eMedicine Specialties > Urology > Fistulas

Colovesical Fistula

Author: Joseph Basler, MD, PhD, Chief, Section of Urology, Audie Murphy Veterans Affairs Hospital; Associate Professor, Department of Surgery, Division of Urology, University of Texas Health Science Center, Bexar County Hospital
Coauthor(s): Angela Kamerer, MD, Attending Urologist, Gaston Urological Associates; Ann S Fenton, MD, MPH, Staff Physician, Department of Surgery, Division of Urology, Wilford Hall Air Force Medical Center
Contributor Information and Disclosures

Updated: Oct 8, 2007

Introduction

Normally, the urinary system is completely separated from the alimentary canal. Connections may result from (1) incomplete separation of the 2 systems during embryonic development (eg, failure of the urorectal septum to divide the common cloaca), (2) infection, (3) inflammatory conditions, (4) cancer, (5) injury, or (6) iatrogenic injury caused by surgical misadventures or postoperative complications. In the general practice of medicine, bowel disease that occurs adjacent to and erupts into the bladder is the most common cause of misconnection of the 2 systems. Fistulae from the bowel to the ureter and the renal pelvis are also possible but uncommon in the absence of trauma or surgical interventions. This article focuses on the more common causes, presentations, and treatments of enterovesical fistulae.

For excellent patient education resources, visit eMedicine's Cancer and Tumors Center and Kidneys and Urinary System Center. Also, see eMedicine's patient education articles Bladder Cancer and Bladder Control Problems.

History of the Procedure

As early as the second century AD, Rufus of Ephesus described fistulae between the bowel and the bladder. The common causes of acquired vesicoenteric fistulae have shifted from diseases of the past (eg, typhoid, amebiasis, syphilis, tuberculosis) to diverticulitis, malignancy, Crohn disease, and iatrogenic causes. Treatments have also evolved. In 1888, some suggested that colovesical fistulae "might be cured by a course of Bristol water and ass's milk."¹ Although more invasive, certainly less colorful, and possibly more palatable, a single-stage surgical approach is more commonly used today.

Problem

A fistula is an abnormal communication between 2 epithelialized surfaces. Vesicoenteric fistulae, also known as enterovesical or intestinovesical fistulae, occur between the bowel and the bladder. Vesicoenteric fistulae can be divided into 4 primary categories based on the bowel segment involved, as follows: (1) colovesical, (2) rectovesical (including recto-urethral), (3) ileovesical, and (4) appendicovesical fistulae. Colovesical fistula is the most common form of vesicointestinal fistula and is most commonly located between the sigmoid colon and the dome of the bladder. Rectourethral and rectovesical fistulae are observed in the postoperative setting, such as after prostatectomy, as a consequence of chronic infection or tissue destruction that accompanies massive decubiti, or in the setting of acute infections such as Fournier gangrene.

Frequency

Colovesical fistulae are the most common type of fistulous communication between the urinary bladder and the bowel. The relative frequency of colovesical fistulae is difficult to ascertain because multiple disease processes and surgical procedures could be complicated by such fistulae.

The incidence of fistulae in patients with diverticular disease, the most common cause of colovesical fistula, is generally accepted to be 2%, although referral centers have reported higher percentages. Only 0.6% of carcinomas of the colon lead to fistula formation.

Colovesical fistulae are more common in males, with a male-to-female ratio of 3:1. The lower incidence in females is thought to be due to interposition of the uterus and adnexa between the bladder and the colon. A 50% previous hysterectomy rate was found among women with colovesical fistulae. In women, other types of fistulae (typically iatrogenic, such as enterovaginal, ureterovaginal, and vesicovaginal) are more common than colovesical fistulae.

Etiology

Fistula formation is believed to evolve from a localized perforation that has an adherent adjacent viscus. The pathologic process is almost always intestinal. Pathologic processes characteristic of particular intestinal segments cause those segments to adhere to the bladder. Therefore, the location of the segment can suggest intestinal pathology.

Colovesical fistulae primarily result from diverticular disease. Ileovesical fistulae are most likely associated with Crohn disease. Rectovesical fistulae are more common in the setting of trauma or malignancy. Appendicovesical fistulae tend to be associated with a history of appendicitis.

Pathophysiology

Fistulae may be either congenital or acquired (eg, inflammatory, surgical, neoplastic). Congenital vesicoenteric fistulae are rare and are often associated with an imperforate anus.

Inflammatory pathophysiology

Diverticulitis accounts for approximately 50-70% of vesicoenteric fistulae. Diverticular fistulae are almost entirely colovesical. Diverticulitis complicated by a phlegmon or an abscess may adhere to the bladder and may eventually produce perforation into the bladder, causing a fistula. This complication occurs in 2-4% of cases of diverticulitis, although referral centers have reported a higher incidence.

Crohn disease accounts for approximately 10% of vesicoenteric fistulae and is the most common cause of an ileovesical fistula. Ileovesical fistulae develop in 10% of patients with regional ileitis. The transmural nature of the inflammation characteristic of Crohn colitis often results in adherence to other organs. Subsequent erosion into adjacent organs can then give rise to a fistula. The mean duration of Crohn disease at the time of first symptoms of fistula formation is 10 years, and the average patient age is 30 years.

Less-common inflammatory causes of colovesical fistulae include Meckel diverticulum, genitourinary coccidioidomycosis, and pelvic actinomycosis. Appendicovesical fistulae may complicate appendicitis. Enterovesical formation due to lymphadenopathy associated with Fabry disease has been reported.² Rarely, the bladder is the origin of the inflammatory process, as noted in a case report from Spain of bladder gangrene that caused a colovesical fistula in a patient with diabetes mellitus.³

Malignant pathophysiology

Malignancy accounts for approximately 20% of vesicoenteric fistulae. Colorectal cancer is the most common malignancy associated with vesicoenteric fistula. Malignancy is the second most common cause of colovesical fistulae.

Transmural carcinomas of the colon and rectum may adhere to adjacent organs and may eventually invade directly, causing development of a fistula. Such an event is uncommon today because most carcinomas are diagnosed and treated prior to this advanced stage.

Occasionally, carcinomas of the bladder, cervix, prostate, and ovary are implicated, and incidents involving small-bowel lymphoma have been reported.⁴ Rectovesical fistulae are frequently associated with malignancy. Interestingly, bladder carcinoma rarely, if ever, is associated with fistula formation. The reason for this may be earlier detection of bladder cancer.

Iatrogenic or traumatic pathophysiology

Iatrogenic fistulae are usually induced by surgical procedures, possibly tissue radiation, cancer, and/or infection. Surgical procedures, including prostatectomies, resections of benign or malignant rectal lesions, and laparoscopic inguinal hernia repair, are well-documented causes of rectovesical and rectourethral fistulae. Unrecognized rectal injury at the time of radical prostatectomy is an uncommon but well-documented etiology of rectourethral fistula.

External beam radiation or brachytherapy may cause bowel injury. Radiation-associated fistulae usually develop years after radiation therapy for a gynecologic or urologic malignancy. Fistulae develop spontaneously after perforation of the irradiated intestine, with the development of an abscess in the pelvis that subsequently drains into the adjacent bladder. Radiation-associated fistulae are usually complex and often involve more than one organ (eg, colon to bladder). Fistulae due to cytotoxic therapy have been reported in a patient undergoing a CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) regimen for non-Hodgkin lymphoma.⁵

Urethral disruption caused by blunt abdominal trauma or a penetrating injury can result in fistulae, but these fistulae are typically urethrorectal in nature. Foreign bodies in the bowel (eg, swallowed chicken bones or toothpicks) and peritoneum (eg, lost gallstone during laparoscopic cholecystectomy) have been reported to cause colovesical fistulae.^6,7

Presentation

The presenting symptoms and signs of enterovesical fistulae occur primarily in the urinary tract. Symptoms include suprapubic pain, irritative voiding symptoms, and symptoms associated with chronic urinary tract infection (UTI). Signs include abnormal urinalysis findings, malodorous urine, debris in the urine, hematuria, and UTIs.

The hallmark of enterovesicular fistulae may be described as Gouverneur syndrome, namely, suprapubic pain, frequency, dysuria, and tenesmus. Chills and fever are less common, and a colovesical fistula manifesting as sepsis is uncommon. Sepsis has been reported in 70% of patients with urinary outlet obstruction. The fistula may be asymptomatic and is seldom accompanied by dramatic or sudden abdominal symptoms or diarrhea. In most series, patients have been treated for recurrent UTI for 4-12 months before a fistula is diagnosed.

Pneumaturia and fecaluria may be intermittent and must be carefully sought in the history. Pneumaturia occurs in approximately 60% of patients but is nonspecific because it can be caused by gas-producing organisms (eg, Clostridium, yeast) in the bladder, particularly in patients with diabetes mellitus (ie, fermentation of diabetic urine) or in those undergoing urinary tract instrumentation. Pneumaturia is more likely to occur in patients with diverticulitis or Crohn disease than in those with cancer. Fecaluria is pathognomonic of a fistula and occurs in approximately 40% of cases. Patients may describe passing vegetable matter in the urine. The flow through the fistula predominantly occurs from the bowel to the bladder. Patients very rarely pass urine from the rectum.

Indications

The documented presence of a fistula that is causing symptoms or adversely affecting quality of life is an indication for surgical intervention in patients with enterovesical fistulae. Fistulae should be repaired in patients with abdominal pain, dysuria, malodorous urine, incontinence, urinary outlet obstruction, recurrent UTIs, bouts of sepsis, and pyelonephritis. Patients at high surgical risk may be treated with medical therapy and catheter drainage but may ultimately require at least diverting surgery if symptoms persist. Patients with terminal cancer are often better treated conservatively or with simple diversions.

Relevant Anatomy

Fistula formation is believed to evolve from a localized perforation to which an adjacent viscus adheres. The pathologic process is almost always intestinal and characteristic to particular intestinal segments that adhere to the bladder. The segments most commonly in proximity to the bladder include the rectum, sigmoid colon, ileum, jejunum, and appendix. Furthermore, the segment of bowel that is involved can suggest the intestinal pathology.

Colovesical fistulae primarily result from sigmoid diverticular disease. Ileovesical fistulae are most likely associated with Crohn disease. Rectovesical fistulae are more commonly due to trauma, surgery, or malignancy. Appendicovesical fistulae tend to be associated with a history of appendicitis.

Contraindications

Poor overall general health, inability to tolerate general or regional anesthesia, and terminal cancer are contraindications for aggressive management to cure a fistula. Patients with these contraindications may be served better with medical therapy or less invasive diversions (eg, colostomy, ureterostomy, percutaneous drainage).

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