Why do hemorrhoids bleed?

Hemorrhoid bleeding is a common symptom, so most of the time we need to pay attention to the causes of hemorrhoids, such as standing or sitting for long periods of time, or traveling long distances with heavy loads, as well as genetic factors and anal infections, all of which may induce hemorrhoids.

1. Anatomical reasons: When a person is standing or sitting, the anus and rectum are located at the lower part. Due to gravity and the pressure of internal organs, the upward venous return is greatly hindered. The rectal veins and their branches lack venous valves, so blood cannot flow back easily and is prone to congestion. Its blood vessels are arranged in a special way and pass through the muscular layer at different heights, which makes them easily compressed by fecal matter, affecting blood return. The veins pass through the loose tissue of the submucosal layer and lack stent fixation around them, making them prone to expansion and buckling.

2. Genetic relationship: The venous wall is congenitally weak, with reduced resistance, and cannot withstand the pressure within the blood vessels, thus gradually expanding.

3. Occupational relationship: Standing or sitting for a long time, carrying heavy loads for a long time, affects venous return, slows blood flow in the pelvis and causes congestion of abdominal organs, causing excessive filling of hemorrhoidal veins, decreased tension of venous walls, and easy congestion and dilation of blood vessels. Insufficient exercise, reduced intestinal motility, slow downward movement of feces, or habitual constipation can compress and stimulate the veins, causing local congestion and blood reflux obstruction, resulting in increased pressure in the hemorrhoidal veins and reduced resistance of the venous wall.

4. Local irritation and improper diet: Exposure to cold or heat in the anus, constipation, diarrhea, excessive drinking and eating spicy food can all irritate the anus and rectum, causing congestion of the hemorrhoidal venous plexus, affecting venous blood return and resulting in a decrease in the resistance of the venous wall.

5. Increased anal venous pressure: Cirrhosis, liver congestion and incomplete compensation of cardiac function can cause anal vein congestion and increased pressure, affecting rectal venous blood return.

6. Increased intra-abdominal pressure: Intra-abdominal tumors, uterine tumors, ovarian tumors, prostate hypertrophy, pregnancy, overeating or sitting on the toilet for too long can all increase the intra-abdominal pressure and hinder the venous blood return.

7. Anal infection: The hemorrhoidal venous plexus first becomes inflamed due to acute or chronic infection, and the elastic tissue of the venous wall gradually becomes fibrotic and weakened, resulting in insufficient resistance, which leads to enlargement and varicose veins. Combined with other reasons, the varicose veins gradually worsen and form hemorrhoids.