Gastrocolic fistulization in Crohn’s disease: a case report and a review of the literature

Discussion

Historically, gastric fistulas to the colon tended to be of the gastrojejunocolic type and occurred in the context of marginal ulceration after gastroenterostomy for the treatment of peptic ulcer disease.2^,3 Gastrocolic fistulas unrelated to previous operations for duodenal ulcer are rare, the commonest causes being carcinomas of the stomach and transverse colon.2^,3 Other rare causes of gastrocolic fistulas include trauma, intra-abdominal and pancreatic abscesses, 3 tuberculosis, syphilis, pancreatic carcinoma,4 renal carcinoma, gastric lymphoma, 5 diverticulitis6 and carcinoid of the transverse colon.7 Although the incidence of internal fistulization in Crohn’s disease is estimated to be 20% to 35%,8^,9 the fistulas are rarely of the gastrocolic variety. Gastrocolic fistula as a complication of inflammatory bowel disease was first reported in 1937 by Bargen and associates from the Mayo Clinic.10 At that time, the gastrocolic fistula was thought to be a complication of ulcerative colitis. However, that case in addition to 2 others of gastrocolic fistulas in 1939 and 1957 were reported at a time when granulomatous colitis was not yet considered a separate entity.11^,12 Crohn’s disease involving the colon was first identified as a distinct entity in 1960 by Lockhart-Mummery and Morson,13 so in retrospect it is likely that these fistulas were actually secondary to Crohn’s disease. Since then, 29 cases have been reported (Table I1^,3^–5^,8^,10^–12^,14^–29).

Development of a gastrocolic fistula secondary to Crohn’s disease is thought to be a result of colitis in the transverse colon with deep ulceration and subsequent fibrosis and fistula formation to the adjacent stomach. This theory is supported by previous reports that consistently show deep ulceration and pseudopolyp formation in the area of the colon where the fistulous tract originates, yet usually without evidence of Crohn’s disease in the stomach where the fistula ends. Hence, it has been suggested that the correct term for this fistula would be “colonogastric” fistula.26

The classic triad of symptoms in patients with gastrocolic fistulas secondary to Crohn’s disease comprises diarrhea, weight loss and fecal halitosis or vomiting but is only present in 30% of the cases.19 Diarrhea, weight loss and abdominal pain are seen in approximately 50% of patients with Crohn’s-related gastrocolic fistulas,29 but these symptoms can easily be attributed to an uncomplicated exacerbation of the underlying disease process. Hence, it is very difficult to determine the presence of a gastrocolic fistula based on history alone. The presence of feculent vomiting or fecal halitosis, which are pathognomonic of a gastrocolic fistula, may help in the diagnosis.11^,15 The symptoms associated with Crohn’s-related gastrocolic fistulas are thought to be secondary to reflux of colonic contents through the fistulous tract with secondary injury to the upper gastrointestinal tract. This retrograde flow of fecal material may result in bacterial overgrowth and be responsible for the debilitating diarrhea and malnutrition that occur with a gastrocolic fistula.29 Vitamin B12 malabsorption may occur, but this study was not conducted in our patient.

Physical findings in a patient with a gastrocolic fistula usually include malnourishment and dehydration.2 Abdominal findings are often nonspecific and minimal; findings may be limited to diffuse abdominal tenderness and distension. 19 Laboratory indices are also nonspecific and are usually limited to electrolyte abnormalities related to the vomiting and diarrhea plus anemia, hypoproteinemia and avitaminoses secondary to the patient’s malnourished state.3^,19 Plain films of the abdomen are usually nonspecific; in this case, the abdominal series showed a distended stomach and absence of gas in the distal bowel, features that could be explained by a functional or mechanical obstruction secondary to the inflammatory process in an uncomplicated exacerbation of Crohn’s disease.

The diagnosis of a gastrocolic fistula is usually confirmed by a barium enema study, which is reported to have close to 100% diagnostic accuracy in revealing the fistula.14 Upper gastrointestinal barium study is only effective in disclosing gastrocolic fistulas in approximately one quarter to one third of the cases;14^,21 this is likely because the fistulous opening is usually so small that contrast material preferentially passes through the pyloric channel as the stomach empties by antral contraction.20 Although esophogastroduodenoscopy and colonoscopy do not demonstrate the fistula well, these examinations are essential preoperatively because they delineate the extent and severity of the disease and hence provide useful information on which the surgeon can base a decision as to the type of resection required.26

Medical therapy may play a role in managing Crohn’s-related gastrocolic fistulas. Greenstein and associates27 reported that 2 patients in their series became asymptomatic and showed radiologic closure of the fistulas with prolonged courses of 6-mercaptopurine. However, the potential toxic side effects of this drug, especially when given in the long term, remain a drawback in this setting. These side effects include hypersensitivity to the drug, sore throat, fever, joint pain and pancreatitis.30

It is generally accepted that operation is the definitive treatment for a gastrocolic fistula. Although a 2-stage operation was encouraged in the past, improvements in preoperative and postoperative care have allowed a 1-stage procedure to be performed safely in most cases. In the severely debilitated patient, a 2-stage procedure with a proximal diverting stoma has been advised, 18^,20^,31 but a preoperative course of intravenous hyperalimentation for the severely malnourished patient may obviate this.18

In terms of the type of operation, a variety of procedures have been recommended, depending on the extent of disease. Most authors advocate resection of the diseased colon and excision and primary repair of the fistulous opening. In some cases, because of the size of the fistula or significant involvement of the stomach, gastric wedge resection of the fistula or a partial gastrectomy may be required. In 2 instances, because of the presence of disease in the stomach, a sleeve resection of the stomach was used with resection of the fistula.26^, 27 In summary, operation is the mainstay of therapy for gastrocolic fistula in Crohn’s disease. Modern-day knowledge with appropriate nutritional support permits a 1-stage operative correction of this rare but debilitating condition.