Most gastrointestinal fistulas occur after surgery. Other causes include:

• Blockage in the intestine
• Infection (such as diverticulitis)
• Crohn disease
• Radiation to the abdomen (most often given as part of cancer treatment)
• Injury, such as deep wounds from stabbing or gunshot
• Swallowing caustic substances (such as lye)

Depending on where the leak is, these fistulas may cause diarrhea, and poor absorption of nutrients. Your body may not have as much water and fluids as it needs.

• Some fistulas may not cause symptoms.
• Other fistulas cause intestinal contents to leak through an opening in the skin.

Tests may include:

• Barium swallow to examine the stomach or small bowel
• Barium enema to examine the colon
• CT scan of the abdomen to look for fistulas between loops of the intestines or areas of infection
• Fistulogram, in which contrast dye is injected into the opening of the skin of a fistula and x-rays are taken

Treatments may include:

• Antibiotics
• Immune suppressing medicines if the fistula is a result of Crohn disease
• Surgery to remove the fistula and part of the intestines if the fistula is not healing
• Nutrition through a vein while the fistula heals (in some cases)

Some fistulas close on their own after a few weeks to months.

The outlook depends on the person's overall health and how bad the fistula is. People who are otherwise healthy have a very good chance of recovery.

Fistulas may result in malnutrition and dehydration, depending on their location in the intestine. They may also cause skin problems and infection.

Contact your health care provider if you have:

• Very bad diarrhea or other major change in bowel habits
• Leakage of fluid from an opening on the abdomen or near the anus, particularly if you have recently had abdominal surgery

Entero-enteral fistula; Enterocutaneous fistula; Fistula - gastrointestinal; Crohn disease - fistula

De Prisco G, Celinski S, Spak CW. Abdominal abscesses and gastrointestinal fistulas. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 29.

Li Y, Zhu W. Pathogenesis of Chron's disease-associated fistula and abscess. In: Shen B, ed. Interventional Inflammatory Bowel Disease. Cambridge, MA: Elsevier Academic Press; 2018:chap 4.

Nussbaum MS, McFadden DW. Gastric, duodenal, and small intestinal fistulas. In: Yeo CJ, ed. Shackleford's Surgery of the Alimentary Tract. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 76.

Updated by: Michael M. Phillips, MD, Emeritus Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.