Introduction

A fistula is defined as an abnormal communication between two surfaces. An enteric fistula is an abnormal communication between the gastrointestinal tract. Abnormal connections may take the form of GI tract to skin, GI tract to other abdominal organs, or GI tract to chest. There are a number of symptoms that are related to an enteric fistula. That being said, there are operative and non-operative methods of managing an enteric fistula. Evaluation of the etiology of the fistula is important due to an up to 25% mortality due to sepsis and other complications related to the fistula.

 

Classification

It is important to classify the origin of the fistula. There are four main classifications with regards to the etilogy:

 

• Gastric
• Biliary
• Upper Intestinal
• Colonic

 

Another important classification is related to the output of the fistula. Though this is mostly related to enterocutaneous fistulas, this can relatively be applied to various enteric fistulas.

 

• Low-output (<200mL/day)
• Moderate-output (200mL-500mL/day)
• High-output (>500mL/day)

 

Fistulas are also related to certain diseases of the GI tract like Crohn’s disease:

 

Type 1: No Evidence of Active Disease

Type 2: Related with Intraabdominal abscess

 

Etiology

There are a number of etiologies of fistulas but the two leading causes are post-operative in origin, and Crohn’s disease. The following diagram outlines the etiology of fistulas and their frequency.

 

Signs and Symptoms

The most common presentation of an enteric fistula is abdominal drainage. More often than not, patients have a history of an abdominal surgery, or abdominal abscess. The typical course of a fistula is about 7-10 days after an operation. Other common signs and symptoms include abdominal discomfort, abdominal distension, tenderness, low-grade fever, signs of abdominal sepsis. Other more serious signs and symptoms include diarrhea, passage of air in urine, small bowel obstruction, gastrointestinal bleeding.

Diagnosis

Diagnosing an enteric fistula requires the identification of the fistula exit site. This may be difficult in enteric fistulas unless the abdomen is open. Imaging takes the form of a CT with and without contrast of the abdomen. But, CT is not enough to make the diagnosis. Anything suspicious in the CT should be followed up with a gastrointestinal contrast study. Fistulograms- done by injecting contrast to the opening of the tract- may demonstrate a fistula. However, this is not useful in identifying the origin of the tract. Lastly, a guidewire tracked using fluoroscopic guidance may be used.

 

https://www.youtube.com/watch?v=7ib4HebNnqs

 

Management

Initial management takes the form of correcting fluid and electrolyte imbalance, treatment of infection, abscess drainage, and skin care. Early identification and treatment of infection is important because of a number of complications such as sepsis, and peritonitis may occur. It is important to put patients on NPO until the source of the fistula is discovered. Basides supportive treatment, there are a number of medical and surgical options.

 

Medical Options

Medical options include anticathartics and somatostasin analogues. Anticathartics take the form of loperamide and diphenoxylate-atropine. This will help managing diarrhea with high-output fistulas. Somatostasin analogues such as octreotide will help with internal fistula output due to a decrease in gastric secretions.

 

Surgical Options

Fistula resection involves first identifying the segment of the bowel with the fistula. Once this is done, this part is removed surgically. Though typically only the offending portion is removed, patients with Crohn’s disease may require more extensive resections.

 

https://www.youtube.com/watch?v=GwB_bgUXqmM

 

Source:

https://www.uptodate.com/contents/overview-of-enteric-fistulas?source=history_widget#H21348536