What is the cause of anal lesions

Nowadays, the incidence of anal diseases is relatively high, and the threat to people's health is also relatively large, so we should pay attention to these lesions. The causes of anal lesions include constipation, infection, pregnancy and childbirth.

(1) Physiological structural defects and upright posture: When the human body is standing or sitting upright, the anus is located low. Affected by gravity, the blood return from the rectal and anal veins is obstructed. The superior rectal vein and its branches lack venous valves, making blood easily stagnant. In addition, the rectal blood vessels are arranged in a special way. When they pass through the muscle layer in different planes, they are easily compressed by feces, making the veins in the loose tissue under the mucosa easily dilated and varicose, resulting in hemorrhoids. So some people say that hemorrhoids are a disease unique to the human body. Four-limbed reptiles such as cows, horses, dogs, rabbits and other animals do not suffer from hemorrhoids, mainly because the anus of reptiles is located high, which is beneficial to the blood return in the anorectal area and is less likely to develop varicose veins in the anorectal area. In addition, near the dentate line, small arteries and veins directly anastomose to form cavernous veins. The muscular layer of the cavernous veins is poorly developed, with fewer elastic fibers and more collagen fibers, making them easy to expand and form hemorrhoids.

(2) Constipation: Prolonged bowel movements or chronic diarrhea can increase abdominal pressure, cause congestion in the anorectal area, and lead to varicose veins. It can even cause the rectal mucosa to separate from the muscle layer and the anal canal to move downward with the stool, which can easily lead to hemorrhoids over time.

(3) Infectious factors: Anal sinusitis, anal gland infection, perianal abscess, dysentery, enteritis, intestinal parasitic disease, colitis, etc. can cause inflammation of the tissues around the lower rectum, affecting the hemorrhoidal veins and causing inflammation, making the walls of the hemorrhoidal veins brittle, and subsequently causing vasodilation and congestion, which can cause or aggravate hemorrhoids.

(4) Pregnancy and childbirth: In pregnant women, the fetus compresses the pelvic veins, obstructing venous return and causing vascular dilation in the anorectal area. At the same time, due to the increase in progesterone levels in the body, water and sodium retention occurs, vascular dilation occurs, and hemorrhoids are induced.

(5) Anal sphincter relaxation: Patients who are elderly and frail or have undergone multiple anal surgeries that have destroyed the integrity of the anal sphincter structure will have hemorrhoidal prolapse aggravated by sphincter weakness.

(6) Portal hypertension: Cirrhosis, portal vein thrombosis, etc. can cause portal hypertension. Since the portal vein system lacks venous valves, it can directly lead to increased pressure in the hemorrhoidal venous plexus and cause hemorrhoids.

(7) Tumors: Abdominal and pelvic tumors, such as colorectal tumors, ovarian tumors, and uterine fibroids, can compress the pelvic veins, obstructing the return of hemorrhoidal veins and causing hemorrhoids.

(8) Genetic factors: Regarding genetic factors, Western medicine has no consensus and further verification is needed.