A fistula is an abnormal passage via a tube-like structure from a normal cavity or tube to a free surface or to another cavity. A persistent intestinal fistula is one on which surgery has been performed, closure of the passage has been attempted, and there is a reopening of the area with drainage.

Some common intestinal disorders that may result in fistulas include: diverticulitis; ulcerative colitis; Crohn's disease; regional enteritis; irritable bowel syndrome (IBS); and infectious diarrhea. Additional causes include: radiotherapy; malignancy; injuries; or previous surgeries.

Signs and symptoms may vary depending on the underlying disease. Some of the common abdominal manifestations include: abdominal pain and tenderness, often in the left lower abdominal quadrant (LLQ); rebound and guarding responses; fever; weight loss; anemia; electrolyte losses; hypoalbuminemia; increased white blood cell (WBC) count; diarrhea; and, possibly, bloody stools. A urinary tract infection (UTI) may develop from an enterovesical fistula.

Diagnostic measures may include: history; physical examination; complete blood count (CBC); erythrocyte sedimentation rate (ESR); carcinoembryonic antigen (CEA); urinalysis; liver function tests; stool cultures; and blood chemistries. In addition, colonoscopy, computed tomography (CT) scan, intestinal biopsies, and guiac stool examinations may be performed.

At first, the underlying disease may be treated medically. Intestinal fistulas are treated with total parenteral nutrition (TPN), but they may recur when oral feedings resume. It takes three to six months of an antineoplastic drug to heal 30 to 40% of fistulas; however, most fistulas require surgical correction. A diverting colostomy may be done for the bowel disorder, and followed later by a surgical resection of the bowel which should stop fistula formation. Medication for diarrhea may be used. Anti-inflammatory medications or broad-spectrum antibiotics may be used to treat the inflammatory conditions.

Fistula formation is a frequent complication of bowel disorders, particularly with Crohn's disease and regional enteritis. These fistulas burrow into retroperitoneal spaces, and may progress upward to the cutaneous level with abscess formation, or spread to the rectal area creating fissures and anal fistulas. Enterovesical fistulas may occur and manifest as a UTI.

• May be entitled to special monthly compensation where the Veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Total plus 60% – Special Monthly Compensation (SMC)

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