Are perianal abscess and anal fistula the same disease? How to treat perianal abscess and anal fistula?

When it comes to diseases in the anus area, the first thing that comes to mind is hemorrhoids, but perianal abscesses and anal fistulas are also common diseases, and perianal abscesses progress very quickly. Once symptoms appear, they must be treated as soon as possible. So let's talk about what perianal abscesses and anal fistulas are and how to treat them?

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01 Causes

In the 19th century, a German Jewish scientist named Robert Remarque proposed that during the development of our embryos, three germ layers will be divided into endoderm, mesoderm and ectoderm.

Our rectum develops from the mesoderm, while the anal canal at the anus develops from the ectoderm. One of them grows inwards and the other grows outwards, and finally they are connected together. Because this seam is in a zigzag shape, it is called the dentate line.

Because the seam is not so neat, a dozen small pockets are formed at this position, called anal sinuses. The anal sinuses open upwards, and the stool flows from top to bottom, so it is easy for some dirt to accumulate in the anal sinuses, which then cause infection and gradually spread along the anal glands. Then, anal fistulas are like earthworms digging holes, running all the way in the tissues around the anus, which forms anal fistulas.

There are many loose spaces around the anus. Once the infection spreads in this area, an anal abscess is formed. Because the pus accumulates very quickly, the tension here increases rapidly, which can cause extremely severe pain. In more serious cases, it can also cause fever. If you understand the principle, you will know that, in general, anal fistula and perianal abscess are different stages of the same disease.

So, are there any special cases? Of course there are. For example, local anal injury, injection treatment, local rectal radiotherapy, these situations may also cause infection, and some systemic diseases, such as diabetes, malnutrition, tuberculosis, etc., may also cause local infection. These situations may also cause perianal abscesses, which have little to do with anal fistulas.

02 How to treat

Generally speaking, the treatment for anal fistula and perianal abscess is quite the same: surgery. You must be wondering, is there no other way besides surgery? Can't we just use conservative treatment? The answer is, don't leave any luck behind. Once you are diagnosed with perianal abscess or anal fistula, surgery is the only way out. The longer you delay, the more time you will have to wait.

Let's first talk about the surgical methods for perianal abscesses. As mentioned earlier, there are many gaps in the tissue structure around the anus, so the perianal abscesses formed in these different gaps have different characteristics, and the surgical procedures are also different, but the ultimate goal is to incise and drain, so that the pus can flow out fully, so as to effectively control the infection.

We must pay attention to the word "sufficient". To achieve the effect of sufficient drainage, the incision must be large, and the surgery for perianal abscess is a contaminated surgery. This interface cannot be sutured, because although the pus can be drained out, the surrounding tissues are still infected. For a period of time after the operation, this position will continue to discharge pus. Therefore, this incision must be fully open to facilitate postoperative drainage.

How to deal with the associated fistula? If the fistula is short, straight and has a simple course, it can be removed during surgery. However, if the fistula is found to have a complex course or cannot be clearly explored during surgery, then two surgeries are required: the first is for incision and drainage, and the second is for fistula removal.

The surgery is not over yet, and postoperative treatment accounts for half of the treatment process. After a period of time after the operation, these infected and necrotic tissues gradually necrotize, fall off, and drain, and then fresh tissues gradually grow from the bottom of the incision to fill the wound surface. Only in this way can the operation be considered successful. But if the bottom has not grown solid yet, the top is sealed, and the infection focus will be sealed inside. This is called false healing. Therefore, in order to prevent the occurrence of this false healing, you must follow the doctor's instructions after the operation, treat the wound regularly, and have regular follow-up visits. The whole process is indeed more troublesome and takes a long time, but this is determined by the characteristics of the disease itself, so during the treatment process, you must listen to the doctor.

The article is produced by Science Popularization China-Starry Sky Project (Creation and Cultivation). Please indicate the source when reprinting.

Author: Sun Yifei, Director of the Medical Education History Research Office, Hebei Medical University

Reviewer: Chen Gang, deputy chief physician, Peking Union Medical College Hospital