Enterocutaneous Fistula

What an enterocutaneous fistula is

A fistula is an abnormal connection between two surfaces lined with tissue. In an enterocutaneous fistula, one end is in the gut and the other on the skin of the abdomen. Fluid from the bowel, which may contain bile, digestive enzymes and stool, leaks through it.

Fistulas are classified by daily output, which guides treatment and outlook:

The location also matters: fistulas from the stomach, duodenum or upper small bowel (jejunum) leak more and are harder to manage than colonic fistulas.

Causes

• After surgery (about 75% to 85%): leaks from a bowel join (anastomosis), accidental injury to the bowel during surgery, or a stitch through the bowel when closing the abdomen. Risk is higher with emergency surgery, malnutrition, infection, steroids and smoking.
• Crohn's disease: inflamed bowel can burrow through to the skin, often near old scars.
• Cancer of the bowel or nearby organs.
• Radiation therapy to the abdomen or pelvis, which damages bowel healing for years.
• Diverticulitis, infections, and an abscess that drains through the skin.
• Trauma such as stab or gunshot wounds.

Symptoms

• Leakage of bowel contents, gas or a foul smell from a surgical wound, drain site or new opening
• Fever, belly pain and redness around the wound, often a few days to a week after surgery
• Raw, painful, broken skin around the opening, caused by digestive enzymes
• Signs of fluid loss: thirst, dizziness, low urine output
• Weight loss and weakness

Diagnosis

1. Examination of the wound and its drainage. Drinking a dye or charcoal that then appears in the drainage can confirm a bowel connection.
2. CT scan with contrast: shows abscesses, fluid collections and blockages further down the bowel.
3. Fistulogram: contrast dye injected into the opening on the skin shows the tract's length and where it joins the bowel.
4. Blood tests: infection markers, electrolytes (sodium, potassium, magnesium), kidney function and albumin.
5. MRI or small bowel studies: especially in Crohn's disease.

Treatment

Specialist centers follow a staged approach often summarized as SNAPP: Sepsis and skin, Nutrition, Anatomy, Planned Procedure.

1. Control sepsis and protect the skin

Infection drives most deaths from ECF. Abscesses are drained, usually with a needle under CT guidance, and antibiotics are given. A wound care or ostomy nurse fits a pouch or a negative-pressure system to collect the output and keep enzymes off the skin. Barrier pastes and rings protect the skin around the opening.

2. Fluids and nutrition

• Fluid and electrolyte losses are measured and replaced, often through an IV.
• Many people need parenteral nutrition (feeding through a vein), especially with high-output fistulas. Others can eat or receive tube feeding into the bowel.
• Medicines such as loperamide, acid suppressants and octreotide can reduce output.

3. Define the anatomy

Imaging shows whether the fistula is likely to close. Factors that prevent closure are summarized by the mnemonic FRIENDS: Foreign body, Radiation, Inflammation or infection, Epithelialization (skin growing into the tract), Neoplasm (cancer), Distal obstruction, and a Short tract under 2 cm.

4. Planned surgery

If the fistula has not closed after about 4 to 6 weeks of good care, surgery is usually delayed for at least 3 to 6 months (often longer), until inflammation has settled and nutrition is restored. Early surgery on an inflamed abdomen has high complication rates. Surgery removes the fistula and the diseased bowel segment, joins the healthy ends, and reconstructs the abdominal wall.

Complications

• Sepsis and abscesses
• Dehydration, kidney injury and electrolyte imbalance
• Malnutrition and intestinal failure
• Skin breakdown
• Complications of long-term IV feeding: line infections and liver problems
• Psychological strain from a long hospital stay

Outlook

About a third to half of fistulas close without surgery, usually within the first 4 to 6 weeks once infection is controlled and nutrition is good. Low-output, colonic and long-tract fistulas close most often. Definitive surgery succeeds in most people, though fistulas recur in a minority. Recovery commonly takes months, and many people need ongoing nutrition support at home.

Frequently asked questions

What is an enterocutaneous fistula?

It is an abnormal tunnel connecting the intestine to the skin of the abdomen, allowing bowel contents to leak out. Most develop after abdominal surgery, but Crohn's disease, cancer, radiation and injuries can also cause them.

Can an enterocutaneous fistula heal on its own?

Yes, many do. About a third to half close without surgery within 4 to 6 weeks, provided infection is controlled, nutrition is good and nothing blocks the bowel downstream. Cancer, radiation damage, Crohn's disease or a very short tract make spontaneous closure less likely.

How long does it take to recover from an enterocutaneous fistula?

Recovery usually takes months. If the fistula closes on its own, it typically does so within 6 weeks. If surgery is needed, it is usually done 3 to 6 months or more later, followed by several weeks of recovery after the operation.

What does a high-output fistula mean?

A high-output fistula drains more than 500 ml a day, usually from the upper small bowel. It causes large losses of fluid, salts and nutrients, so people usually need IV fluids, careful electrolyte monitoring, IV nutrition and medicines to reduce the output.

Why is surgery delayed for an enterocutaneous fistula?

Operating soon after a fistula forms, while the abdomen is inflamed and tissues are fragile, causes high rates of bowel injury and recurrence. Waiting 3 to 6 months or longer lets inflammation settle, improves nutrition and makes surgery safer and more likely to succeed.