gastrointestinal disorders
Hemorrhoids
Introduction
Hemorrhoids are dilated vessels of the hemorrhoidal plexus in the anal canal. Symptoms include irritation and bleeding. Thrombosed hemorrhoids are usually painful. Diagnosis is by inspection or anoscopy. Treatment is symptomatic or with rubber banding, injection sclerotherapy, infrared photocoagulation, or sometimes surgery. (See also Evaluation of Anorectal Disorders .) Increased pressure in the veins of the anorectal area leads to hemorrhoids. This pressure may result from pregnancy, frequent heavy lifting, or repeated straining during defecation (eg, due to constipation). Hemorrhoids may be external or internal. In a few people, rectal varices result from increased blood pressure in the portal vein, and these are distinct from hemorrhoids. External hemorrhoidsare located below the dentate line and are covered by squamous epithelium. Internal hemorrhoidsare located above the dentate line and are lined by rectal mucosa. Hemorrhoids typically occur in the right anterior, right posterior, and left lateral zones. They occur in adults and children. 