Small Intestinal Fistula

Small Intestinal Fistula

http://www.bhj.org.in/journal/2001_4304_oct/case_590.htm

SMALL INTESTINAL FISTULA KETAN R VAGHOLKAR Associate Professor, Department of Surgery, Dr. DY Patil Medical College and Rajawadi Municipal General Hospital, Ghatkopar, Mumbai 77. India. Background : Groin swelling constitute one of the common problems encountered in surgical practice. If misdiagnosed and as a result mistreated the outcome could be disastrous. A misdiagnosed and mistreated groin swelling leading to a small intestinal fistula is presented. Methods : A 54 year old man was referred to hospital for a peculiar type of a small intestinal enterocutaneous fistula following a surgical procedure for a groin swelling, performed 9 months earlier. After having established the diagnosis of a fistulous communication by means of a fistulogram and in view of the chronicity of the disease, the patient was subjected to exploratory laparotomy. Result : Exploratory laparotomy revealed a fistulous communication between a segment of the small bowel and the external opening in the groin. Resection anastomosis of the affected segment of the small bowel along with excision of the fistulous tract was done. Conclusion : It is therefore concluded that the diagnosis and treatment of groin swellings should be done cautiously. A small intestinal fistula once formed is a great therapeutic challenge. Aggressive conservative methods followed by surgical intervention in the event of failure of response to conservative methods remains the mainstay of treatment. INTRODUCTION Small intestinal fistula is abnormal communication connecting the lumen of two segments of the small intestine, lumen of the small intestine with any other hollow viscus or between the small intestine and the skin of the abdominal wall. Despite refinements in the field of gastrointestinal surgery, the management of small intestinal fistula still remains a major clinical problem associated with high morbidity and mortality. CASE REPORT A 54 year old man was referred to the hospital with a discharging wound situated over the medial aspect of the left groin (Fig. 1). The patient had undergone surgical treatment for a groin swelling on the same side and site 9 months ago. No specific clinical or surgical details were available. The wound arising from the operation did not heal and formed a discharging fistulous opening at the site of operation. The output of the fistula was 50-100 ml per day. A fistulogram was done to delineate the anatomy of the fistulous tract. The fistulogram revealed a communication with a loop of the small intestine (Fig. 2 and 3). In view of the chronicity of the fistula and failure of response to conservative management a decision to surgically explore the abdomen was taken. The patient underwent exploratory laparotomy with resection anastomosis of the affected segment of the small intestine along with excision of the fistulous tract (Fig. 4).

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Fig 1 : Discharging wound over the medial aspect of the left groin

Fig 2 : Fistulogram (A-P View) reveals communication with a loop of the small intestine

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Fig 3 : Fistulogram (Lateral -view) reveals communication with a loop of the small intestine

Fig 4 : Gross findings : Resected specimen of the small intestine along with the fistulous tract

Histopathological examination of resected specimen did not reveal any specific features except for chronic inflammatory changes in the fistulous tract. Postoperative recovery of the patient was uneventful and the patient was discharged on the 12th Postoperative day. DISCUSSION The case report presented highlights the need for an accurate diagnosis of groin swellings prior to surgical intervention. The initial groin swelling was perhaps an inguinal hernia which was either misdiagnosed or mistreated. As a consequence of injury to the contents of the hernial swelling an enterocutaneous fistula resulted. Hence accurate preoperative diagnosis is pivotal in management of groin swellings. Irrespective of the aetiology of a small intestinal fistula, a fistula once formed poses a challenge to the surgeon despite great advances in the field of gastrointestinal surgery.

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Small intestinal fistula can be classified as internal, external or mixed. Internal fistulas wherein a communication exists between various segments of the small intestine or with any other hollow viscus but not with the skin of the abdominal wall are relatively infrequent. External fistulas are those in which the small intestine communicates with the skin of the abdominal wall. These are frequently encountered. The mixed variety is more complex and involves both internal and external communication, often through an abscess cavity. External fistulas are further classified on the basis of their output. Low output : Daily output not exceeding 200 ml. Moderate output : Daily output ranges from 200 to 500 ml. High output : Daily output exceeds 500 ml. Most small intestinal fistulas (75-80%) occur as a complication following surgery for abdominal malignancy, inflammatory bowel disease, tuberculosis or adhesiolysis. The most common surgical causes of fistula formation include anastomotic dehiscence after bowel resection and injury to the bowel. [1] The rest of the small intestinal fistulas (20-25%) include the spontaneous type seen in inflammatory bowel disease, radiation, diverticular disease, ischaemia and malignancy. Internal fistulas are difficult to diagnose. These are usually associated with inflammatory bowel disease or Crohn’s disease. [2] Enteroenteric or enterocolic fistulas may remain unrecognized if a small length of bowel is bypassed. However if longer lengths of bowel are bypassed there will be significant metabolic and nutritional disturbances. Enterovesical fistulas may present as recurrent UTI, with pneumaturia or faecaluria. External fistulas are usually picked up early in the clinical course. Disruption of the integrity of the small bowel results in local infection, with subsequent formation of an abscess. The typical clinical presentation includes a febrile postoperative course with an erythematous wound, that begins to leak purulent material and finally enteric contents. The seriousness of an external fistula depends on two crucial factors viz. its anatomic location and upon the volume of output it produces. Generally the more proximal a small bowel fistula, the larger the amount of output and subsequently the more severe the electrolyte disturbance and malabsorption produced. [1 ,3 ,4] Ileal fistulas are usually associated with low rates of spontaneous closure.[1] This may be related to the underlying disease process namely inflammatory bowel disease which is the frequent cause of ileal fistula. Other factors which prevent spontaneous closure of small bowel fistula are sepsis, malnutrition, epithelization etc. (Table 1). TABLE 1 Factors preventing spontaneous closure of small intestine fistulas Sepsis

Malignancy

Malnutrition

Irradiated Bowel

Foreign Body

Inflammatory Bowel disease

Abscess cavity linked to the fistulous tract

Complete disruption of the bowel ends.

Obstruction distal to the fistula

Epithelization of the fistulous tract

External fistulas are more prone to develop serious and lethal complications. Fluid and electrolyte abnormalities are commonly associated with external fistulas. [2 , 6] Sodium, potassium, magnesium, phosphate and zinc are most commonly affected. The development of malnutrition depends on the fistula output and is more likely in high risk fistulas. The loss of protein rich secretions from the fistula, alongwith the lack of adequate nutritional intake that may be seen in these patients contributes to malnutrition. Sepsis however is still a major complication in 25% to 75% of patients with external fistulas. [1, 5, 6, 12] Sepsis is the most common cause of death cited in various series making it mandatory that recognition and appropriate treatment occur at an early stage. [5,6] The most common method of diagnosing small bowel fistulas is a fistulogram for external fistulas, upper and lower GI series (for internal fistulas) and endoscopy for special cases (enterovesical fistulas). If an abscess cavity is suspected, localization of the abscess cavity is essential and can be done by USG or CT scanning. Scintigraphy (Indium 111-WBC Scintigraphy) is especially advantageous in the diagnosis of chronic disease such as Crohn’s disease where in it can accurately distinguish between fibrosis or scarring and active disease. [8] Fistulogram however remains the most important investigation for external fistulas. It has the ability to detect the exact anatomical course of the fistula which in turn may indicate the chance of spontaneous closure. If obstruction, active disease, or interruption of the bowel continuity exists, spontaneous closure is unlikely . If an abscess is associated with the fistula, the fistula continues to drain into the cavity until the abscess is drained. Various prognostic nutritional indicators have been suggested to identify the group of patients in whom spontaneous closure of the fistula is possible. [5] These are serum transferin, retinol binding protein and thyroxin binding prealbumin. However more trials are required to establish their prognostic efficacy. The treatment of small bowel fistulas depends on several factors, including the fistula location, cause of the fistula, fistula output, nutritional status, and the presence or absence of sepsis. The overall

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treatment goals in fistula management remain uniform (Table 2). The key components of nonoperative management of external fistulas in TPN, somatostatin, fluid replacement and aggressive prevention or treatment of sepsis. The use of TPN in patients with small bowel fistulas serves three roles, fluid replacement, electrolyte replacement and alleviation of catabolic state. [5, 7] Reduction of fistula output by the use of somatostatin may be especially important in treating high output fistulas. [9,10] Aggressive antibiotic therapy and care of the skin are the other important aspects which have to be taken care of. The chances of spontaneous closure are obviated if the fistula fails to close after 4-6 weeks of aggressive conservative methods. Surgical intervention is therefore warranted in external fistulas as well as in internal and mixed variety of fistulas. [11,12] Exteriorization of the affected bowel ends followed by definitive surgery after 12 weeks i.e. after the intra abdominal septic process has been treated remains the mainstay of surgical treatment. TABLE 2 Treatment goals in small bowel fistulas Prevent or treat fluid and electrolyte depletion. Control Drainage Control Sepsis Minimize the development of a catabolic state (TPN) Prevent skin excoriation

CONCLUSION In conclusion an accurate preoperative diagnosis has to be made of any parietal wall swelling in order to avoid damage to the bowel and thereafter a fistula. Aggressive TPN, somatostatin therapy, antibiotic therapy and meticulous care of the skin followed by surgical intervention in the event of failure of response to conservative therapy after a period of 4-6 weeks should be the approach to a small intestinal fistula. Despite aggressive modalities of treatment yet the rate of spontaneous closure is 40% to 50%, whereas 35-40% of patients do require active surgical intervention. [5 ,7 ,12] The overall mortality of small intestinal fistula is 15-25%. [1 ,5 ,11] ACKNOWLEDGEMENT I thank the Medical Superintendent of Rajawadi Municipal General Hospital, Ghatkopar, Mumbai - 77, India for allowing me to publish this Case Report. REFERENCES 1.Berry SM, Fischer JE. Enterocutaneous Fistulas. Curr Probl Surg 1994; 31 : 471-566. 2.Hill GL, Bourchier RG, Witney GB. Surgical and Metabolic Management of patients with external fistulas at the small bowel associated with Crohn’s disease. World J Surg 1998; 12 : 191-97. 3.Fischer JE. Ileal fistula, in Fischer JE (ed) : Common problems in Gastrointestinal Surgery. Chicago, Year Book Publishers. 1988; 289-97. 4.Mac Fadyen VB Jr, Dudrick SJ, Rubery RL. Management of Gastrointestinal fistulas with parenteral hyperalimentation. Surgery 1973; 74 : 100-5. 5.Kuvshinoff BW, Brodish RJ, Mc Fadden DW. Serum transferin as a prognostic factor of spontaneous closure and mortality in gastrointestinal - cutaneous fistulas. Ann Surg 1993; 217 : 615-23. 6.Soeters PB, Ebeid AM, Fischer JE. Review of 404 patients with gastrointestinal fistulas : Impact of parenteral nutrition. Ann Surg 1979; 190 : 189-202. 7.Rose D, Yarborough MF, Canizaro PD. One hundred and fourteen fistulas of the gastrointestinal tract treated with total parenteral nutrition. Surg Gynecol Obstet 1986; 163 : 1345-350. 8.Even - Sapir E. Indium 111 - White blood cell scintigraphy in Crohn’s patients with fistula and sinus tracts. J Nucl Med 1994; 35 : 245-50. 9.Nubiola P. Treatment of 27 post operative enterocutaneous fistulas with the long half life somatostatin analogue SMS 201-995. Ann Surg 1989; 210 : 56-58. 10.Buchler M, Friess H, Klempa I, et al. The role of somatostatin analogue octreotide in the prevention of postoperative complications following pancreatic resection. The results of a multicenter controlled trial. Am J Surg 1992; 163 : 125-30.

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11.Nassos TP, Braasch JW. External small bowel fistulas : Current treatment and results. Surg Clin North Am 1971; 51 : 687-92. 12.Edmunds LH, Williams GH, Welch CE. External fistulas arising from the gastrointestinal tract. Ann Surg 1960; 152 : 445-71.

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