduce associated inflammation. However, steroid-containing medications should be limited to 2 weeks of continuous use to avoid atrophy of the anal tissues.
Additional treatment usually requires the expertise of a gastroenterologist or surgeon. Rubber-band ligation is usually the first definitive treatment. The procedure requires no anesthesia and produces excellent results in most patients. Injection of hemorrhoids with sclerosing solutions, dilatation of the anal sphincter under anesthesia, electrocoagulation, and laser coagulation are alternatives if rubber banding is ineffective. In patients whose hemorrhoids are severe and refractory to these treatments, surgical excision of the hemorrhoidal plexus may be necessary. Rarely, surgical section of the internal anal sphincter is performed.