Introduction
A fistula is an abnormal connection between body structures. It creates a hollow space or lumen that occurs due to various factors. Most fistulae develop as complications of emergency surgery to treat any other condition or disease. Based on the cause of the fistula, there are different types - traumatic fistula, surgery site fistula, etc.
Enterocutaneous fistula (ECF) is an abnormal connection between the intestinal tract or stomach and skin. As a result, the fluids leak from the stomach or intestine into the space between the intestine or stomach wall and the skin. This area becomes highly susceptible to bacterial infection, leading to abscess formation and infection. 80% of enterocutaneous fistula occur as a complication of surgery, and 20 % occur due to other reasons such as systemic diseases, cancer, etc.
What Is an Enterocutaneous Fistula?
It is an abnormal connection between the intestinal tract or stomach and skin. This causes leakage into the skin. It is also called enteroatmospheric fistula.
How Is Enterocutaneous Fistula Classified?
The enterocutaneous fistula is classified into two types:
1. Primary Fistula: It originates from the inflammation of the intestine.
2. Postoperative Fistula: It occurs as a result of abdominal surgery, especially after bowel surgery.
What Is High Output Enterocutaneous Fistula?
When the drain from the fistula is more than 500 ml per day, it is called high output enterocutaneous fistula.
What Is Low Output Enterocutaneous Fistula?
When the drain from the fistula is less than 200 ml per day, it is called low output enterocutaneous fistula.
Where Do Most Enterocutaneous Fistula Form?
Most enterocutaneous fistulas form in the abdomen, such as the stomach or intestine wall.
What Causes Enterocutaneous Fistula?
80 percent of the enterocutaneous fistula are iatrogenic - develop as a complication after surgery.
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Other surgical complications such as enterotomies or intestinal anastomotic dehiscence possess a high risk of enterocutaneous fistula development.
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Trauma to the abdomen.
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Malignancy or cancer in the abdomen.
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Other systemic diseases such as Crohn’s disease.
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Factors that cause the failure of the fistula closure are known as an acronym “FRIENDS,” in which:
F - Presence of a foreign body in the intestinal tract or the surrounding structures.
R - Previous exposure to radiation.
I - Infection resulting in body mass loss (fats and muscles).
E - Epithelialization of fistula tract.
N - Neoplasm meaning abnormal growth of tissues.
D - Distal part of the intestine is obstructed by thickening.
S - Steroid doses.
What Is Enterocutaneous Fistula Pathophysiology?
The pathophysiology of enterocutaneous fistula includes the connection between the intestine and the skin. When the fluid travels through the intestine and fistula constantly, it enables the epithelial tissue to move or migrate into the fistula and provide coverage to the intestine's inner surface or wall. This process keeps the fistula clear. Epithelialization of the tract also stabilizes the tolerance of the fistula. Based on these factors, a fistula can be of low or high output, short or long, and wide or narrow shape. When a fistula is formed, the intestinal or stomach wall integrity breaks down. This leads to the leakage of fluids from the bowel, resulting in infection and abscess formation.
What Are the Symptoms of Enterocutaneous Fistula?
The common symptoms are:
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Dehydration.
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Malnutrition.
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Weight loss.
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Diarrhea.
How to Diagnose Enterocutaneous Fistula?
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Patient’s Medical History: The patient may have a history of another surgery (which is the iatrogenic cause of the fistula), trauma, injury, or presence of any other medical condition or disease.
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Clinical Examination: The doctor will assess the physical condition of the patient, including fever, weight loss, loss of appetite, etc. It is important to see the presence of pain and tenderness in the affected area.
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Lab Test: Complete blood count (CBC) will help assess the loss of blood or decreased levels of blood, such as anemia and white blood cell count levels. Electrolyte balance in the body will help to assess the electrolyte loss due to dehydration.
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Imaging Test: Computed tomography will help determine the extent of the fistula, such as its opening and ending point. It will also help in identifying the presence of an abscess. Magnetic resonance imaging will be helpful in a small fistula that cannot be identified through computerized tomography. Endoscopy will help diagnose the fistula by directly visualizing the affected area.
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Fistulogram or Fistulography: It is rarely used when other imaging tests are not available. Contrast is injected externally into the fistula opening, and X-rays are taken.
How to Treat Enterocutaneous Fistula?
The treatment of enterocutaneous fistula can be divided into different phases:
Phase 1 - Stabilize the Metabolic and Fluid Imbalance:
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When the enterocutaneous fistula is identified and confirmed, it is important to stabilize the metabolic and fluid imbalance in the patient's body. For example, a blood transfusion should be done immediately if the patient has become anemic. If the albumin protein levels have decreased, then albumin must be administered because albumin helps fluids to stay within blood vessels and improve bowel function. A decrease in albumin levels will increase the risk of fluid leakage from the fistula. If the abscess is present, then drainage of the abscess should be done immediately.
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The fistula drainage is important to control by using a sump catheter because abscess drainage may result in bacterial infection, resulting in abscess formation.
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Skincare around fistula drainage is important. The skin must be protected from lacerations and breakdowns. Different materials, such as ileostomy cement and glycerine, can be used for this purpose.
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After stabilizing the patient's condition, nutritional support is important. Daily caloric requirements of the patient must be calculated, including protein requirement, fluid requirement, etc., and supplementations should be given.
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If needed, enteral feeding should be started - giving nutritional support to the patient through a tube that goes directly into the stomach. A combination of enteral feeding and parenteral nutrition - a form of nutrition given intravenously or in veins through injections - can also be considered.
Phase 2 - Investigation of the Fistula:
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The investigation of the fistula through imaging tests such as a fistulogram is done after stabilizing the patient's condition.
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It will help to identify the anatomic location of the fistula based on which the treatment will be planned.
Phase 3 - Decision Making:
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After confirming the fistula type, its origin, location, and other important characteristics, it is important to wait for the healing process of the fistula to occur before deciding on a surgical procedure. This waiting period must be given enough for the fistula to heal.
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A fistula may take up to four weeks to heal, depending on its anatomy, causes, etc.
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Spontaneous closure of the fistula does not occur in most cases. The fistula takes its own time to heal and close naturally.
Phase 4 - Treatment Plan:
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A surgical approach is required if the fistula has not closed on its own within the expected time, usually four to five weeks. Generally, 95 % of fistula heals with non-surgical treatment and does not require surgical management.
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An incision is made to enter the abdomen if a surgical procedure is required.
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The bowel is dissected to ensure it is completely free from all obstructions.
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This surgical procedure is called bowel mobilization.
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Then the fistula is excised, and the tissues of the bowel connected with the fistula are removed.
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The cut parts of the bowel are again reconnected through the anastomosis - surgically connecting two structures. This establishes the continuity of the bowel.
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To avoid the recurrence of the fistula, the skin where the fistula was crossing over should be closed.
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The incision made on the abdomen wall is closed and sealed with a dressing.
Phase 5 - Supporting Healing Process:
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To support the healing process, the patient must be given adequate supplements and other nutritional support.
What Are the Complications of Enterocutaneous Fistula Surgery?
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Recurrence of the fistula.
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Sepsis or Shock - A dangerous condition in which the body damages its tissues in response to an infection.
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Organ space surgery site infection such as an abdominal abscess.
Conclusion
The iatrogenic cause is the most common cause of enterocutaneous fistula that occurs after surgery, especially an emergency surgery. Patients with a history of trauma or systemic disease are at a high risk of developing enterocutaneous fistula. Enterocutaneous fistula is difficult to manage and operate. Therefore, before planning surgery, it is critical to stabilize the metabolic and fluid imbalance and give enough waiting time for the fistula to heal.
