Enterovesical Fistula - Types, Causes, Diagnosis and Treatment

Introduction:

Normally, the digestive tract and the organs present in it are completely separated from the urinary system. The digestive system comprises organs that work to digest food, whereas the urinary system works to eliminate waste products from the body. Therefore it can be concluded that the digestive system and the urinary system are different from each other. However, the problem arises due to communication between the two systems resulting in the enterovesical fistula. It has been named enterovesical because the communication starts from the intestine and ends at the urinary bladder.

What Are the Causes of Enterovesical Fistula?

Enterovesical fistula is more common in men compared to women. It is because the uterus is present between the bowel and the urinary bladder in women, so there is less chance of direct communication. The fistula can be present by birth or occur during the lifetime of an individual. The fistula is usually a result of a defect in the bladder and the intestinal wall. The causes of enterovesical fistula have been described below:

1. Diverticulosis - It is a condition in which pouches or sacs form in the walls of the intestines. When the pouches formed are more in number, they are known as diverticula. The inflammation of these pouches or diverticula is known as diverticulosis. Fistula is a major complication of diverticulitis. It is because diverticulitis can form a pus-filled area known as an abscess that can cause a hole in the intestine. As a result, the communication between the bladder and the bowel develops, known as an enterovesical fistula.

2. Crohn's Disease - In this condition, the patient experiences abdominal pain, vomiting, diarrhea, and loss of weight due to the inflammation of the digestive tract. If the condition becomes severe, an ulcer forms in the intestine and the infection spreads to the nearby organs like the anus, rectum, and urinary bladder. So, one of the causes of the enterovesical fistula is Crohn's disease.

3. Malignancy - Malignancy or cancer of a particular organ occurs when the cells divide rapidly. These cells cluster up and form a mass known as a tumor. The cells of the intestine also show uncontrolled growth in malignancy. As a result, cancer spreads from the intestine to the nearby organs and increases the risk of communication or fistula. Bladder cancer also spreads rapidly to nearby organs and increases the risk of enterovesical fistula.

4. Iatrogenic - Iatrogenic means the fistula can develop during a medical examination or treatments like radiotherapy and chemotherapy. The rectum (the organ that holds the stools) might get injured during prostate gland surgery, increasing the risk of a fistula. The patients receiving radiation therapy are at a higher risk of developing a fistula because the radiation can cause perforation in the intestine and other organs.

5. Trauma - Injuries to the pelvis during surgery and accidents are some of the causes of fistula. The pelvis supports the organs of the abdomen and the urinary system. In the case of pelvic injury, the risk of communication between the intestine, bladder, rectum, and other organs increases. Not only pelvic injuries but also foreign bodies present in the intestine can be a reason for communication or fistula.

What Are the Different Types of Enterovesical Fistulae?

The enterovesical fistula has been classified based on the parts of the bowel involved. It is important to know the parts of the bowel to understand the different types of fistulae. The bowel or the large intestine consists of the following parts:

• Cecum - It is the part of the large intestine that receives food from the small intestine and delivers it to the colon.

• Colon - The colon works to reabsorb water and electrolytes from food so that it reaches the rectum as solid waste and not liquid.

• Rectum - It holds the food waste received from the colon until it is defecated.

• Anus - It is a canal that allows solid food waste (stools) to pass through the body.

The different types of enterovesical fistula have been described in the table below:

What Are Some of the Signs and Symptoms of Enterovesical Fistula?

The symptoms of enterovesical fistula include the following:

1. Fecaluria - The presence of solid waste matter (fecal matter) in the urine is known as fecaluria. As a result, the urine appears cloudy and smells bad.

2. Dysuria - A burning sensation while passing urine is also known as dysuria. Urinary tract infection is the most common cause of pain and burning sensation while passing urine. It is a term used to describe the infection that can occur in any organ of the urinary system.

3. Gouverneur Syndrome - It is considered to be the hallmark of enterovesical fistula. The symptoms include pain in the lower abdomen, a burning sensation while passing urine, and the need to pass urine frequently.

What Methods Are Used to Diagnose Enterovesical Fistula?

The diagnosis of the enterovesical fistula is based on medical history and certain tests. The diagnostic methods are described below:

• Medical History - The medical history gives an idea about the symptoms of the condition, the time of their onset, other conditions the patient is suffering from, and the medications being taken.

• Computed Tomography (CT) Scans - CT scan is the most commonly opted diagnostic procedure because it provides the doctor with three-dimensional (3D) images of the body's internal organs. These images give an idea about the degree to which the colon is attached to the bladder, inflammation of the intestines at the site of communication, and the presence of air in the urinary bladder.

• Bourne Test - In this test, barium is injected into the body through the rectum. X-rays are taken as the colon gets filled with barium. The images obtained help to detect the abnormalities present in the intestinal wall. The patient might be asked to urinate, and the presence of barium in the urine confirms an enterovesical fistula.

• Cystography - In this procedure, a tube known as a catheter is used to fill the bladder with a special type of material, and X-rays are taken. This test is done to see if the fistula is due to a defect in the urinary bladder.

• Cystoscopy - It is a procedure in which the surgeon mainly inserts a small instrument known as the cystoscope into the urinary tract through the urethra to check the exact site of the fistula.

• Colonoscopy - A colonoscope is inserted through the rectum to view the intestine. It does not give any idea about the fistula, but the condition affecting the intestine that caused the fistula can definitely be detected.

• Poppy Seed Test - The poppy seeds are mixed in water or curd and fed to the patient. The patient is asked to collect urine for two days. If the urine shows the presence of poppy seeds, enterovesical or colovesical fistulae can be suspected.

What Are the Treatment Options for Enterovesical Fistula?

The following treatment options are recommended to treat enterovesical fistula:

1. Medications or Non-surgical Treatment - If the enterovesical fistula has developed due to Crohn's disease, the drugs like Azathioprine, Prednisolone (steroids), and Infliximab are usually recommended. These drugs also help to shrink the fistula to some extent.

2. Surgical Treatment - The surgery aims to remove the affected portion of the bowel and the fistula. The surgery is done in the following way:

   • The patient is administered Polyethylene glycol (PEG) and electrolytes to facilitate bowel movement before the surgery.

   • Cefuroxime is injected into the body through the veins for antimicrobial coverage.

   • The patient is made to fall asleep by injecting general anesthesia.

   • The portion of the bowel that communicates with the bladder is removed.

   • The removed portion is then sent to the laboratory to check if the communication is cancerous or non-cancerous.

   • The doctor inserts a nasogastric tube that allows the patient to feed because he does not eat anything until the bowel movements become normal.

   • A catheter is left in place for five to six days to allow the urine to pass normally.

   • After the healing is complete, the patient is asked to undergo a urine test to check if the communication between the bladder and the bowel has closed or not.

What Are the Complications of Enterovesical Fistula?

If the enterovesical fistula is left untreated for a long time, the risk of urinary tract infections will increase. It is because the bacteria can easily enter the urinary system through the catheter and cause infection. The contents of the bowel leak into the bladder and pass through the urine. The patient is unable to pass stool because of intestinal obstruction. Also, it takes time for the intestines to return to their normal activities after the surgery.

Conclusion:

Enterovesical fistula, or the communication between the bowel and bladder, is a major complication of the inflammatory disease of the intestine. The patient suffering from inflammatory diseases of the intestine needs to undergo treatment at the right time. It is not necessary that all cases require surgical intervention. There are medications available to reduce the inflammation and the size of the fistula. The patient must consult the doctor as soon as the symptoms are noted to live a healthy life ahead.