What causes hemorrhoids?

Hemorrhoids are common, affecting about 4% of adults in the United States. The hemorrhoidal plexus, a clump of veins composed of rectal veins and superior and inferior hemorrhoid veins, may become engorged due to increased pressure and become inflamed or irritated if a blood clot forms within them.

Why these normal veins become symptomatic is not completely understood. We find hemorrhoids more commonly in those who strain to pass stools or have chronic constipation, diarrhea, prolonged sitting, advanced age, pregnancy, and rarely, pelvic tumors.

The causes of hemorrhoids are similar to the causes of varicose veins. Because the venous system that supplies the rectal area contains no valves, factors that increase venous congestion in the region can lead to hemorrhoid formation. These factors include increased intra-abdominal pressure, as caused by defecation, pregnancy, coughing, sneezing, vomiting, physical exertion, or cirrhosis of the liver; an increase in straining during defecation due to a low-fiber diet; diarrhea; and standing or sitting for prolonged periods of time.

Hemorrhoids are usually caused by increased pressure on the veins in the pelvic and rectal area. As pressure increases, blood pools in veins and causes them to swell. Eventually, the swollen veins stretch the surrounding tissue and hemorrhoids develop.

Bowel habits that can cause increased pressure and lead to hemorrhoids include:

• Rushing to complete a bowel movement. Hurrying can lead to excessive straining and can increase pressure on rectal veins.
• Persistent diarrhea or constipation, which may cause straining and increase pressure on veins in the anal canal.

Other things that can lead to the development of hemorrhoids include:

• Being overweight. Excess weight, especially in the abdomen and pelvis, may increase pressure on pelvic veins.
• Pregnancy and labor. Hormonal changes during pregnancy increase blood flow to the pelvis and relax supportive tissues while the growing fetus causes increased pressure on blood vessels. During labor, hemorrhoids may develop because of the intense pressure on the anal area while pushing to deliver the baby.
• Medical conditions. For example, long-term heart and liver disease may cause blood to pool in the abdomen and pelvic area, enlarging the veins.

Each of us has blood vessels that run along the edges of our anal canal called the hemorrhoidal plexus. When these vessels swell, it results in a hemorrhoid. Common causes of hemorrhoids include poor toilet hygiene (i.e. sitting on the toilet for an excessive amount of time), straining while defecating, and pregnancy. Hemorrhoids frequently cause symptoms, including painless bleeding, anal itching, fecal soilage, and occasionally even pain.

Conservative measures, like improving toilet hygiene, are typically sufficient for treatment. Increasing dietary or supplemental fiber will often decrease bleeding, while sitz baths and various over-the-counter analgesic or steroid creams/suppositories will reduce irritation. If such treatments fail, a simple office technique like rubber band ligation is an effective, quick, and safe way to remove hemorrhoids all together with low rate of recurrence and minimal risk of post-procedure pain, bleeding, and infection.