What are enteroendotracheal fistulas and enteroendotracheal fistulas? What are the typical symptoms?

Author: Li Yuanxin, Chief Physician of Beijing Tsinghua Chang Gung Hospital affiliated to Tsinghua University

Reviewer: Song Gang, Chief Physician, Cancer Hospital, Chinese Academy of Medical Sciences

Intestinal fistula refers to a pathological channel between the intestine and other hollow organs, body cavities or body surfaces, through which intestinal contents enter other organs, body cavities or outside the body, causing infection, loss of body fluids and malnutrition. It is generally divided into intestinal fistula and intestinal fistula.

1. What are enteroendotenoid fistula and enteroectoenoid fistula?

Leakage of digestive juice or intestinal contents to the outside of the body is called enterocutaneous fistula. In clinical practice, enterocutaneous fistula is relatively common.

When digestive juices or intestinal contents leak into other hollow organs, it is called an enteroendostomy fistula. For example, when the contents of the small intestine leak into the bladder, it is called an enterovesical fistula; when the contents of the rectum leak into the vagina, it is called a rectovaginal fistula. Fistulas can also form between intestines, such as between the small intestine and the colon, which is called an enterocolic fistula.

Figure 1 Original copyright image, no permission to reprint

Surgery is the most common cause of intestinal fistula, which, as a surgical complication, can be said to be a nightmare for surgeons. It is common in gastrointestinal surgery where the intestinal wall is not properly sutured, resulting in leakage of digestive fluid or intestinal contents in the sutured area. These fluids may flow out of the body through the abdominal drainage tube, or overflow of feces or digestive fluid at the surgical incision. The symptoms are obvious and easy to identify.

Intestinal fistula is relatively rare and usually occurs when there are lesions in the intestine itself, such as intestinal tuberculosis, intestinal tumors, radiation-induced intestinal damage, inflammatory bowel disease, abdominal abscess, mesenteric ischemic disease, etc.

With the widespread use of pelvic tumor radiotherapy, this treatment has significantly prolonged the survival of patients with advanced tumors. However, due to complex conditions such as small intestinal adhesions, radiotherapy may cause intestinal wall damage, tissue ischemia and fibrosis in some patients, which in turn induces intestinal wall perforation and necrosis, and eventually evolves into fistula formation. This phenomenon is quite common. Similarly, rectal damage can also lead to fistulas, among which recto-vaginal fistulas and recto-vesical fistulas are particularly common.

Figure 2 Original copyright image, no permission to reprint

Intestinal fistulas caused by radiotherapy are usually extraintestinal fistulas, but intestinal fistulas can also occur. Compared with intestinal fistulas caused by other reasons, the incidence of intestinal fistulas caused by radiotherapy is relatively high, especially higher than the incidence of intestinal fistulas caused by surgery.

2. What are the typical symptoms of intestinal fistula?

The main cause of intestinal fistula is surgery, especially in abdominal surgery, where drainage tubes are usually placed after surgery, and the symptoms of intestinal fistula are often directly reflected by the patient's complaints. The most common complaints include postoperative abdominal drainage tubes draining intestinal contents, digestive juices or feces, or the above substances flowing out of the surgical incision site, and the symptoms are very obvious.

Of course, some smaller intestinal fistulas do not show the above typical symptoms, but fever is the main manifestation. If the drainage is not smooth, it may lead to abdominal effusion, and surgeons need to be highly vigilant about this. Sometimes, the effusion can be obtained through puncture and drainage, and laboratory tests confirm that it is digestive fluid or intestinal contents, which can confirm the diagnosis.

Intestinal fistula may also lead to a series of problems such as malnutrition, water and electrolyte imbalance, infection, abnormal coagulation function and organ failure, among which malnutrition is a key problem. There are three reasons for this: first, the continuity of the intestinal cavity is damaged, which affects the patient's eating; second, the loss of digestive juice or intestinal contents leads to insufficient absorption of nutrients; third, the body's consumption increases under the state of abdominal infection. These factors work together to easily lead to malnutrition.

In addition, intestinal fistula may also lead to anemia. The causes of anemia include blood loss during surgery; intestinal fistula is not drained in time, digestive fluid corrodes blood vessels in the abdominal cavity, causing intra-abdominal bleeding; and anemia tendency under infection. These factors combined make the incidence of anemia higher.

3. What examinations are needed to diagnose intestinal fistula?

After abdominal surgery, if digestive juices, intestinal contents, or feces appear in the drainage tube, or if digestive juices, intestinal contents, or feces flow out of the incision site, it can be clearly diagnosed as intestinal fistula.

Of course, some professional examinations will be used for further evaluation, especially when the fistula becomes tubular or the fistula opening is small and not obvious, and only manifests as fever and abdominal pain. For example, when the drainage tube is close to the fistula opening and close to the upper digestive tract, methylene blue can be taken orally in the early stage of fistula formation, and its discharge time and amount can be observed regularly to determine the size and location of the fistula. A more professional diagnostic method is to perform a contrast examination, directly inject contrast agent through the fistula opening, and perform a CT scan simultaneously, which can not only show the direction of the fistula, but also observe the contrast agent entering the intestine and its integrity. Once the contrast agent is found to have entered the gastrointestinal tract, the diagnosis can be established.

Imaging evaluation is crucial. It can not only confirm the presence of intestinal fistula, but also determine whether there is an abscess cavity, whether the drainage tube is properly positioned, whether there is the potential for the formation of a tubular fistula, and whether it is possible to achieve self-healing through conservative treatment. In addition, it can help identify factors that affect healing and guide the selection of subsequent treatment options. Continuous imaging evaluation is also necessary throughout the treatment process in order to adjust the treatment strategy according to actual conditions.