HEMORRHOIDS, ANAL-FISSURE, AND CARCINOMA OF THE COLON, RECTUM, AND ANUS DURING PREGNANCY

Hemorrhoids are a condition characterized by anorectal outlet bleeding, anal pain, and anal itching.(13) The pathophysiology is poorly understood. Outdated and disproved theories include most notably that hemorrhoids are caused by varicosities of the inferior rectal veins or by hyperplasia of anal canal endothelium.(4, 13) Anatomic studies suggest that hemorrhoids are caused by the prolapse of anal canal cushions that consist of redundant rectal mucosa, venules, arterioles, arteriolar-venule malformation, smooth muscle, and elastic connective tissue.(14) Anal canal cushions are normal anatomy and probably play a role in maintaining continence. A pathologic state exists when prolapse causes irritation that leads to congestion, engorgement, and bleeding. Thrombosis of vessels below the dentate line (thrombosed external hemorrhoid) causes pain. The precise cause of anal canal cushion prolapse is not known. Multiple factors, however, are thought to be associated with hemorrhoids. These include straining at defecation, constipation absence of valves in hemorrhoidal vessels and draining veins, vascular engorgement secondary to increased intra-abdominal pressure, erect posture, and heredity.(13, 14)