There are many causes of intestinal fistula, and intestinal fistula caused by surgery is the most common!

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

The main functions of the intestines are digestion and absorption. If the continuity and integrity of the intestines are destroyed, the digestive fluid and contents in the intestines will leak to other places, such as into the abdominal cavity, outside the body surface, or into other hollow organs. This situation is called intestinal fistula.

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When digestive juices or intestinal contents leak outside the body surface, it is called an extraenteroidal fistula; when they leak into other hollow organs, it is called an intraenteroidal fistula. Extraenteroidal fistula is more common in clinical practice.

1. What causes intestinal fistula?

Common causes of intestinal fistula include surgery, trauma, abdominal infection, malignant tumors, intestinal inflammation, congenital diseases, etc.

Surgery is the most common cause of intestinal fistula. As a surgical complication, it often occurs when the intestinal wall is not sutured properly during gastrointestinal surgery, resulting in leakage of digestive fluid or intestinal contents in the suture area. These fluids may flow out of the body through the abdominal drainage tube, or feces or digestive fluids may overflow from the surgical incision. The symptoms are obvious and easy to identify.

In addition, abdominal trauma can damage the intestinal wall, and intestinal inflammatory diseases such as abdominal abscess, Crohn's disease, ulcerative colitis, intestinal tuberculosis and mesenteric ischemic disease can cause abdominal infection and intestinal necrosis, which in turn promotes the formation of intestinal fistula. Malignant tumors, especially those in the intestine, can also be the cause of intestinal fistula because they invade adjacent tissues.

In addition, radiation and chemotherapy drugs can also damage the small intestine, colon, and rectum, and damage the intestinal mucosa and connective tissue of the intestinal vascular walls. In severe cases, they can lead to intestinal wall necrosis and perforation, thereby inducing intestinal fistula.

2. What are the dangers of intestinal fistula?

Intestinal fistula is a pathological channel between the intestines, between the intestines and other organs or outside the body, which causes intestinal contents to flow out of the intestinal cavity and can cause a series of pathophysiological changes such as infection, fluid loss, malnutrition and organ dysfunction.

Intestinal fistulas can cause diarrhea, nutritional disorders, recurrent abdominal pain, high fever, vomiting, belching with fecal odor, etc. Intestinal fistulas are generally manifested by the formation of fistulas on the body surface, with intestinal fluid and feces flowing out of the fistulas, accompanied by infection, malnutrition, and imbalance of water, electrolytes, and acid-base balance. If intestinal fistulas are not treated in time, they can lead to multiple organ failure and death due to severe infection, severe malnutrition, and reduced immunity.

3. How to treat intestinal fistula caused by abdominal surgery?

A drainage tube is usually placed after abdominal surgery. The 4-6 days after surgery is the peak period for enterocutaneous fistula, especially in gastrointestinal surgery.

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If the drainage tube is in the right position and the drainage is good after surgery, a drip system should be established as soon as possible to implement continuous flushing and negative pressure suction until the sinus is formed about 14 days later, at which time it can be replaced with a double abdominal cannula. If the drainage effect is not good and the presence of abscess cavity is confirmed by evaluation, puncture can be performed under the guidance of CT or B-ultrasound, and then an abdominal drainage channel can be established, and efforts should be made to expand it to the extent that a double abdominal cannula can be inserted.

If postoperative drainage is not smooth, leading to symptoms of sepsis and even the risk of multiple organ failure, laparotomy should be performed promptly to remove the abdominal abscess and ensure the correct placement of the double cannula. For the fistula, a double cannula should be placed to promote it to become a tubular fistula and eventually heal itself; when lying flat, a double abdominal cannula should be placed in the pelvic cavity, left paracolic ditch, right paracolic ditch, and low areas under the liver. In addition, an enteral nutrition supply route needs to be established to lay the foundation for subsequent nutritional support.

In the acute phase, enterocutaneous fistula may be accompanied by organ dysfunction or even failure, which requires controlling bleeding, providing nutritional support, and maintaining water, electrolyte and blood volume balance. After the acute phase, the condition enters a stable stage, the fistula forms a tubular fistula, and vital signs tend to stabilize. When the tubular fistula has a good shape, many patients can achieve self-healing at this stage through effective enteral or parenteral nutritional support. A small number of patients who fail to heal themselves will enter the third stage and require definitive surgery to remove the diseased intestinal segment and reconstruct the digestive tract; some patients with abdominal wall problems will require abdominal wall repair.

Enterocutaneous fistula is a benign disease. After proper treatment or spontaneous healing, most patients with enterocutaneous fistula caused by surgery can fully recover, but some cases may relapse.