Enterocutaneous Fistula (ECF): Things To Know About ECF Including Surgery

Enterocutaneous Fistula (ECF): Things To Know About ECF Including Surgery.

What is Enterococcus Fistula?

Enterocutaneous fistula (ECF) is a medical condition presented with an abnormal connection that develops between the gastrointestinal tract and the skin. As a result, contents of the stomach or intestines leak through to the skin.

Most ECFs occur after bowel surgery. Other causes include infection, perforated peptic ulcer, inflammatory bowel disease, Crohn's disease or ulcerative colitis. An ECF may also develop from an abdominal injury or trauma, such as a stabbing or gun shot.

Patients with ECFs often experience complex problems that require long-term care. This care is provided by a team including surgeons, nurses, enterostomal therapists, social workers and nutritionists who will personalize a treatment plan.

 

At UCSF, enterocutaneous fistulas are treated  by the UCSF Complex Abdominal Surgery Program, a high-volume service whose surgeons perform intricate and challenging abdominal procedures using state-of-the-art surgical repair. 

The multidisciplinary team also includes specialists in nursing, intensive care medicine, wound care, plastic surgery, pharmacology, infectious diseasese, nutritional and physical rehabilitation. 

What causes ECF?

For better memorization of ECF causes, the formula 'FRIEND' is use as follows:

F Foreign body

R Radiation

I Infection or Inflammatory bowel disease

E Epithelialization

N Neoplasm

D Distal obstruction

S Short tract.

  Classification of ECF

Congenital types: tracheoesophageal, vitellointestinal duct, patent urachus, rectovaginal.

Acquired: trauma (postoperative), radiation, malignancy, infection

Output categories 

Low-output fistula: < 500 mL/day

High-output fistula: > 500 mL/day

Three categories Edit

Low-output fistula: < 200 mL/day

Moderate-output fistula: 200–500 mL/day

High-output fistula: > 500 mL/day.

  Pathophysiology of ECF

As ECF usually result from a complication of an underlying disease or injury, proper assessment and management depend on an understanding of the pathophysiology of the fistulae formation process. The primary trigger of any fistula is a loss of bowel wall integrity due to an underlying insult. This will ultimately lead to leakage of bowel content, resulting in abscess formation and irritation and erosion to an adjacent organ or surface. The process may take from days to years depending on the underlying etiology. Iatrogenic surgical injuries may lead to intestinal fistulae within a few days while radiation may take from months to years.

Complex fistulae resulting from surgical procedures are formed by the leakage of intestinal contents that eventually find their way through the path of least resistance to another organ or surface and possibly erosions to more than a single organ. Iatrogenic controlled fistulae are intentionally formed for source control in the management of sepsis. An example of this is the acceptance of an ongoing bowel anastomotic leak controlled through an intraabdominally placed drain. The same concept applies to the external drainage of pancreatic fluid, which may accumulate after pancreatic surgery.

  Histopathology of ECF

The histopathologic examination of an enterocutaneous fistula is usually performed postoperatively and is largely nonspecific. Findings usually show an acute-on-chronic inflammatory reaction in addition to the original pathology of the causative disease. 

The acute inflammation is caused by the primary pathology causing the fistula (diverticular disease, malignancy, etc.), tissue irritation by the flow of intestinal content, and the resulting infection. 

Chronic inflammation is observed in radiation-induced fistula, Crohn's disease, malignancy, and chronic fistulae. 

Giant cell reaction is also seen in Crohn’s, tuberculosis, and actinomycosis. Identifying the fistula histopathology is usually done late and only after surgery. Occasionally, intraoperative diagnosis is made by completing a biopsy of incidentally identified fistulae. 

A frozen section is rarely used and is sometimes indicated to rule out malignancy to plan surgical excision. The surgical excision of malignancy involves en-bloc radical excision of the fistula and adjacent organs to achieve an R0 oncologic resection.

Postsurgical intestinal fistulae usually provoke an intense acute inflammatory reaction with a significant infectious bacterial translocation that may lead to sepsis. Severe septic shock with multiorgan system failure can be the presenting clinical picture on some of these occasions. Source control is the most crucial step in patients' survival in this scenario.

  Evaluation of ECF

The acuity of the fistula presentation will dictate the evaluation approach. Chronic or subacute fistulae, such as enterocutaneous, enterovesical, enterovaginal, or entero-enteric fistulae, are usually evaluated in an outpatient setting. 

The aim of the evaluation in this setting would be to:

1. Confirm the diagnosis, delineating anatomy with the characterization of the site, size, and complexity of the fistula.

2. Identify the underlying disease.

3. Plan for management.

4. Re-evaluate.

5. Follow up progression. 

An acute ECF, as in a postsurgical complication, is usually evaluated in a hospital setting on an urgent basis to verify the diagnosis, rule out other complications, and evaluate appropriate sepsis workup and treatment.

How to diagnose ECF?

Clinical diagnosis 

A clinical assessment usually starts with a thorough history and physical exam.

Laboratory investigation

1. A complete blood count (CBC) to assess the white cell count, rule out blood loss anemia, and assess the hemoglobin level as compared to baseline. Additionally, a low MCV could indicate chronic blood loss anemia or malignancy

2. A comprehensive metabolic panel, to assess electrolyte disturbances, kidney function, and hydration status.

3. Lactate, to assess tissue perfusion and guide resuscitation with other perfusion marker.

  Imaging

Imaging with gastrointestinal (GI) contrast that traverses through the fistula (fistulogram) usually substantiates the diagnosis. On occasion, the contrast is not seen in the fistula itself but is seen in the end organ (bladder, vagina, extra-abdominally), which also provides the diagnosis. Upper GI series, small bowel follow-through, or contrast enema can provide this confirmation. 

A computed tomography (CT) scan, however, is often the initial study, especially in an acute intestinal fistula. A CT scan is highly specific in delineating fistulous tract anatomy and often rules out the presence of an abdominopelvic abscess. A CT scan can also help with surgical planning. 

Magnetic resonance imaging (MRI) may also be necessary when the CT scan does not reveal a fistula but clinical suspicion remains. MRI has the advantage of better soft tissue characterization. It is also useful in complex fistulas such as in complicated Crohn’s disease. A variant of MRI known as magnetic resonance enterorrhaphy is now widely used to rule out small bowel pathology and helps in delineating fistulous anatomy especially in Crohn’s disease.

  Endoscopy

Colposcopy, cystoscopy, gastroduodenoscopy, bronchoscopy, and colonoscopy are occasionally utilized to aid the diagnosis of fistulas. This is done by the visualization of the mucosal surface of the scoped organ. A small area of inflamed, red, and possibly elevated mucosa are signs of possible fistulous tract opening. Unless the fistula is very wide, it is usually difficult to visualize its lumen endoscopically. Endoscopy can provide further information about the underlying disease such as malignancy or Crohn’s disease. Fistulae might be an incidental finding of endoscopy that is performed for other reasons. In this situation, further investigations are required.

Signs and Symptoms

Enterocutaneous fistulas (ECFs) can cause contents of the intestines or stomach to leak through a wound or opening in the skin. This is the signs of ECF.

  Complications of ECF

ECF cause mild to moderate complications as listed below:

Dehydration

Diarrhea

Malnutrition

  Management of ECF

Recognition and Stabilization of ECF 

The initial stage of ECF management consists of its identification, followed by general supportive care with fluid and electrolyte replacement, control of sepsis, nutritional support and control of fistula drainage by pharmacologic means as well as through skin protection.

 

Once a postsurgical or spontaneous ECF is identified, obtaining anatomic information is of the utmost importance to predict the site of intestinal opening and assess the need for surgery. Favorable external fistulas include esophageal, duodenal stump, pancreaticobiliary, and jejunal fistulas with small enteric defects (< 1 cm) and long tracts (> 2 cm). In contrast, gastric, lateral duodenal, ligament of Treitz, and ileal fistulas are less likely to close spontaneously.

Additionally, non-healing ECFs are associated with a Foreign body, Radiation, Inflammation, Infection, Inflammatory bowel disease, Epithelization of the fistula tract, Neoplasms and Distal obstructions (or FRIEND). The presence of any FRIEND component in ECF is an indication for surgical intervention; however, surgery should be performed only after sufficient time has been afforded to restore overall patient condition and allow lysis of the intra-abdominal fibrous adhesions from previous operations.

Fistula output fluids rich in electrolytes, minerals and protein cause electrolyte imbalance and malnutrition.

Fluid replacement therapy is therefore the first step in the management of patients with ECF. Crystalloid, colloid solutions and blood transfusions are generally required during early resuscitation.

After initial resuscitation, septic complications need to be controlled. Treatment is comprised of intra-abdominal infection control with antibiotics, computed tomography (CT)-guided drainage or sometimes open drainage for a "controlled fistula". A controlled fistula refers to an ECF without evidence of sepsis (high fever, rigors, and hypotension), or localized infection (cellulitis, pneumonia). 

If the intestinal contents drain out through the matured tract, there is no longer intraperitoneal contamination or fluid accumulation to cause septic problems.

Sufficient parenteral or enteral nutritional support should be provided when the septic problems are under control. Parenteral nutrition has been shown to affect the spontaneous closure of ECF (5-8). Recently, enteral feeding was found to have a protective effect on the mucosal barrier and immunologic function of the bowel, even in patients with high-output ECF. Enteral feeding also improves hepatic protein synthesis. These advantages suggest that early enteral feeding with the combination of parenteral nutrition is a key component of nutritional support in patients with ECF. A regular supplementation of trace minerals such as copper, zinc, and a vitamin complex is generally recommended.

A fistula output greater than 500 mL per day is classified as a high-output fistula and less than 200 mL is classified as a low-output fistula. Fistula output is a significant single prognostic factor for determining the possibility of spontaneous closure and mortality. Control of output is therefore also very important in achieving spontaneous closure.

Traditionally, Nil Per Os (NPO) and nasogastric suction have been used to decrease output, but there is little evidence to support the effectiveness of these strategies. H2-receptor antagonists and proton pump inhibitors are recommended to control fistula output. 

Somatostatin and its analog, octreotide, inhibit endocrine and exocrine secretion in the GI tract. Recent randomized trials did not consistently show a positive effect of octreotide on fistula closure or a reduction in fistula output (12-15). High doses of antimotility drugs such as loperamide (up to 36 mg daily) and codeine phosphate (up to 240 mg daily) are also used to decrease fistula output.

Because the small bowel contents that drain from an ECF are rich in digestive enzymes and electrolytes, skin protection is a crucial step in wound management. It also aids in the secure closure of the abdomen when surgery is mandatory to control the fistula. Skin should be protected from maceration and breakdown when stoma appliances and protective films are used. 

Several studies of vacuum-assisted closure (VAC) reported successful closure of ECF but the main advantages of VAC is skin protection and ease of dressing. Fibrin glue has also been introduced to close ECF, but the success of the study was not definitive due to the small sample size.

Investigation to Defining the Anatomy of ECF.

After seven to ten days of general supportive care to stabilize patients and fistula output, an investigation to determine the anatomic location of the ECF should be considered. The gold-standard for examination of fistula anatomy involves a fistulogram using water-soluble contrast material. 

The information gained via a fistulogram includes:

1. the source of the fistula

2. the nature of the fistula such as length, course and relationship to the bowel

3. the absence or presence of bowel continuity (end vs. side fistula)

4. the absence or presence of distal obstruction

5. the nature of the bowel adjacent to the fistula (inflammation and stricture)

6. the absence or presence of an abscess cavity in communication with the fistula. Other studies such as abdominal CT scans and MRI of the abdomen also provide useful information in selected cases.

  Decision Making for Surgery 

The duration of conservative management should be based on the anatomic studies of the fistula tract. In the absence of the adverse prognostic factors (FRIEND) described previously, the reported success rate of fistula closure varies from 30% to 74% in patients within a time frame of 4 to 12 weeks.

Determining the optimal time for surgical intervention has not been well defined in the literature. However, surgery should be delayed until the intra-abdominal and systemic conditions of the patient are conducive to major surgery. Intraperitoneal adhesion can be performed from as early as postoperative day 4 and adhesive procedures are most frequently performed at postoperative day 35. Evenson and Fischer proposed waiting at least four months from the date of the previous operation.

 

Datta et al. delayed the operation for a median of nine months from the initial surgery or the occurrence of a fistula. The timing of definitive surgery should be individualized according to patient characteristics.

  Surgery for ECF 

The aims of surgery for ECF are:

1. Refunctionalization of the entire bowel

2. Resection of the fistula with end-to-end anastomosis of the bowel

3. Secure abdominal wall closure.

 

Once surgery is planned, care should be taken not to injure the adjacent bowels while opening the abdomen. The fistula tract is detected by staining with methylene blue or guided probes. After identifying the fistula opening in the bowel, resection of the diseased bowel and end-to-end anastomosis is the preferred method compared to over-sewing the fistula opening of the bowel, as recurrent fistula is more likely after over-sewing (36%) than resection (16%). To facilitate early feeding and decompression of the proximal bowel, selected cases require gastrostomy, diverting ileostomy or jejunostomy.

Abdominal closure is challenging when fistula closure is attempted. Skin defects and the increased probability of wound contamination make secure skin closure difficult. Wound complications can result in new or recurring ECF. To promote normal healing of the abdominal wound after surgery, optimal parenteral or enteral nutrition with a supplement comprised of trace minerals and vitamins is essential.

CONCLUSION

Treatment of ECF remains a surgical challenge despite the recent improvement of supportive patient care. Once ECF occurs, adequate stabilization of the patient, a thorough investigation of the fistula anatomy, and non-operative management should intially be attempted. If surgery is required, careful planning, meticulous dissection, resection of the bowel, reanastomosis and reconstruction of the abdominal wall are critical. A multi-disciplinary team approach with a gastroenterologist, interventional radiologists, dieticians, enterostomal therapy nurses and surgeons will maximize successful ECF closures.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3341456/

https://en.m.wikipedia.org/wiki/Enterocutaneous_fistula

https://www.cureus.com/articles/30483-enterocutaneous-fistula-a-simplified-clinical-approach