Duodenocolic Fistula

Duodenocolic fistula is an abnormal communication between the duodenum, usually the second or third part, and the colon, usually the hepatic flexure or the proximal transverse colon. It is rare. The fistula leads to reflux of colonic content into the small bowel, causing diarrhea, malabsorption and sepsis.

Causes

• Carcinoma of the hepatic flexure or right colon invading the duodenum (most common cause currently)
• Duodenal peptic ulcer, with perforation into the colon (now rare)
• Crohn disease of the ileocolon or duodenum
• Chronic cholecystitis with an inflammatory mass
• Tuberculosis, actinomycosis, trauma and previous surgery
• Pancreatic disease, retroperitoneal abscess and duodenal diverticulitis

Other malignancy (duodenal, pancreatic head, lymphoma) and radiotherapy are less common causes. The clinical course is progressive malnutrition and recurrent infection. Complications: bacterial overgrowth, bleeding, abscess, bowel obstruction and cachexia.

• Chronic diarrhea with undigested food, steatorrhea and weight loss
• Vomiting of feculent material, foul belching and halitosis
• Epigastric or right upper quadrant pain, anorexia and anemia
• Fever and a palpable right-sided abdominal mass in advanced disease
• Red flags: sepsis, hemorrhage, peritonitis and signs of obstruction

1. CT of the abdomen with oral and intravenous contrast: gas or contrast in the colon passing into the duodenum, mass at the hepatic flexure, thickened wall and local invasion.
2. Barium enema or small bowel contrast study: contrast fills the duodenum from the colon (sensitivity about 85%).
3. Upper gastrointestinal endoscopy with biopsy of the opening, and colonoscopy with biopsy of the mass.
4. MRI enterography for Crohn disease.
5. Laboratory tests: full blood count, albumin, iron, vitamin B12, folate, electrolytes, magnesium, carcinoembryonic antigen and C-reactive protein.

Differentials: gastroenteritis, malabsorption, bacterial overgrowth, chronic pancreatitis, gallstone fistula, duodenal tumor.

1. Optimization: correct fluid and electrolyte deficits, give nutritional support (enteral if possible, or parenteral at 25 to 30 kcal/kg a day with 1.2 to 1.5 g/kg of protein), and treat sepsis with piperacillin-tazobactam 4.5 g IV every 6 hours. Give omeprazole 40 mg IV or orally twice daily.
2. Malignant fistula: curative en bloc right hemicolectomy with partial duodenectomy of the involved wall, with primary closure of the duodenal defect, or a pancreaticoduodenectomy when the pancreatic head is involved.
3. Benign disease and Crohn disease:
   • Colonic resection (right hemicolectomy) with closure of the duodenal defect: primary two-layer closure when the defect is small and the tissue is healthy.
   • For large defects or poor tissue, use a serosal patch from the jejunum, a duodenojejunostomy, or pyloric exclusion with gastrojejunostomy.
   • For Crohn disease, preoperative infliximab 5 mg/kg IV at weeks 0, 2 and 6, then every 8 weeks, with azathioprine 2 to 2.5 mg/kg orally daily to reduce recurrence.
4. Staged approach in unstable patients: temporary diversion then definitive repair at 6 to 8 weeks.
5. Perioperative prophylaxis: cefazolin 2 g IV with metronidazole 500 mg IV before incision, and enoxaparin 40 mg SC daily for 7 days (28 days if cancer).
6. Complications: duodenal leak (5 to 15%), anastomotic leak, intra-abdominal abscess, duodenal fistula, malnutrition and recurrence of Crohn disease.

Follow-up at 2 weeks, 6 weeks and 3 months, with nutritional supplements and vitamin replacement (vitamin B12 1 mg IM every 3 months if the terminal ileum is resected). Counsel on symptoms of leak and malnutrition.