Why do only humans get hemorrhoids, and why do they target you?

As the saying goes, "Nine out of ten men have hemorrhoids," meaning the incidence of hemorrhoids is extremely high. If you get hemorrhoids and leave them untreated for a long time, the harm can be great, such as causing anemia, constipation, and even affecting male sexual function. Therefore, although hemorrhoids are not a serious illness, they should not be ignored.

Because humans walk upright, which is the biggest difference between humans and other animals, when standing, the pressure in the hemorrhoidal veins increases, making it easier to develop hemorrhoids.

In nature, only humans are advanced vertebrates that walk upright; others are crawling animals. An important difference between upright humans and crawling animals is the distribution of blood vessels in the anal area and the tension of the anus. In addition to straining during defecation like crawling animals, upright humans also experience a vertical gravitational pull from the earth on the anal blood vessels that crawling animals do not have.

Animals mostly walk on four legs, and when crawling, the pressure in the hemorrhoidal veins is zero, so they do not get hemorrhoids. In humans, factors such as fatigue, disease, and diet during labor continuously increase the resistance to venous return in the anal area, leading over time to muscle relaxation, decreased vascular elasticity, and venous congestion, resulting in hemorrhoids. So many human diseases are the price of walking upright, and hemorrhoids are one of them.

So, what exactly are hemorrhoids? This is not a simple question. Doctors and patients often have different understandings. In fact, hemorrhoids can be defined broadly and narrowly. Broadly, hemorrhoids refer to all anal diseases. Narrowly, hemorrhoids refer to what modern medicine calls hemorrhoids, which is what we now call hemorrhoids. Hemorrhoids have many names, such as piles, hemorrhoidal nodules, hemorrhoidal masses, and hemorrhoidal disease. Hemorrhoids can be divided into internal hemorrhoids, external hemorrhoids, and mixed hemorrhoids. The definition of internal hemorrhoids is still controversial. In the past, it was believed that hemorrhoids were a soft mass formed by the tortuous dilation of the venous plexus in the anal canal. The current view is that there are three soft cushion-like tissues in the anus, composed of blood vessels and elastic fibers, medically called anal cushions. Like the rubber gasket in a faucet to prevent leakage, they have the function of maintaining anal continence. If for various reasons these anal cushions undergo pathological changes, such as congestion, edema, hypertrophy, and downward displacement, internal hemorrhoids form. How to distinguish external hemorrhoids from internal hemorrhoids? People often think that those inside the anus are internal hemorrhoids and those outside are external hemorrhoids, but this is not the case. First, we should know that at 2 cm inside the anus, there is an irregular, tooth-like line called the dentate line, which is also the junction between mucosa and skin. Then we can say that internal hemorrhoids are above the dentate line, and external hemorrhoids are below it. This is the real difference between internal and external hemorrhoids. External hemorrhoids can be further divided into three types: thrombosed external hemorrhoids, connective tissue external hemorrhoids, and varicose external hemorrhoids. Mixed hemorrhoids do not simply mean having both internal and external hemorrhoids; rather, they refer to internal and external hemorrhoids in the same position, meaning they are connected and grow together, only then can they be called mixed hemorrhoids.

The causes of hemorrhoid formation are complex, and we will not discuss them for now. However, the formation of hemorrhoids is related to the upright posture of the human body. It is generally believed that animals do not suffer from hemorrhoids. Prolonged standing, prolonged sitting, improper diet, excessive consumption of spicy food, alcohol, and lack of physical activity are all predisposing factors for hemorrhoids.

The main symptom of hemorrhoids is blood in the stool, sometimes manifested as dripping blood during defecation, sometimes as blood in the toilet bowl after defecation, and sometimes as blood on the toilet paper. Regardless, these manifestations are called hematochezia. Generally, the blood is bright red, and the amount can vary from small to large. In severe cases, it can cause massive bleeding, and over time, it may even lead to anemia. Hematochezia is intermittent, sometimes present and sometimes absent, sometimes mild and sometimes severe. Another symptom of hemorrhoids is prolapse. Prolapse refers to the hemorrhoids protruding outside the anus during defecation. Some patients can reduce them spontaneously, meaning after defecation, the hemorrhoids no longer protrude and return to the pre-defecation state. Some patients cannot reduce them spontaneously and need to push them back manually. In more severe cases, even manual reduction is impossible. When the prolapsed hemorrhoids cannot be reduced, leading to secondary infection, edema, necrosis, and obvious pain, it is called incarcerated hemorrhoids. Hemorrhoids also have other symptoms, such as anal dampness and itching, anal pain and discomfort, and incomplete cleaning with paper after defecation.

How to know if you have hemorrhoids? Judging by yourself or listening to others' experiences is often incorrect, and may even delay treatment and lead to adverse consequences, because many patients easily mistake rectal cancer for hemorrhoids, thus delaying treatment. Therefore, it is very necessary to see a doctor. Only through examination can a doctor confirm whether you have hemorrhoids.